MAC TOOLS EM721 Operation & User’s Manual

To reduce the risk of injury, read and understand these safety warnings and instructions before using the tool. Keep these instructions with the tool for future reference. If you have any questions, contact your MAC TOOLS representative or distributor. WARNING Automotive Multimeter User Manual EM721

year. Our obligation to the original purchaser shall be limited to repairing or replacing, at our expense (not including shipping charges) a defective tool if returned by the original purchaser within one year from the date of purchase, all incoming shipping charges prepaid. THIS WARRANTY DOES NOT COVER DEFECTS OR DAMAGES TO THE TOOL (i) after the warranty period expires; (ii) resulting from misuse or abnormal operation; (iii) resulting from a failure to properly maintain or operate the tool; or (iv) resulting from any repair or maintenance services performed by any party other than Mac Tools. This warranty does not cover expandable items such as batteries and/or fuses. LIMITATION OF LIABILITY This manual tells you how to use the meter to perform diagnostic tests and to find possible locations of automotive electronic problems. It does not tell you how to correct the problems. Once you have located a problem, consult your car’s service manual or other manuals to provide specific information needed for repair. All information, illustrations, and specifications contained in this manual are based on the latest information available at the time of publication. The right is reserved to make changes at any time without notice. TABLE OF CONTENTS 1. Safety Information .............................................................................. 4 2. Introduction ....................................................................................... 7 3. Front panel ........................................................................................ 8 4. Understanding the Display ................................................................ 14 5. Basic Electrical Tests and Measurements ........................................... 17 6. Basic Automotive Measurements ........................................................ 26 7. Basic Automotive Diagnostic Testing .................................................. 33 8. Basic Automotive Component Testing ................................................. 58 9. Summary of Automotive Electrical System Tests .................................. 67 10. Specifications .................................................................................. 70 11. General Specifications ..................................................................... 75 12. Maintenance .................................................................................... 76 13. Meter-PC Communication Software Instruction .................................... 77

AC Voltage 0.001V to 750V RPM IP 30 to 9000 RPM RPM IG 60 to 12000 RPM DC Current (Amperes) 0.1µA to 10A AC Current (Amperes) 0.1µA to 10A Resistance (Ohms) 0.1 to 40MΩ Frequency (Hertz) 0.5Hz to 200kHz % Duty Cycle 0 to 99.9% Dwell (Degrees) 0° to 356.4° Pulse Width (Milliseconds) 0.1ms to 1999.9ms Temperature (Fahrenheit/Celsius) - 40°F to +2498°F (- 40°C to +1370°C) Capacitance (Microfarads) 0.001µF to 999µF Continuity Check Beep at < about 40Ω in the 400Ω range

measurement category (CAT III 1000V) and Pollution Degree 2. WARNING TO AVOID POSSIBLE ELECTRIC SHOCK OR PERSONAL INJURY, FOLLOW THESE GUIDELINES: • Do not use the meter if it is damaged. Before you use the meter, inspect the case. Pay particular attention to the insulation surrounding the connectors. • Inspect the test leads for damaged insulation or exposed metal. Check the test leads for continuity. Replace damaged test leads before you use the meter. • Do not use the meter if it operates abnormally. Protection may be impaired. When in doubt, have the meter serviced. • Do not operate the meter where explosive (or flammable) gas, vapor, or dust is present. • Do not apply more than the rated voltage, as marked on the meter, between terminals or between any terminal and earth ground. • Before use, verify the meter’s operation by measuring a known voltage. • When servicing the meter, use only specified replacement parts. • Use caution when working with voltage above 30V ac rms, 42V peak, or 60V dc. • Such voltages pose a shock hazard. • When using the probes, keep your fingers behind the finger guards on the probes. • When making connections, connect the common test lead before you connect the • live test lead. When you disconnect test leads, disconnect the live test lead first. • Remove the test leads from the meter before you open the battery cover or the case. • Do not operate the meter with the battery cover or portions of the case removed or loosened. • To avoid false readings, which could lead to possible electric shock or personal injury, replace the battery as soon as the low battery indicator ( ) appears. • Do not use the meter in a manner not specified in this manual or the safety features provided by the meter may be impaired. • When measuring current using the test leads, turn off circuit power before connecting the meter in the circuit. Remember to place the meter in series with the circuit. • To avoid electric shock, do not touch any naked conductor with hand or skin; and do not ground yourself while using the meter. • Adhere to local and national safety codes. Individual protective equipment must be used to prevent shock and arc blast injury where hazardous live conductors are exposed. • Follow the relevant requirements and safety procedure specified in the users manual and service manual provided by the manufacturer of the vehicle under test. • Exhaust gas contains carbon monoxide which is odorless, causes slower reaction time, and can lead to serious injury. When testing vehicle with the engine running, testing should always be done in a well- ventilated area or vent exhaust gas outside the building. • Set the parking brake and block the wheels before testing or repairing the vehicle, unless instructed otherwise. It’s especially important to block the wheels on front-wheel drive vehicles: the parking brake doesn’t hold the drive wheels. The ignition or fuel system must always be disabled when performing starting system tests. • Always wear safety glasses when working near battery. • Do not smoke or allow open flames or sparks in the work area. Gasoline fumes and gases produced by battery are highly explosive. Keep cigarettes, sparks, and open flames away from batteries at all times. • To avoid personal injury, do not touch any moving or hot object. Keep body and clothing clear of moving or hot engine parts at all times.

well ventilated. Operate bilge blower for at least four minutes before starting engine or making test lead connections. • Always avoid working alone. • Do not use the meter if the meter or your hand is wet. • Remaining endangerment: When an input terminal is connected to dangerous live potential, it is to be noted that this potential can occur at all other terminals! • CAT III - Measurement Category III is for measurements performed in the building installation. Examples are measurements on distribution boards, circuit breakers, wiring, including cables, bus-bars, junction boxes, switches, socket-outlets in the fixed installation, and equipment for industrial use and some other equipment, for example, stationary motors with permanent connection to the fixed installation. Do not use the meter for measurements within Measurement Categories IV. CAUTION TO AVOID POSSIBLE DAMAGE TO THE METER OR TO THE EQUIPMENT BEING TESTED, FOLLOW THESE GUIDELINES: • Disconnect circuit power and discharge all capacitors thoroughly before testing resistance, diode, capacitor, temperature, and continuity. • Use the proper terminals, function, and range for your measurements. • Before measuring current, check the meter’s fuses and turn off power to the circuit before connecting the meter to the circuit. • Before turning the rotary switch to change functions, disconnect the test leads from the circuit being tested.

Caution, risk of danger, refer to the operating manual before use. Caution, risk of electric shock. Earth (ground) Terminal Fuse Conforms to European Union directives The equipment is protected throughout by double insulation or reinforced insulation.

This users manual tells you how to use the meter. You may also need a manual that provides technical information for the vehicle you plan to test. The most important information resources are the vehicle’s service repair manuals generally available for purchase through automotive dealers. They are also available through a number of publishers that specialize in providing technical information manuals to independent repair garages. This users manual servers as a guide to get you started with troubleshooting. You real learning can best be accomplished through experience. As you become more proficient in using this automotive multimeter for troubleshooting, you will quickly learn how certain electrical symptoms relate to various driveability problems. Meter Features • Accurate frequency and pulse measurements with 20,000 count on the high resolution 4000 count display. • High-speed 41-segment analog bargraph updates 20 times/sec - For nearly seamless real-time accuracy. • Accurate automotive electronics test and advanced measurements with DC/AC Volts, DC/AC Amps, Resistance, etc • Direct reading of dwell without using duty cycle-to-dwell conversion chart when testing electronic fuel injection, feedback carburetors, and ignition systems • RPM measurement for automotive engines with 1 to 12 cylinders using the test leads or the inductive pickup • mS-pulse width function to test on-time of fuel injectors of both PFI (Port Fuel Injector) and TBI (Throttle Body Injector) types • For accurate measurements of RPM, dwell, duty cycle, and mS-pulse width of injectors, the meter provides seven-step adjustable +/-triggers on 1 to 12 cylinders, either 2- or 4-cycle for outboards, motorcycles, and conventional engines • Temperature measurement up to 2,498°F (1,370°C) for catalytic converters, fan switch, etc. • Capacitance and non-automotive frequency measurement • Back-lighted display • USB communication

point placement. When this meter is turned on, all display segments and symbols appear briefly during a self test.

segment bargraph illuminates from left to right as the input increases. The bargraph is easier to read when the data causes the digital display to rapidly change. It is also useful for trend setting or directional data. The bargraph also indicates the trigger level. 3. “±TRIG “Button This “±TRIG” button can be used to toggle between negative (-) and positive (+) trigger slope and adjust trigger level. When the meter is in RPM, duty cycle, pulse width, frequency (automotive Hz) or dwell measurement function, hold down the “±TRIG” button for one second to toggle between negative (-) and positive (+) trigger slope. The slope is indicated by the + or - sign next to “TRIG” in the lower-left corner of the display. The meter defaults to negative (-) trigger slope. Once the trigger slope is selected, press the “±TRIG” button repeatedly to adjust trigger level if the meter reading is too high or unstable. The trigger level adjustment has seven steps. Press the “±TRIG” button to move one step at a time to select a suitable trigger level. TRIGGER STEP Voltage Level (RPM, Duty Cycle, mS, Hz (automotive), Dwell) Approximate Trigger Level as Indicated by Bargraph +4 +8.2V +3 +6.8V +2 +3.2V +1 +1.4V -1 -1.4V -2 -3.2V -3 -6.8V

Press this “REL” button to enter Relative mode. The meter stores the present reading as a reference for subsequent measurements. “ ” appears as a Relative mode indicator, and the display reads zero. In Relative mode, when you perform a new measurement, the display shows the difference between the reference and the new measurement. To exit the Relative mode, just press the “REL” button again. “ ” disappears. Note: • The meter enters manual range mode when you enter the Relative mode. • When you use Relative mode, the actual value of the object under test must not exceed the full- range reading of the selected range. Use a higher measurement range if necessary. • Relative mode is not available in diode and continuity test functions. Press and hold down this “REL” button for 1 second to turn on the USB communication function, “ ” will appear on the display as an indication. To turn off the USB communication function, press and hold down this “REL” button for 1 second again. “ ” disappears. 5. “DWL” Button This “DWL” button can be used to select dwell measurement function or switch between resistance and continuity test functions. When the meter is in RPM IG function, you can press this “DWL” button to select dwell measurement mode; “DWL°” will appear on the display as an indication. Dwell is the number of degrees of distributor rotation where the points remains closed. Dwell can be measured for 1 to 12 cylinders. The conversion between duty cycle and dwell can be obtained using the following formula: % Duty Cycle = Dwell (in degrees) × No. of Cylinders × 100% 360 degrees Dwell = 360 degrees × % Duty Cycle No. of Cylinders 100% When the meter is in the dwell function, you can press the “DWL” button again or the “% DUTY” button to return to the function the meter was in just before entering dwell function. When the rotary switch is in the “Ω ” position, you can press the “DWL” button to switch between resistance and continuity test functions. A continuity test can be used to verify that you have a closed circuit. The continuity function detects opens and shorts lasting as little as 100 milliseconds. In the 400Ω range, resistance of less than about 40Ω causes the built-in buzzer to sound. This can be a valuable troubleshooting aid when looking for intermittent faults associated with connections, cables, relays, switches, etc.

When the rotary switch is in “ “, “10 “, “m ” or “μ ” position, you can press this “DC/AC” button to switch between DC and AC function; when AC function is selected, “ ” will appear on the display as an indication; when DC function is selected, “ ” will appear on the display as an indication. You can press the “DC/AC” button to switch between °C and °F when the rotary switch is in “TEMP” position. When Celsius temperature measurement is selected, “°C” will appear on the display as an indication; and when Fahrenheit temperature measurement is selected,“°F” will appear on the display as an indication. 7. Rotary Switch Following functions are selected by setting the rotary switch: Switch Position Function Volts DC/AC m Millivolts DC only Ω Resistance/Continuity test (Ohms) Diode test Capacitance (Microfarads) TEMP Temperature (Fahrenheit and Celsius) Frequency (non-automotive frequency) measurement (Hertz) RPM measurement on 2- or 4-stroke engines using the Inductive Pickup on a spark plug wire. RPM measurement on 1 to 12 cylinder engines using the test leads in the primary side of the ignition coil and Duty Cycle, Pulse Width, Hz (automotive), and Dwell measurement. 10 Current (Amperes) DC/AC m Current (Milliamperes) DC/AC μ Current (Microamperes) DC/AC OFF Turns off the meter 8. “ ” Terminal Input terminal for voltage, resistance, continuity, RPM, diode, frequency, capacitance, temperature, duty cycle, pulse width and dwell measurements.

10. “mA μA” Terminal Input terminal for current measurements < 400mA. 11. “A” Terminal Input terminal for current measurements between 400mA and 10A. 12. “RANGE” Button This “RANGE” button can be used to: • Toggle between autorange mode and manual range mode as well as to select desired manual range. • Select number of cylinders (1, 2, 3, 4, 5, 6, 8, 10, or 12) to match the engine when the meter is in RPM IG or dwell function. • Toggle between 2-Cycle engine (or distributorless ignition system 4-Cycle engine) and 4-Cycle engine when the meter is in RPM IP function. In a function which has both autorange mode and manual range mode, the meter defaults autorange mode and “ ” appears on the display as an indication. You can press the “RANGE” button to enter manual range mode, “ ” will disappear and the meter will stay in the present range. In manual range mode, you can press the “RANGE” button to select the next higher range. After the highest range, the meter wraps to the lowest range. To exit manual range mode and return to autorange mode, press and hold down the “RANGE” button for 1 second; “ ” will appear on the display as an indication. Always select a range higher than you expect the current or voltage to be. Then select a lower range if better accuracy is needed. If the range is too high, the readings are less accurate. If the range is too low, the meter shows “OFL” as an overload indication. When the meter is in the RPM IG or dwell function, press the “RANGE” button to toggle between 1, 2, 3, 4, 5, 6, 8, 10, 12 cylinder engines. The selected number of cylinders is indicated by the number preceding CYL on the display. When the meter is in the RPM IP function, press the “RANGE” button to toggle between 2-cycle engine (or distributorless ignition system 4-cycle engine) and 4-cycle engine; the selected number of cycles (or strokes) is indicated by the corresponding symbol (“ ” or “ ”). 13. “% DUTY” Button When the meter is in RPM IG function, press this “% DUTY” button to measure duty cycle (or duty factor) in percent; % readout is displayed. Duty cycle is the percentage of time a signal is above or below a trigger level during one cycle.

the length of time an actuator is energized. For example, fuel injectors are activated by an electronic pulse from the Engine Control Module. This pulse generates a magnetic field that pulls the injector nozzle valve open. The pulse ends and the injector nozzle is closed. This Open-to-Closed time is the pulse width and is measured in milliseconds (mS) To select the frequency function, press the “% DUTY” button once more; Hz readout is displayed. Frequency is the number of cycles a signal completes each second. You can step through RPM, duty cycle, pulse width, and frequency by pressing this “% DUTY” button. When the rotary switch is in the “RPM IG” position, you can press the “DWL” button to select dwell measurement function; “DWL°” will appear on the display as an indicatior for the dwell measurement function. When in dwell measurement function, you can press the “DWL” button again or the” % DUTY” button to go back to the previous function from which the meter entered the dwell measurement function. 14. “HOLD” Button Used to enter or exit Hold mode as well as to turn on or off the backlight. Press this “HOLD” button to enter the Hold mode. “ ” appears on the display as an indication and the meter holds the present reading on the display. In the Hold mode, whenever meter detects a new stable reading, the meter sounds a beep and displays the new stable reading. To exit the Hold mode, press the “HOLD” button again. “ ” disappears. Note: When the meter is in the Recording or Relative mode, the Hold function simply freezes the present reading and will not update the the display with new stable reading. To turn on or off the backlight, press and hold down this “HOLD” button for 1 second. 15. “REC” Button Press the “REC” button to enter the Recording mode, “ ” will appear on the display as an indication. (The meter will exit autorange mode automatically and stay in the present range when it enters Recording mode.) This function allows you to record maximum, minimum, and average values for a series of measurements in the same function and range. This meter beeps each time a new maximum or minimum value is recorded. Press the “REC” button to scroll through the stored maximum, minimum, and average values. When an overload is captured, a beeper tone is emitted and the meter displays “OFL” as an overload indication. The meter can only record for 24 hours in this mode. Note: In diode or continuity function, the Recording mode is not available. 16. USB Port

When the rotary switch is in the position, the meter will turn off automatically if you have not operated the meter for about 30 minutes (1 hour in the Recording mode) while the input voltage is less than 1V. When the rotary switch is in other position, the meter will turn off automatically if you have not operated the meter for about 30 minutes (1 hour in the Recording mode). About 30 seconds before the meter turns off automatically, the symbol “ ” will start flashing to remind you that the meter will turn off. To turn on the meter again, set the rotary switch to OFF position first and then set it to a desired position. To disable the automatic power-off feature, turn on the meter while holding down the “HOLD” button. Using Inductive Pickup The meter comes with an Inductive Pickup. The Inductive Pickup takes the magnetic field generated by the current in the spark plug wire and converts it to a pulse that triggers the meter’s RPM measurement. 4. UNDERSTANDING THE DISPLAY 2 1 5 6 9 8 7 13 12 11 10 14 15 16 17 18 19 20 22 23 24 25 26 3 4 21

12 cylinder engines can be measured using the test leads on the primary side of the ignition coil. 2. . Displayed when the RPM IP mode is selected. In this mode, revolutions per minute on 2- or 4-stroke engines can be measured using the Inductive Pickup on a spark plug wire. 3. . Displayed when dwell mode is selected. 4. . Displayed when duty cycle mode is selected. 5. 18 . Displayed when a certain number of cylinders is selected in the RPM IG or Dwell mode. Press the “RANGE” button to toggle between 1, 2, 3, 4, 5, 6, 8, 10, 12 cylinder engines. 6. . Displayed when 4 strokes are selected in the RPM IP mode. Press the “RANGE” button to toggle between 2-stroke and 4-stroke engines. 7. . Displayed when 2 strokes are selected in the RPM IP mode. Press the “RANGE” button to toggle between 2-stroke and 4-stroke engines. 8. . Indicates that the value being displayed is the average of all readings taken since the Recording mode was entered. 9. . Displayed when diode test is selected. 10. . Displayed when Relative mode is active. 11. . Displayed when Recording mode is active. 12. . Displayed when continuity test is selected. 13. . Displayed when the Hold mode is active. 14. . Displayed when the battery is low. WARNING TO AVOID FALSE READINGS, WHICH COULD LEAD TO POSSIBLE ELECTRIC SHOCK OR PERSONAL INJURY, REPLACE THE BATTERY AS SOON AS THIS LOW BATTERY INDICATOR APPEARS. 15. . Indicates that the value being displayed is the maximum reading taken since the Recording mode was entered. 16. . Displayed when autorange mode is active. 17. . Indicates that the value being displayed is the minimum reading taken since the Recording mode was entered. 18. . Displayed when DC measurement function is selected. 19. . Displayed when AC measurement function is selected. 20. . Indicates negative readings. In Relative mode, this sign indicates that the present input is less than the stored reference. 21. . Indicates that the automatic power-off feature has been enabled. 22. . Indicates that USB communication function has been turned on. 23. . Displayed when a – or + trigger slope is selected while the meter is in the RPM IP or RPM IG (Duty Cycle, Pulse Width, Hz or Dwell) mode. The meter defaults to a – (negative) trigger slope. Press the “± TRIG” button for 1 second to toggle between negative (-) and positive (+) trigger slope. Also displayed when the bargraph indicates trigger level.

Also indicates a – (negative) or + (positive) trigger slope when a trigger slope is selected. HIGH TIME LOW TIME 1 DUTY CYCLE Select a negative (-) trigger slope to measure low (-) time and a positive (+) trigger slope to measure high (+) time. For example, when measuring duty cycle of the Mixture Control Solenoid, the low (-) time is the On time in most cases. 25. ANALOG DISPLAY SCALE. Displayed with 41-position analog pointers. 26. The following symbols indicate the unit of the value displayed: DWL° The number of degrees of distributor rotation where the points remain closed, measured for 1 to 12 cylinders % Percent, used for duty cycle measurement °C/°F Centigrade or Fahrenheit temperature measurement Ω Ohms kΩ Hertz (1 cycle/sec) Kilohertz (1 × 10 cycles/sec) Volts Millivolts (1 × 10 Volts) Amperes (Amps) Milliamperes (1 × 10 Amps) Microamperes (1 × 10 Amps) Microfarads (1 × 10 Farads) Milliseconds (1 × 10 seconds) Megohm (1 × 10 Ohms) 6 3 -3 -3 -6 -6 -3 3 Kilohm (1 × 10 Ohms) MΩ Hz kHz V mV A mA µA µF mS

One of the most common electrical diagnostic tools is a digital multimeter (DMM). A DMM is simply an electronic yardstick for making electrical measurements. DMMs have many special functions and features, but the most common use is to measure voltage, current, and resistance. An automotive multimeter such as this automotive multimeter can also measure frequency, RPM, duty cycle, dwell, pulse width, temperature, capacitance, and even the condition of diodes. General Considerations for Making Measurements • Accuracy A measurement range determines the highest value the meter can measure. Most Meter functions have more than one range. When making a measurement, it is very important that you are in the right measurement range. Selection of a lower range moves the decimal point one place to the left and increases the accuracy of the readings. When the LCD shows OFL (overload), the range is too low; select the next higher range. • Analog Bargraph The bargraph is useful for trend setting or directional data. It is easiest to read when the data causes the digital display to change rapidly. • Safety Shutter When measuring voltage, be sure that the red test lead is connected to the “ ” input jack; if the red test lead is connected to the “A” or “mA μA” jack, you may be injured or the meter may be damaged. When measuring current, do not connect the red test lead to the “ ” input jack. The safety shutters of the meter are used to prevent inadvertent connection to wrong input terminal. Voltage Measurements Voltage measurements are dynamic tests that measure the voltage across a circuit or component with the power on. Voltage measurements are made with the test leads connected across the circuit element under test. WARNING TO AVOID ELECTRICAL SHOCK AND INSTRUMENT DAMAGE, INPUT VOLTAGE MUST NOT EXCEED 1000V DC OR 750V AC RMS. DO NOT ATTEMPT TO MEASURE ANY UNKNOWN VOLTAGE THAT MAY EXCEED 1000V DC OR 750V AC RMS. NOTE: When making voltage measurement, this meter must be connected in parallel with the circuit or circuit element under test.

• Set the rotary switch to the voltage ( or m ) setting. (The m setting is only for DC millivolt measurements.) • Press the “DC/AC” button to select AC or DC voltage measurement, the display will show the corresponding symbol. • Insert the black lead in the “COM” jack. • Insert the red lead in the “ ” jack. Connect: Back probe to the negative (-) circuit or to ground. Red probe to the circuit coming from the power source. Resistance Measurements Resistance is a static measurement which means that it must be measured with the power off. It is measured in Ohms (Ω) and the values can vary greatly from a few milliohms (mΩ) for contact resistance to billions of ohms for insulators. WARNING TURN OFF POWER AND DISCHARGE ALL CAPACITORS IN THE CIRCUIT TO BE TESTED BEFORE MAKING IN-CIRCUIT RESISTANCE MEASUREMENTS. ACCURATE MEASUREMENT IS NOT POSSIBLE IF EXTERNAL OR RESIDUAL VOLTAGE IS PRESENT. NOTE: The resistance in the test probes can affect accuracy in the 400 range. Short the probes together and press the “REL” button to subtract test lead resistance from the measurement.

• Set the rotary switch to the Ω setting. The meter defaults to resistance measurement function. • If a more accurate measurement is desired, select the proper resistance range by pressing the “RANGE” button. • Insert the black lead in the “COM” jack. • Insert the red lead in the “ ” jack. Connect: • Test probes across the resistor or circuit to be tested. Accuracy: Rapidly changing display readings (noise) can sometimes be eliminated if you change to a higher range. You can also smooth out noise somewhat by using the averaging (AVG) feature provided by the Recording function. Continuity Test A continuity test is a static test (circuit power off) that allows you to quickly and easily distinguish between an open and a closed circuit. When the meter detects a closed circuit or short, it beeps so you do not have to look at the meter during the test. This can be a valuable troubleshooting aid when determining good or blown fuses and fusible links, open or shorted conductors and wires, operations of switches, etc. It is also helpful for troubleshooting in out-of-the-way locations where it is difficult to watch the readout at all times. NOTE: Turn off power to the circuit to be tested. A beeper tone does not necessarily means zero resistance.

Meter setup to test circuit continuity: • Set the rotary switch to the Ω setting. • Press the “DWL” button until “ ” appears on the display. Now the meter is in continuity test function and the meter defaults to the 400Ω range. • Insert the black lead in the “COM” jack. • Insert the red lead in the “ ” jack. Connect: • Test probes across the circuit to be tested. If the circuit is closed (resistance < about 40Ω), the meter will beep. If the circuit is open (resistance > 150Ω), there is no beep. Red Black CLOSED CIRCUIT - BEEP SOUNDS

voltage is over a certain level, generally greater than 0.3V for a silicon diode. The meter has a static diode test mode to test diodes when the circuit power is off. Readings across a good diode will typically be greater than 0.3V in one direction, while indicating an open circuit in the other direction. NOTE: Turn off power to the circuit to be tested. Red Black Meter setup to test the diode: • Set the rotary switch to the setting. • Insert the black lead in the “COM” jack. • Insert the red lead in the “ ” jack. Connect: • Black test probe to the cathode of the diode. • Red test probe to the anode of the diode. If the diode is good, the reading should indicate 0.3V to 0.8V on the display. Reverse the probes. The display should show “OFL” if the diode is good. NOTE: A defective diode may read OFL (OverFLow) or have the same reading in both directions no matter how the test probes are connected.

the power on. Current measurements are made with the test leads connected in series with the circuit or component under test. CAUTION TO AVOID DAMAGE TO THE METER, CURRENT SOURCES HAVING OPEN CIRCUIT VOLTAGES GREATER THAN 1000V DC OR 750V AC MUST NOT BE MEASURED. NOTE: When making current measurements, the meter must be connected in series with the circuit (or circuit element) under test. To avoid damage to the meter or the equipment under test, never connect the test probes across a voltage source when the meter is in current measurement function. 12V Battery Red Black Meter setup to measure current: • Set the rotary switch to a current (10 ,m , or μ ) setting. • Press the “DC/AC” button to select AC or DC current measurement, the display will show the corresponding symbol. • Insert the black lead in the “COM” jack. • If the current to be measured is between 400mA and 10A, insert the red test lead in the “A” jack. If the current is less than 400mA, insert the red test lead in the “mA μA” jack instead. • Turn off power to the circuit to be tested. Then discharge all high-voltage capacitors. • Break the circuit path to be tested, creating a point where the test probes can be connected in series with the circuit.

Turn on power to the circuit, then read the display. For DC current measurements, the polarity of the red test lead connection will be indicated as well. Note: 1. If the red lead is connected to the “A” jack, the rotary switch must be set in the 10 position. If the red lead is connected to the “mA μA” jack, the rotary switch must be set in the m or μ position. 2. If the magnitude of the current to be measured is not known beforehand, select the highest range first and then reduce it range by range until satisfactory resolution is obtained. Temperature Measurements Temperature measurements can be made dynamically (power on) but care must be taken so the temperature probe does not come in contact with voltage levels that might damage the probe or the meter. CAUTION DO NOT ALLOW TEMPERATURE PROBES TO CONTACT ANY VOLTAGE THAT MAY EXCEED 30V AC, 42V PEAK OR 60V DC. KEEP THE METER AWAY FROM SOURCES OF VERY HIGH TEMPERATURES TO PREVENT DAMAGE. NOTE: To avoid possible damage to the meter or other equipment, remember that while the meter is rated for -40°C to 1370°C and -40°F to 2,498°F, the K Type Thermocouple provided with the meter is rated to 480°C. For temperatures out of that range, use a higher rated thermocouple. The K Type Thermocouple provided with the meter is a present. For accurate measurements, use a professional- grade thermocouple. K type thermocouple Object TEMP

• Set the rotary switch to TEMP setting. Note: The meter defaults to Celsius temperature measurement mode. You can press the “DC/AC” button to switch between Celsius and Fahrenheit temperature measurement if necessary. • Insert the plug of the K type thermocouple into the “COM” and “ ” jacks as shown, make sure that the polarity connections are correct. Connect: • Tip of the K type thermocouple to the area or surface to be measured. Read the reading on the display. Capacitance (CAP) Measurements Capacitance measurements check the condition of capacitors under static (power off) conditions in microfarads (µF). CAUTION TURN OFF POWER TO THE CIRCUIT TO BE TESTED. THOROUGHLY DISCHARGE THE CAPACITOR TO BE TESTED BY SHORTING THE CAPACITOR LEADS TOGETHER. USE THE DC VOLTAGE FUNCTION TO CONFIRM THAT THE CAPACITOR IS DISCHARGED. NOTE: In the 1µF range, readings may be unstable due to environmentally induced electrical noise and floating capacity of the test probes. Therefore, connect the capacitor directly to the input terminals. Black Red Parallel Connection

• Set the rotary switch to the Capacitance ( ) setting. • Insert the black lead in the “COM” jack. • Insert the red lead in the “ ” jack. Connect: • Test probes to the capacitor. When measuring polarized capacitors, connect the red probe to the anode of the capacitor and the black probe to the cathode of the capacitor. Wait until the reading is stable, then review the reading on the display. Hi-Sen Frequency (Hz) Measurements This meter has two frequency measurement modes: the High-Sen (high sensitivity – trigger level of about 250mV) mode for the general frequency counter mode and the Hz or RPM IG mode for automotive measurement. In the High-Sen Frequency counter mode, the meter autoranges to one of the four ranges: 200Hz, 2000Hz, 20kHz, and 200kHz. If the input signal is below the trigger level, frequency measurements will not be taken. If your readings are unstable, the input signal may be near the trigger level for that range. You can usually correct this by selecting a lower range using the “RANGE” button. If your readings seem to be a multiple of what you expect, your input signal may have distortion or ringing, which is common to signals from electronic motor controls. In this case, use the Hz or RPM IG mode to get the correct readings. Reference Voltage Side Signal Output Ground Black Red

• Set the rotary switch to the Hi-Sen Hz ( ) setting. • Insert the black lead in the “COM” jack. • Insert the red lead in the “ ” jack. Connect: • Black test probe to ground. • Red test probe to the signal output lead of the object to be tested. NOTE: The display will show 0.00Hz for frequencies below 0.5Hz. 6. BASIC AUTOMOTIVE MEASUREMENTS RPM Measurements Using the Inductive Pickup (RPM IP mode) RPM (revolutions per minute) can be measured in the RPM IP mode using the inductive pickup (standard accessory). Clamp the inductive pickup around any spark plug wire; the inductive pickup converts the magnetic field generated by the current flow in the spark plug wire into a pulse that triggers the meter’s RPM measurement. With the inductive pickup, you can make RPM measurements on any two- or four-stroke automotive engine with any number of cylinders without physically connecting to any test points or wires. WARNING THE IGNITION SYSTEM POSES A POTENTIAL SHOCK HAZARD. ENSURE THAT THE ENGINE IS OFF BEFORE CONNECTING OR REMOVING THE INDUCTIVE PICKUP.

• Set the rotary switch to RPM IP (RPM IP) setting. • Press the “RANGE” button to select either 2 or 4 stroke engine. • Insert the black plug of the inductive pickup into the “COM” jack and the red plug of the inductive pickup into the “ ” jack. Connect the inductive pickup to any spark plug wire and start the engine. If no reading is received, unhook the pickup, turn it over, and connect again. If the reading is too high or unstable, adjust trigger level. NOTE: Position the pickup away from the distributor and the exhaust manifold, but as close as possible to the spark plug. If no reading or an erratic reading is displayed, first reverse the inductive pickup; then move the pickup to another spark plug wire and test again. RPM Measurements Using Test Probes (RPM IG mode) RPM can be measured using the test probes connected to the primary side of a conventional distributor-type ignition coil. Before measuring RPM, you need to determine whether you are looking at a 2- or 4-stroke engine and how many cylinders are in the engine. When the RPM IG setting is first selected, the meter defaults to four strokes and four cylinders so that , , 4CYL, , and _ appear on the display. If you want to select a different number of cylinders, press the “RANGE” button repeatedly to cycle through the number of cylinders between 1 and 12 (excluding 7, 9 and 11). The number of strokes can not be changed in the RPM IG mode; you must temporarily switch to the RPM IP mode, then change strokes by pressing the “RANGE” button, and then return to the RPM IG mode.

BEFORE CONNECTING AND REMOVING THE TEST PROBES. Conventional Ignition Coil Spark Plug Black Red RPM IG Meter setup to measure RPM: • Set the rotary switch to the RPM IG (RPM IG) setting. • If “RPM IG” is not present on the display, press the “%DUTY” button until “RPM IG” appears on the display. • Press the “RANGE” button to select the number of cylinders. • Insert the black lead in the “COM” jack. • Insert the red lead in the “ ” jack. Connect: • Black test probe to a good ground near the coil. • Red test probe to the primary side of the ignition coil. Start the engine and note the reading on the display while moving the throttle. If the reading is too high or unstable, adjust the trigger level. NOTE: Refer to the car’s service manual for information on the number of strokes and cylinders for specific engines.

Duty cycle (or duty factor) is the percentage of time a signal is above or below a trigger level during one cycle. There are many signals on the vehicle where you may need to measure duty cycle. For example, signals from the mixture control solenoid of a feedback carburetor, signals from cam or crank sensors, and the control signals for fuel injectors. This example uses the meter to measure duty cycle on the mixture control solenoid signal of a feedback carburetor. Black Good ground Red Jumper leads from feedback solenoid RPM IG Meter setup to measure duty cycle: • Set the rotary switch to the RPM IG (RPM IG) setting. • Press the “%DUTY” button until “%” appears on the display. • Insert the black lead in the “COM” jack. • Insert the red lead in the “ ” jack. Connect: • Jumper wires between the feedback solenoid and the harness connector. • Black test probe to a good ground near the carburetor or the negative (-) vehicle battery post. • Red test probe to the solenoid control signal. Press and hold down the “±TRIG” button for 1 sec to toggle between negative (-) and positive (+) slope. Start the engine. A duty cycle of about 50% should be read. If reading is too high or unstable, adjust the trigger level by pressing the “±TRIG” button repeatedly. For most cars, the points of the solenoid are closed for a duty cycle between 50% and 70%.

NOTE: Refer to the car’s service manual to verify slope for each component. Pulse Width Measurements Pulse width is the length of time an actuator is energized. For example, fuel injectors are activated by an electronic pulse from the Engine Control Module (ECM). This pulse generates a magnetic field that pulls the injector nozzle valve open. The pulse ends and the injector nozzle closes. This Open-to-Close time is the pulse width and is measured in milliseconds (mS). Automotive applications for measuring pulse width include fuel, fuel mixture control solenoids and the idle air control motor. The following example shows how to measure pulse width on port fuel injectors. RPM IG Black Good ground Red Jumper leads from feedback solenoid Meter setup to measure pulse width: • Set the rotary switch to the RPM IG (RPM IG) setting. • Press the “%DUTY” button until “mS” appears on the display. • Press and hold down the “±TRIG” button for 1 sec until the negative (-) trigger slope is displayed. NOTE: The On time for most fuel injectors is displayed on the negative (-) slope. • Insert the black lead in the “COM” jack. • Insert the red lead in the “ ” jack.

• Black test probe to a good ground near the fuel injector or the negative (-) vehicle battery post. • Red test probe to the fuel injector solenoid driver input on the jumper cable. Start the engine. Pulse width is shown in milliseconds. If reading is too high (overrange) or unstable, adjust the trigger level by pressing the “±TRIG” button repeatedly. Frequency (Automotive Hz) Measurements Frequency is the number of cycles a signal completes each second. There are many sensors and signals on a vehicle that produce a frequency that can be measured. For example, wheel speed sensors, vehicle speed sensors, fuel injector control signals, cam and crank outputs, and engine reference signals. This example measures the frequency output of a digital mass air flow sensor (MAF). Output can vary from several hundred Hz to ten thousand Hz depending on the type of MAF sensor. NOTE: Although similar in appearance, MAF sensors made by different manufacturers function differently, have different frequency ranges and squarewaves, and are not interchangeable. Voltage level of squarewaves should be consistent. Frequency should change smoothly with engine load and speed. RPM IG Black Black lead to the MAF signal ground Red lead to the MAF signal output Jumper leads from MAF sensor Red Meter setup to measure frequency: • Set the rotary switch to the RPM IG (RPM IG) setting. • Press the “%DUTY” button until “Hz” appears on the display. • Insert the black lead in the “COM” jack. • Insert the red lead in the “ ” jack.

• Black test probe to the ground jumper wire. • Red test probe to the signal output jumper wire. Start the engine. Note the frequency shown on the meter display at idle. Advance the throttle and note the change in frequency. NOTE: Refer to the car’s service manual for correct frequency readings. If reading is unstable, adjust the trigger level by pressing the “±TRIG” button repeatedly. Dwell Measurements Dwell is the number of degrees of distributor rotation that the points remain closed. Dwell can be measured for 1, 2, 3, 4, 5, 6, 8, 10, or 12 cylinder engines using the meter. Before measuring dwell, you need to determine how many cylinders are in the engine. In the Dwell mode, the meter defaults to four cylinders and negative (-) slope, so , 4CYL, , and _ are displayed. If you want to select a different cylinder number, press the “RANGE” button repeatedly to select the correct number of cylinders. RPM IG Breaker Pointers/ Ignition Module Black Red Good Ground Meter setup to measure dwell: • Set the rotary switch to the RPM IG (RPM IG) setting. • Press the “DWL” button until “ ”, “4CYL”, “ ”, and “_” appears on the display. • Insert the black lead in the “COM” jack. • Insert the red lead in the “ ” jack.

• Red test probe to the wire that connects to the breaker points. Press the “RANGE” button repeatedly to select the required number of cylinders. Start the engine and observe the reading. If the reading is too high or unstable, adjust trigger level by pressing the “±TRIG” button repeatedly. 7. BASIC AUTOMOTIVE DIAGNOSTIC TESTING A systematic series of tests that check the vehicle electrical system should be performed before testing individual automotive components. The following basic tests check the primary areas responsible for the majority of the electrical problems found in an automobile. Perform these tests first, even if a fault or trouble code is set in the on-board computer. A basic ground problem in the electrical system can cause a component malfunction detected by the on-board. If the problem is caused by a poor ground, simply replacing a failed component will not provide a cure. Basic diagnostic testing should begin by checking the main source of power and the chassis ground circuit connections. Ground circuits are potentially the most troublesome areas of automotive electronics, yet they are least understood and hardest to diagnose. One of the most frustrating electrical problems you will encounter in an automobile is a high-resistance ground. This can create some very strange symptoms that seem to be unrelated to the cause. The symptoms can include problems with turn signals, lights that stay dim, the wrong lights turning on, transmission shifting problems, gauges that change when certain accessories are operated, or even lights that will not turn on at all. You can find a bad ground by checking the voltage drop between the component’s ground wire and a clean chassis ground or the negative vehicle battery terminal. An excessive voltage drop in a ground circuit affects the entire electrical circuit. That is why it is so important to make sure the basic circuits are in good shape before checking trouble codes in the on-board computer and individual components. BATTERY TESTS If you are having electrical problems, first test the battery. If the battery is low or discharged, it must be thoroughly recharged before tests can begin. A discharged battery may also indicate a problem in the charging circuit. Batteries are often blamed for “no- start” conditions when, in fact, the real problem exists in the charging system. After a charging system problem exists for some period of time, the battery becomes discharged and can not supply enough current for the starter to crank the engine. Many electrical problems are caused by current drains and shorts. Current drains that cause dead batteries are often referred to as shorts, even though they are not actually short circuits. Shorts that blow fuses can be found using the same troubleshooting techniques used to find current drains, even though the symptoms are different.

them before beginning tests. CAUTION THE IGNITION SWITCH MUST BE OFF TO PREVENT DAMAGE TO THE VEHICLE COMPUTER WHEN CONNECTING OR DISCONNECTING BATTERY CABLES. Battery Surface Discharge Test The test checks for a low current discharge across the battery case. Dirt, moisture, corrosion are typical causes of surface discharge. Clean the battery surface with a baking soda and water solution to prevent surface discharge. However, never let the solution get into the battery. Positive battery cable Negative battery cable Black Red 12V battery Meter setup to measure surface discharge: • Set the rotary switch to voltage ( ) setting. • Press the “DC/AC” button until “ ” appears on the display. • Press the “REC” button (selects the MAX.MIN.AVG function). • Insert the black lead in the “COM” jack. • Insert the red lead in the “ ” jack.

• Red test probe to the battery case around the positive (+) battery post: DO NOT TOUCH THE POST. A reading of more than 0.5V indicates excessive surface discharge. Clean the battery surface thoroughly if this has not been done and retest. If you continue to get a reading of more than 0.5V, the battery is defective and should be replaced. Battery No-Load Test A fully charged battery will display at least 12.6V. The following test checks for battery charge state. Since voltage tests only show the charge state and not the battery condition, you should also perform a load test to indicate the battery’s performance. CAUTION THE IGNITION SWITCH MUST BE OFF WHEN CONNECTING OR DISCONNECTING BATTERY CABLES TO PREVENT DAMAGE TO THE VEHICLE COMPUTER. Positive battery cable Negative battery cable Black Red 12V battery

• Set the rotary switch to voltage ( ) setting. • Press the “DC/AC” button until “ ” appears on the display. • Insert the black lead in the “COM” jack. • Insert the red lead in the “ ” jack. Turn the headlights on for 30 seconds to dissipate any battery surface charge. Disconnect the negative (-) battery cable from the negative battery terminal. Connect: • Black test probe to the negative (-) battery post. • Red test probe to the positive (+) battery post. Press the “REC” button (selects the MAX.MIN.AVG function). A minimum reading of less than 12.4V indicates an undercharged battery. Recharge before further testing. No Load 12V Battery Test Meter Reading % Battery Charge 12.60V or greater 100% 12.45V 75% 12.30V 50% 12.15V 25% Note: This table is only for non-critical reference. Battery Parasitic Load Test Each vehicle has a certain amount of parasitic load that is considered normal, but any current drain that exceeds that amount should be located and stopped. On newer vehicles after the introduction of electronic ignition and computer control systems, the parasitic load can be as high as 100mA. Check the manufacturer’s specifications for the acceptable level of parasitic load for a specific vehicle. WARNING DO NOT CRANK THE ENGINE OR TURN ON ACCESSORIES THAT DRAW MORE THAN 10A COMBINED DURING THIS TEST SINCE YOU COULD DAMAGE THE METER OR INJURE YOURSELF. CAUTION THE IGNITION SWITCH MUST BE OFF WHEN CONNECTING OR DISCONNECTING BATTERY CABLES TO PREVENT DAMAGE TO THE VEHICLE COMPUTER.

Meter setup to measure parasitic load: • Set the rotary switch to amps (10 ) setting. • Press the “DC/AC” button until “ ” appears on the display. • Insert the black lead in the “COM” jack. • Insert the red lead in the “A” jack. Turn the ignition switch and all accessories off. Disconnect the negative (-) battery cable from the negative battery terminal. Connect: • Black test probe to the disconnected negative (-) battery cable terminal. • Red test probe to the negative (-) battery post. Press the “REC” button (selects the MAX.MIN.AVG function). If excessive parasitic draw outside range specified in the vehicle’s service manual is indicated, remove the circuit fuses from the fuse box one at a time until the excessive draw is located. Also check non-fused applications such as headlights, computer relays, and capacitors in the instrument panel. NOTE: Many vehicle computers draw 10mA or more continuously. Turn off ignition and reconnect the battery.

This test checks the battery’s capacity to deliver sufficient cranking voltage. 12V Battery Red Black Meter setup to measure voltage load: • Set the rotary switch to voltage ( ) setting. • Press the “DC/AC” button until “ ” appears on the display. • Insert the black lead in the “COM” jack. • Insert the red lead in the “ ” jack. Connect: • Black lead to the negative (-) battery post. • Red lead to the positive (+) battery post. Press the “REC” button (selects the MAX.MIN.AVG function). Disable the ignition so that the engine can’t start and crank the engine for 15 seconds. Check the minimum reading. A reading of less than 9.40V at 60°F/16°C indicates a weak battery. Recharge or replace the battery before testing.

Meter Reading Battery/Air Temperature 10.0V 90°F/33°C 9.8V 80°F/27°C 9.6V 70°F/21°C 9.4V 60°F/16°C 9.2V 50°F/10°C 9.0V 40°F/4°C 8.8V 30°F/-1°C 8.6V 20°F/-7°C NOTE: The above table is only for non-critical reference. Battery temperature can be checked by using the meter’s temperature function. VOLTAGE DROP TESTS Voltage drop tests measure the amount of voltage expended to overcome resistance (an opposing force to the flow of electrical current created by a circuit or component); the lower the voltage drop reading, the less resistance in the circuit under test. The Hold function and the MAX/MIN Record function are very useful for measuring voltage drops on many different components and connections. For example, measuring the voltage drop across the connections and components in the starter circuit while cranking the engine (ignition or fuel system disabled to prevent starting) allows you to determine if there is excess resistance in the starter circuit. To measure voltage drop, current must be flowing in the circuit and both voltage test probes must be connected on the same side of the circuit. Voltage drop can also be determined from available voltage readings by noting the difference between each successive reading. Refer to the vehicle manufacturer’s specification for voltage drop information. If the voltage drop specification is not available, refer to the following table to determine typical voltage drop for 12V systems: Typical Allowable Voltage Drop Component Typical Voltage Drop Battery cable length up to 3 feet 0.1V Battery cable length over 3 feet 0.2V Magnetic switches 0.3V Solenoid switches 0.2V Mechanical switches 0.1V Battery cable connectors 0.05V Connections 0.0V

Normally, maximum voltage drop should not be more than 0.1V per wire, ground, connection, switch, or solenoid. You can determine the typical voltage by adding up the values from the above table. For example, the typical voltage drop from the negative battery post to the starter drive housing (negative test probe connected to the negative battery post and the positive test probe connected to the starter drive housing) should not exceed 0.4V. This connection consists of two connectors, one wire, and two grounds. If the voltage drop reading is within the allowable maximum voltage drop specification, the circuit’s resistance is acceptable. If the voltage drop reading exceeds the maximum allowable voltage drop, the point of excessive resistance can be located by checking the voltage reading at each connection and cable end. When a sharp decrease in voltage drop is observed, the cause of the excessive resistance is located between that test point and the previous test point. Battery Ground to Engine Block Voltage Drop Test This test checks for engine ground efficiency. Engine Block 12V Battery Red Black Setup to check voltage drop: • Set the rotary switch to voltage ( ) setting. • Press the “DC/AC” button until “ ” appears on the display. • Insert the black lead in the “COM” jack. • Insert the red lead in the “ ” jack. Touch the black test probe to the negative (-) battery post and the red test probe to the positive (+) battery post; this reading is the base voltage to compare your test voltage reading against.

Press the “REC” button (selects the MAX.MIN.AVG function). Disable the ignition so the engine can’t start and crank the engine for four to five seconds. This connection has two connectors, one wire, one ground and one cable terminal-to-battery post; a voltage drop of more than 0.5V indicates a poor ground circuit. Clean and inspect the battery cable connections and the ground connection and test again. NOTE: Repeat the test after the engine has thoroughly warmed up. Heat expansion may change voltage drop. Negative Chassis Ground Efficiency Voltage Drop Test This test checks for chassis ground efficiency. 12V Battery Red Black Engine Block Chassis Ground Meter setup to check voltage drop: • Set the rotary switch to voltage ( ) setting. • Press the “DC/AC” button until “ ” appears on the display. • Insert the black lead in the “COM” jack. • Insert the red lead in the “ ” jack. Touch the black test probe to the negative (-) battery post and the red test probe to the positive (+) battery post; this reading is the base voltage to compare your test voltage reading against.

• Red test probe to the point on the fender, fire wall, or vehicle frame where the accessory ground is fastened. Press the “REC” button (selects the MAX.MIN.AVG function). Turn on all the accessories (headlights, A/C fan, defroster, windshield wiper, etc.). Disable the ignition so the engine can’t start and crank the engine for four to five seconds. This connection has two connectors, one wire, one ground and one cable terminal-tobattery post; a voltage drop of more than 0.5V indicates a poor ground circuit. Clean and inspect the battery cable connections and the ground and test again. NOTE: Repeat the test after the engine has thoroughly warmed up. Heat expansion may change voltage drop. Battery Ground to Starter Solenoid (+) Voltage Drop Test This test checks for battery power efficiency to the starter solenoid. Measure the voltage drop between the battery post and the connecting cable, the solenoid post (+), and the wire that attaches to it. Red Black Solenoid 12V Battery Starter Motor Meter setup to check voltage drop: • Set the rotary switch to voltage ( ) setting. • Press the “DC/AC” button until “ ” appears on the display.

• Insert the red lead in the “ ” jack. Touch the black test probe to the negative (-) battery post and the red test probe to the positive (+) battery post; this reading is the base voltage to compare your test voltage reading against. Connect: • Black test probe direct to the positive (+) terminal on the starter solenoid. • Red test probe to the positive (+) battery post. Press the “REC” button (selects the MAX.MIN.AVG function). Disable the ignition so the engine can’t start and crank the engine for four to five seconds. This connection has two connectors and one wire; a voltage drop of more than 0.3V indicates a poor circuit. Clean and inspect the battery cable connections and ground and test again. NOTE: Repeat the test after the engine has thoroughly warmed up. Heat expansion may change voltage drop. Battery Ground to Complete Starter Circuit (+) Voltage Drop Test This test checks for battery power efficiency to the starter motor system including the starter solenoid. Even a very low resistance in the starter circuit can cause the starter to turn slowly because of the high currents in the starter circuits. Starter Motor Red Black Solenoid 12V Battery

• Set the rotary switch to voltage ( ) setting. • Press the “DC/AC” button until “ ” appears on the display. • Insert the black lead in the “COM” jack. • Insert the red lead in the “ ” jack. Touch the black test probe to the negative (-) battery post and the red test probe to the positive (+) battery post to establish the base voltage to compare the test voltage against. Connect: • Black test probe direct to the positive (+) terminal on the starter motor. • Red test probe to the positive (+) battery post. Press the “REC” button (selects the MAX.MIN.AVG function). Disable the ignition so the engine can’t start and crank the engine for four to five seconds. This connection has four connectors, two wires, and two solenoid connections; a voltage drop of more than 0.8mV indicates a poor circuit. Clean and inspect the battery, starter cables, solenoid, and cable connections and test again. A defective starter solenoid may cause an excessive voltage drop. Check the cables and connections before replacing the solenoid. NOTE: Repeat the test after the engine has thoroughly warmed up. Heat expansion may change voltage drop.

If you have successfully completed the battery tests and the voltage drops tests, you have verified that there is adequate battery voltage to the starter. Next, investigate how much current the starter is drawing by using a DC clamp-on current probe. Under normal operating conditions, with an outside air temperature of 70°F, a good rule of thumb for calculating cranking current is 1A per CID (Cubic Inch Displacement) or 60A per liter ± about 25%. Under no-load conditions, it’s 0.5A per CID ± about 10%. Check the manufacturer’s specifications for the correct starter cranking current. Starter Motor Red Black Meter setup to measure starter current: • Set the rotary switch to the millivolts DC (m ) setting. • Connect a DC clamp-on current probe (optional accessory) to the meter. Black lead to the “COM” jack and red lead to the “ ” jack. Clamp the clamp-on current probe around the cable connected to the positive (+) terminal of the starter motor. Be sure that the arrow on the clamp is pointed in the direction of the current flow in the cable. Press the “REC” button (selects the MAX.MIN.AVG function). The minimum reading is the negative current draw. Disable the ignition so the engine can’t start and crank the engine for four to five seconds. If the current draw is not high and the battery has tested good in the previous tests but the starter turns the engine slowly, check the resistance (or voltage drop) in the starter circuit again.

Charging system problems are often indicated by a “no-start” complaint. Normally, the battery has discharged and the starter will not crank the engine. To properly check the charging system, the battery must be fully charged. Recharge the battery completely if necessary, before continuing. To diagnose and adjust regulators/alternators on a typical GM vehicle, you must first determine if the system has an integral (internal) regulator. Then determine whether it is a type A or B alternator. The type A alternator has one brush connected to the battery (+) and the other brush grounded through the regulator. The type B regulator has one brush tied to ground and the other connected to the battery (+) through the regulator. Next isolate the problem to either the alternator or regulator. To do this, you need to by-pass the regulator (this is called “full fielding “), ground the type A field terminal, or connect the type B field terminal to the battery (+) side. If the system now charges, the regulator is faulty. Alternator Output Voltage Test at the Battery (+) This test checks for alternator output voltage to the battery. WARNING WHEN PERFORMING THIS TEST, IDLE THE ENGINE WITH THE LIGHTS ON SO THE OUTPUT VOLTAGE DOES NOT GO OVER 15V. IF CHECKING AN ALTERNATOR WITH AN INTEGRAL REGULATOR, YOU MUST KNOW WHICH TYPE YOU ARE TESTING TO AVOID ANY DAMAGE TO THE ALTERNATOR OR REGULATOR (SEE PREVIOUS DISCUSSION). Red Black 12V Battery Engine Block

• Set the rotary switch to voltage ( ) setting. • Press the “DC/AC” button until “ ” appears on the display. • Insert the black lead in the “COM” jack. • Insert the red lead in the “ ” jack. Turn all vehicle accessories off. Connect: • Black lead to the negative (-) battery post. • Red lead to the positive (+) battery post. Press the “REC” button (selects the MAX.MIN.AVG function). Start the engine and run it at 2,000 RPMs. A reading of 13.5V to 15.5V is an acceptable charging rate. If the voltage is low, check for: • Defective alternator or regulator (see tests that follow) • Cracked, glazed, or loose drive belt • Faulty or loose wires or connectors Alternator Output (+) Voltage Test (Loaded) This test is necessary only if the vehicle failed the previous test. Red Black 12V Battery Alternator Output (by-passed regulator)

• Set the rotary switch to voltage ( ) setting. • Press the “DC/AC” button until “ ” appears on the display. • Insert the black lead in the “COM” jack. • Insert the red lead in the “ ” jack. Press the “REC” button (selects the MAX.MIN.AVG function). Connect: • Black test probe to the negative (-) battery post. • Red test probe to the battery (+) terminal on the back of the alternator. Start the engine and run it at 2,000 RPMs. A reading of 13.5V to 15.5V is an acceptable charging rate. A good alternator will maintain at least 13.6V at the rated current output. Alternator Field Current Test Corroded or worn brushes (or terminals) limit the alternator’s field current and cause a low alternator output current. To check the field current, load the alternator to the rated output current with a battery load tester and measure the field current by using a DC clamp-on current probe (optional accessory) or use the “A” input jack on the meter. Red Black 12V Battery Positive Alternator Cable Meter setup to measure alternator field current: • Set the rotary switch to amps (10 ) setting. • Press the “DC/AC” button until “ ” appears on the display. • Insert the black lead in the “COM” jack. • Insert the red lead in the “A” jack. Turn all vehicle accessories off.

• Red test probe to the positive (+) alternator cable. Start the engine and run it at 2,000 RPMs. The current reading should be from 3A to 7A. NOTE: Low battery voltage produces a higher current. Alternator Diode Test The diode pack in an alternator consists of two diodes in series. To test the alternator diodes, remove the diode pack from the alternator. Then touch one test probe to one side of the alternator diode pack and touch the other test probe to the other side. Record the reading; then reverse the test probes and repeat the test. For one of the diode tests, the meter should display the voltage drop across the series diodes at typically about 0.8V; testing in the other direction should display OFL (OverFLow). If the reading is about 0.4V, one diode is shorted. A reading below 0.2V indicates two shorted diodes. NOTE: Shorted diodes in the alternator can cause a low current output and run the battery dead overnight. Red Black Anode Cathode Diode Pack Meter setup to measure voltage drop of the alternator diode pack: • Set the rotary switch to diode test ( ) setting. • Insert the black lead in the “COM” jack. • Insert the red lead in the “ ” jack. Disconnect the battery cable from the alternator output terminal. Dismantle the alternator and remove the diode pack from the alternator.

• Red test probe to the positive (anode) side of the diode pack. If neither diode is shorted, about 0.8V should be displayed. If one diode is shorted, about 0.4V should be displayed. If wire is open, both diodes are open, or the voltage drop is above 2V, OFL (OverFLow) should be displayed. IGNITION SYSTEM TESTS If you suspect a bad ignition wire, test resistance of the wire while moving, twisting, or bending the wire. The resistance values will typically be around 10kΩ per foot. If you suspect a problem with the ignition coil, check the resistance of the ignition coil’s primary and secondary windings. This test needs to be done both when the coil is hot and when it is cold. You should also measure from the coil’s case to each connector and between the primary and secondary windings to insure they are not shorted together. The primary windings should have a very low resistance – typically from a few tenths of an ohm to a few ohms. The secondary windings should have a much higher resistance – typically in the 10kΩ range. To get the actual figures for a specific coil, check the manufacturer’s specifications. Spark Plug Wire (Secondary Ignition Wire) Resistance Test WARNING TO AVOID ELECTRICAL SHOCK, ALWAYS DISCONNECT THE IGNITION COIL FROM THE IGNITION SYSTEM BEFORE TESTING. If spark plugs are more than two years old or if there are other indications of ignition system problems, check the spark plug wires. NOTE: Be careful when pulling the spark plug boot from the insulator as bonding may have occurred. This test checks for high resistance or open circuits in the secondary ignition wires (spark plug wires).

• Set the rotary switch to resistance (Ω ) setting. • If “ ” is present on the display, press the “DWL” button until “ ” disappears. • Insert the black lead in the “COM” jack. • Insert the red lead in the “ ” jack. Connect: • Test probes to opposite ends of the spark plug wire. Press the “REC” button (selects the MAX.MIN.AVG function). The reading is dependent on the length of the wire you are measuring. Typical measurements are approximately 10kΩ per foot of wire. For example, two feet of spark plug wire should measure about 20kΩ . Compare readings to other spark plug wires on the same engine to insure accuracy of the test. NOTE: Be sure the test probe tips make contact with the center conductor of the wire.

This test checks for resistance in the primary windings of conventional and DIS (distributorless) ignition coils. Red Red Black Black GM DIS Ignition Coil (TYPE II) Conventional Ignition Coil Meter setup to measure resistance in the primary windings of ignition coils: • Set the rotary switch to resistance (Ω ) setting. • If “ ” is present on the display, press the “DWL” button until “ ” disappears. • Insert the black lead in the “COM” jack. • Insert the red lead in the “ ” jack. Disconnect the coil from the ignition system. Connect: • Black test probe to the negative (-) terminal on the coil. • Red test probe to the positive (+) terminal on the coil. NOTE: Both primary connections are located on the back of Type II coils.

To get the actual figures for a specific coil, check the manufacturer’s specifications. NOTE: Test the ignition coil both when it is hot and when it is cold. Secondary Windings Resistance Test This test checks for resistance in the secondary windings of the conventional and DIS (Distributorless Ignition System) ignition coils. Red Red Black Black GM DIS Ignition Coil (TYPE II) Conventional Ignition Coil Meter setup to measure resistance in the secondary windings of ignition coils: • Set the rotary switch to resistance (Ω ) setting. • If “ ” is present on the display, press the “DWL” button until “ ” disappears. • Insert the black lead in the “COM” jack. • Insert the red lead in the “ ” jack. • Disconnect the coil from the ignition system. Connect: • Black test probe to the high-tension terminal on the coil. • Red test probe to the positive (+) terminal on the coil. Typical measurements are between 6kΩ and 20kΩ.

NOTE: Test the ignition coil both when it is hot and when it is cold. Condensers/Capacitors Leakage Test This meter can be used to check automotive condensers (capacitors) using the Resistance function. Since the Resistance function applies a voltage across the test leads, the condenser charges up and the displayed resistance increases to infinity. Any other reading indicates that you should replace the condenser. CAUTION BEFORE PERFORMING THIS TEST, MAKE SURE THAT IGNITION SYSTEM IS OFF AND ALL WIRES CONNECTED TO THE COILS ARE DISCONNECTED. Condenser Red Black Meter setup to check condenser leakage: • Set the rotary switch to resistance (Ω ) setting. • If “ ” is present on the display, press the “DWL” button until “ ” disappears. • Insert the black lead in the “COM” jack. • Insert the red lead in the “ ” jack. Connect: • Black test probe to the negative (-) side of the condenser. • Red test probe to the positive (+) side of the condenser.

from zero to infinity over a short period of time. NOTE: In a conventional ignition system, make sure that the points are open before starting the test. Switch the test leads and check the condenser in both directions. Check condensers under both hot and cold conditions. The meter’s capacitance measurement function can be used to measure the capacitance of condensers. POSITION SENSORS There are basically two types position sensors: Magnetic and Hall-Effect. The magnetic type is simply a permanent magnet with a coil of wire wrapped around it. Magnetic sensors have two wires – one connected to each end of a coil winding. Magnetic sensors can be found in some distributors and consist of a magnetic pickup and a reluctor to change the magnetic field. In a distributor, the clearance between the pickup and the reluctor on a magnetic sensor is critical; be sure to check according to the manufacturer’s specifications. The specs are usually between 0.03 inches and 0.07 inches. A Hall-Effect sensor uses a semiconductor material that produces a voltage as a magnetic field passes through it. The voltage produced by the Hall-Effect sensor is proportional to the strength of the magnetic field. This magnetic field can come from a permanent magnet or an electric current. Hall-Effect position sensors have replaced ignition points in many distributor type ignition systems. They are also currently being used to determine the crank and cam position on distributorless ignition system (DIS), which tells the vehicle’s computer when to fire the coils. This position information also tells the computer when to open the injectors on sequential fuel injected systems.

This test checks for pulses from a magnetic distributor pickup to determine if the reluctor wheel or the magnetic pickup is bad. Red Reluctor Magnetic Pickup Coil Black Meter setup to check pulses from a magnetic pickup: • Set the rotary switch to voltage ( ) setting. • Press the “DC/AC” button until “ ” appears on the display. • Insert the black lead in the “COM” jack. • Insert the red lead in the “ ” jack. Disconnect the distributor from the ignition module. Connect: • Test probes to the sensor output leads. Watch the bargraph change. When the engine is cranked, pulses should appear on the bar graph. No pluses will appear if the reluctor wheel or the magnetic pickup is bad. NOTE: Clearance between the pickup and the reluctor is very critical. Be sure to check it according to the manufacturer’s specifications. On GM cars, remove the distributor cap to access the pickup and the reluctor.

This test checks for switching action of the Hall-Effect position sensor. Red Fixed position magnet Signal output (+12V) Hall-Effect device Switching transistor Insert a thin metal blade between Hall- Effect device and magnet Connect to battery Black Meter setup to check Hall-Effect sensors: • Set the rotary switch to voltage ( ) setting. • Insert the black lead in the “COM” jack. • Insert the red lead in the “ ” jack. Connect: • Black test probe to the ground terminal of the Hall-Effect sensor. • Red test probe to the signal output terminal of the Hall-Effect sensor. Insert a thin metal blade or steel feeler gauge between the Hall-Effect device and the magnet while watching the bargraph and the display. The output signal should vary from 12V to 0V. Inserting the metal blade blocks the magnetic field from getting to the Hall-Effect sensor; removing the metal blade allows the magnetic field to reach the sensor.

Computer Controlled Systems Most cars built today have several on-board computers that control the engine, transmission, brake, suspension, climate control, entertainment, and many other systems. Control systems of computerized vehicle are made up of the following three basic component groups: • Sensors. Input devices to provide feedback for the vehicle computer. For example, coolant sensor, vacuum sensor, throttle position sensor, RPM senor, barometric sensor, oxygen sensor, etc. • Engine Control Module (ECM). Processes feedback supplied by the sensors and then sends an electronic command to the relevant component actuators. • Actuators. Output devices that may be mechanical, electrical, or vacuum components activated by the vehicle computer. For example, electro-mechanical carburetor, fuel injector, ignition spark advancer, air pump, exhaust gas recirculation valve, canister purger, torque converter clutch, etc. Sometimes when a sensor or actuator fails, an error code is generated. These errors are stored in the computer memory as fault or trouble codes. Each sensor has various code numbers assigned to it, depending on the problem that occurred. When a fault occurs, a technician can read the fault codes by retrieving the information from the computer’s memory. There are various ways to read these trouble codes. On vehicle model years 1995 or older, they may display the fault codes using the digital clock on the dash, others use the tachometer, and many use a blinking light to signal the fault codes. However, vehicle model years 1996 or newer which use the OBD II protocol require a code reader or scan tool that plugs into the computer’s serial communication port to read the trouble codes. NOTE: For specific instructions on how to retrieve trouble codes from a specific vehicle computer system, consult the service manual for the vehicle. Basic Component Testing Testing with specific components often requires detailed component schematics and test specifications provided by the vehicle manufacturer. The following section provides general test information and procedures for the primary input devices (sensors) and output devices (actuators).

Temperature Tests To test many components (such as radiators, transmissions, heaters, A/C condensers, A/C evaporators, engine coolant sensors, coolant temperature switches, and air temperature sensors) that regulate temperature, measure the surface temperature of the area surrounding the component. Radiator K type Thermocouple Meter setup to measure temperature: • Set the rotary switch to temperature (TEMP) setting. • Insert the plug of the K type thermocouple into the “COM” and “ ” jacks as shown, make sure that the polarity connections are correct. • Press the “REC” button (selects the MAX.MIN.AVG function). Touch the tip of the thermocouple directly to the surface area near the radiator inlet. Press the “DC/AC” button to switch between °F and °C. Refer to the manufacturer’s specifications for correct temperature. Measured temperature should be within ±10°F (±5°C) of the specifications. NOTE: The above procedure is specific to testing radiator temperature. Use similar test procedures to measure temperature of other components or systems. Two-Wire Device (Thermistor) Tests Thermistors are essentially variable resistors that are sensitive to temperature level changes. The thermistor’s resistance value changes as the temperature changes. Typical thermistor applications are: Engine Coolant Temperature (ECT) sensor, Air Charge Temperature (ACT) sensor, Manifold Air Temperature (MAT) sensor, Vane Air Temperature (VAT) sensor, and Throttle Body Temperature (TBT) sensor, etc. A thermistor can be tested by checking resistance change or voltage change. A quel de Evaick and easy way to monitor change is with the bargraph on the meter.

Black Red Meter setup to check resistance change of thermistors: • Set the rotary switch to resistance (Ω ) setting. • If “ ” is present on the display, press the “DWL” button until “ ” disappears. • Insert the black lead in the “COM” jack. • Insert the red lead in the “ ” jack. Disconnect the sensor connector. Connect: • Black test probe to the negative (-) terminal of the sensor. • Red test probe to the positive (+) terminal of the sensor. Resistance reading should match the temperature of the sensor. NOTE: Refer to the manufacturer’s specifications for resistance vs temperature for the sensor. Temperature can be checked using the previous procedure.

Black Red Meter setup to measure voltage change of a thermistor: • Set the rotary switch to voltage ( ) setting. • Press the “DC/AC” button until “ ” appears on the display. • Insert the black lead in the “COM” jack. • Insert the red lead in the “ ” jack. • Press the “REC” button (selects the MAX.MIN.AVG function). Disconnect the sensor connector. Connect jumper wires between the connector and the sensor. Connect: • Black test probe to the negative (-) circuit from the sensor. • Red test probe to the circuit coming from the power source. Start the engine. The voltage should change as the temperature changes. Refer to the manufacturer’s specifications. If the voltage change is not within specifications, check for sources of excessive resistance before replacing thermistor: poor connectors, connections, or breaks in the wiring. NOTE: Temperature can be checked using the meter’s temperature measurement function.

A potentiometer is a variable resistor. The signal generated is used by the vehicle computer to determine the position and direction of movement of a device within the component. Typical potentiometer applications are: Throttle Position Sensor (TPS), Exhaust Gas Recirculation Valve Position Sensor (EGR), and Vane Air Flow Meter (VAF), etc. An analog Throttle Position Sensor (TPS) is found on many vehicles. The TPS informs the vehicle computer of the following: • Throttle opening • Whether and how fast the throttle is opening • Whether and how fast the throttle is closing • When the throttle is wide open • When the throttle is at idle One of its most important functions is to tell the computer that the throttle is opening. It replaces the accelerator pump found on carbureted engines, stopping the engine from stumbling when the throttle is opened quickly. When that happens, manifold absolute pressure (MAP) quickly rises (vacuum drops), causing vaporized gasoline to condense on the manifold walls. Since there is less fuel available to the cylinders, more fuel must be added to the air stream. Another important function is to tell the computer that the throttle is closing. To maintain acceptable emissions, the computer must lean out the mixture when MAP drops (vacuum rises). For best fuel economy, the computer completely shuts off fuel in some engines when vacuum is high and the throttle is at idle. Therefore, the computer must know when the throttle is at idle. Throttle position information is a variable resistance from a potentiometer attached to the throttle shaft. Wide- open-throttle and throttle-closed signals come from switches attached to the TPS. The TPS is really just a potentiometer or variable resistor. As you sweep the throttle, the resistance changes. As its resistance changes, so does the voltage signal returning to the computer. The TPS can be tested either by watching the voltage change or by watching the resistance change, using the bargraph on the meter.

Red Black Jumper Wires TPS Connector 5V Supply Ground Signal Meter setup to check resistance change: • Set the rotary switch to resistance (Ω ) setting. • If “ ” is present on the display, press the “DWL” button until “ ” disappears. • Insert the black lead in the “COM” jack. • Insert the red lead in the “ ” jack. • Press the “REC” button (selects the MAX.MIN.AVG function). Disconnect the sensor connector and connect jumper wires between the connector and the sensor. Connect: • Black test probe to the ground circuit. • Red test probe to the signal line (refer to the manufacturer’s schematic) Rotate the TPS by moving the throttle and watch the bargraph move as the TPS turns. The resistance reading should change as the signal arm on the TPS is moved (signal sweep). As you rotate the TPS to change resistance, the bargraph moves smoothly if the TPS is good and moves erratically if it is bad. NOTE: Do not insert the test probe tips into the TPS as they may damage the smaller type plug on the TPS connector.

Red Black Jumper Wires TPS Connector 5V Supply Ground Signal Meter setup to check voltage change: • Set the rotary switch to voltage ( ) setting. • Press the “DC/AC” button until “ ” appears on the display. • Insert the black lead in the “COM” jack. • Insert the red lead in the “ ” jack. • Press the “REC” button (selects the MAX.MIN.AVG function). Disconnect the sensor connector and connect jumper wires between the connector and the sensor. Connect: • Black test probe to the ground circuit. • Red test probe to the signal line. Turn the ignition key on; do not start the engine. Rotate the TPS by moving the throttle and watch the bargraph move. The volatge drop should change as the position of the signal arm on the TPS moves (signal sweep). The bargraph should increase smoothly without jumping if the TPS is good. Refer to the manufacturer’s specifications. If the voltage change is not within the specifications, check for sources of excess resistance before replacing potentiometer: poor connectors, connections, or breaks in the wiring.

connector. Oxygen (O2) Sensor Test The Oxygen (Lambda) Sensor samples the amount of oxygen (O2) in the exhaust stream. The O2 sensor produces an output voltage that is a direct ratio to the oxygen level in the exhaust stream. The vehicle computer uses this signal to change the air/fuel mixture ratio. This test checks the signal output voltage levels of the O2 sensor. O2 Black Red Sensor Signal Output Voltage Wire Good Ground Exhaust Manifold Meter setup to measure signal output voltage of the oxygen sensor: • Set the rotary switch to voltage ( ) setting. • Press the “DC/AC” button until “ ” appears on the display. • Insert the black lead in the “COM” jack. • Insert the red lead in the “ ” jack. • Press the “REC” button (selects the MAX.MIN.AVG function). Connect: • Black test probe to a good quality ground. • Red test probe to the signal output voltage wire. NOTE: Be careful not to burn yourself on the hot exhaust manifold. Run the engine at a fast idle (2,000 RPMs) for a few minutes. The O2 voltage readings should sweep between 100mV (lean) and 900mV (rich). Once the O2 sensor reaches operating temperature, the DC voltage reading should begin to sweep. Under varying operating conditions, the O2 voltage will rise and fall, but usually averages around 0.45V dc.

Recommended electrical test procedures for pressure sensors such as Manifold Absolute Pressure (MAP) and Barometric Pressure (BP) vary greatly depending upon type and manufacturer. Refer to the vehicle manufacturer’s service manual for the schematics, specifications, and test procedures. Analog Type Pressure Sensor. Analog sensor can be tested using the voltage tests described for 3-wire potentiometer. Use a vacuum pump to vary the pressure on the sensor in place of sweeping the sensor. Digital Type Pressure Sensor. A digital sensor can be tested by using the frequency (Hz) function of the meter with the same series of tests suggested for 3-wire potentiometer voltage tests. Use a vacuum pump to vary the pressure on the sensor in place of sweeping the sensor. In all cases, refer to the vehicle manufacturer’s service manual for the correct testing procedures. NOTE: Resistance tests are impossible for pressure sensors because all pressure sensors have voltage or frequency output. Output Device (Actuator) Tests The electrical tests for output devices varies depending upon type and manufacturer. Consult the vehicle manufacturer’s service manual for the schematics, specifications, and test procedures. Primary output devices generate a form of electromagnetic ON/OFF signal, which will generally be one of the following three signals: • On or Off only (e.g., switches) To check an on/off device such as a switch, perform continuity tests with the switch in the on and off position. • Pulse width (e.g., fuel injectors) Pulse width is the length of time an output device (actuator) is energized. To check fuel injectors, measure the On time using the pulse width measurement function. • Duty cycle (e.g., mixture control solenoid) Duty cycle (or duty factor) is the percentage of time a signal is above or below a trigger level during one cycle. The amount of On time is measured as a percentage of the total On/Off cycle. To check a mixture control solenoid, measure the percent of high (+) or low (-) time in a duty cycle. In most cases of automotive electronics, the low (-) time is the On time.

Electrical System Tests Automotive Systems and Components Measurement Type Voltage Presence and Level Voltage Drop Current (Amps) Resistance (Ohms) Frequency (Hz) Charging System Alternators    Connectors    Diodes   Regulators   Cooling System Connectors    Fan Motors    Relays    Temperature Switches    Ignition System Coils   Condensers   Connectors    Contact Set (points)   MAF Sensors   Magnetic Pickup    MAP/BP Sensors   O2 Sensors   Starting System Batteries   Connectors   Interlocks  Solenoids    Starters   

     Condensers (Capacitors)      Connectors        Contacts Set        Distributor Cap  Engine Speed  Feedback Carburetors       Fuel Injectors (Electronic)        Hall-Type Sensors         Idle Air Motors          Ignition Modules     MAF Sensor    Magnetic Pickups         MAP & BP Sensors     O2 Sensors     Throttle Position Sensors      STARTING SYSTEM Battery     Connectors       Interlocks (neutral safety switch)     Solenoids        Starters        COOLING SYSTEM Connectors       Fan Motor     Radiator   Relays      Temperature Sensors    Temperature Switches      

   Diode Rectifier    Regulators      BODY ELECTRIC Compressor Clutch      Lighting Circuits    Relay and Motor Diodes  Transmissions    * Used with a DC current probe

Crest Factor: < 3 : 1 Accuracy specifications take the form of: ±([% of Reading]+[number of Least Significant Digits]) DC Voltage Range Resolution Accuracy 400mV 0.1mV ± (0.3% + 2) 4V 0.001V 40V 0.01V 400V 0.1V 1,000V 1V ± (0.75% + 3) Input Impedance: Ω AC Voltage Range Resolution Accuracy 50Hz - 60Hz 45Hz - 1kHz 4V 0.001V ± (0.75% + 3) ± (2.5% + 5) 40V 0.01V 400V 0.1V 750V 1V ± (0.75% + 5) Input Impedance: Ω Display: True-RMS About 10M About 10M

4,000µA 1µA 40mA 0.01mA ± (0.8% + 3) 400mA 0.1mA 4A 0.001A ± (1.5% + 5) 10A 0.01A AC Current Range Resolution Accuracy 400µA 0.1µA ± (0.8% + 1) 4,000µA 1µA 40mA 0.01mA ± (1.2% + 5) 400mA 0.1mA 4A 0.001A ± (2.0% + 5) 10A 0.01A Display: True rms Frequency Range: 45Hz - 1kHz Resistance Range Resolution Accuracy 400Ω 0.1Ω ± (0.5% + 10) 4kΩ 0.001kΩ 40kΩ 0.01kΩ ± (0.5% + 3) 400kΩ 0.1kΩ 4MΩ 0.001MΩ ± (1.5% + 10) 40MΩ 0.01MΩ Open Circuit Voltage: < 3V dc

voltage drop of the diode is shown on the display. Open Circuit Voltage: about 3V dc Test Current: about 0.24mA Continuity Test Description Remark The buzzer will sound when the resistance is less than about 40Ω. The buzzer will not sound when the resistance is more than 150Ω. The buzzer may or may not sound when the resistance is between 40Ω and 150Ω. Open Circuit Voltage: about 3V dc Capacitance Range Resolution Accuracy 1µF 0.001µF ± (2.0% + 5) 10µF 0.01µF 100µF 0.1µF ± (3.0% + 5) 1,000µF 1µF ± (5.0% + 5) Note: Accuracy is for capacitors that have negligible dielectric absorption. Temperature Range Resolution Accuracy -40°C to 0°C 0.1°C ± (4.0°C + 3 digits) 0°C to 400°C 0.1°C ± (2% + 3°C) 1°C ± 3.0% of reading -40°F to 0°F 0.1°F 0°F to 400°F 0.1°F ± (2% + 5.4°F) 400°F to 2,498°F 1°F ± (7.2°F + 3 digits) Use K type thermocouple. Note: 1. Accuracy does not include error of the thermocouple probe. 2. Accuracy specification assumes ambient temperature is stable to ±1°C. For ambient temperature changes of ±5°C, rated accuracy applies after 1 hour. ± 3.0% of reading

Range Resolution Accuracy 200Hz 0.01Hz ± (0.05% + 2) 2,000Hz 0.1Hz 20kHz 0.001kHz 200kHz 0.01kHz Minimum Frequency: 0.5Hz Sensitivity: 250mV RPM IP Range Resolution Accuracy 30 - 9,000RPM 1RPM ± (0.5% + 2) 7 selectable trigger levels and ± trigger slopes RPM IG Range Resolution Accuracy 60 - 12,000RPM 1RPM ± (0.5% + 2) 7 selectable trigger levels and ± trigger slopes 9 Selectable Cylinder Numbers: 1, 2, 3, 4, 5, 6, 8, 10, 12 Duty Cycle Range Resolution Accuracy 0.0% - 99.9% 0.1% ± (0.2%/kHz + 1) Pulse Width: > 2µs 7 selectable trigger levels and ± trigger slopes

0.1° ± (1.2°/krpm + 2) Pulse Width: > 2µs 7 selectable trigger levels and ± trigger slopes 9 Selectable Cylinder Numbers: 1, 2, 3, 4, 5, 6, 8, 10, 12 *1 Measurement range can vary with engine RPM and trigger slope. Pulse Width Range Accuracy 0.1ms - 1999.9ms ± (0.5% + 1) Pulse Width: > 2µs 7 selectable trigger levels and ± trigger slopes Frequency (Automotive Hz) Range Resolution Accuracy 200Hz 0.01Hz ± (0.5% + 2) 2,000Hz 0.1Hz Minimum Frequency: 0.5Hz 7 selectable trigger levels and ± trigger slopes

Display (LCD): Digital: Counts – 4,000 (frequency range: 20,000) Updates – 1 time/sec in RPM, FREQ, Duty Cycle, Dwell, and Pulse Width; 3 times/sec in all other functions Analog: 2×41 segments Updates – 20 times/sec Fuse Protection: mA or µA: 1,000V/500mA FAST fuse, Min. Interrupt Rating 10,000A A: 1,000V/10A FAST fuse, Min. Interrupt Rating 10,000A IP Degree: IP20 Storage Temperature: -20°C to 60°C (-4°F to 140°F) Operating temperature: 0°C to 45°C (32°F to 113°F) Relative Humidity: 0% to 80% (0°C to 35°C; 32°F to 95°F) 0% to 70% (35°C to 45°C; 95°F to 113°F) Temperature Coefficient: 0.15 × (specified accuracy)/°C (< 18°C or > 28°C; < 64°F or > 82°F) Battery: 9V battery, 6F22 or equivalent, 1 piece Size: 209 × 117.5 × 70 mm Weight: About 637g (including battery)

Use the following procedure to clean the terminals: 1. Set the rotary switch to OFF position and remove all test leads from the meter. 2. Shake out any dirt which may exist in the terminals. 3. Soak a new swab with alcohol. 4. Work the swab around in each terminal. If you will not use the meter in a period of more than 60 days, remove the battery and store it separately. Replacing Battery and Fuse WARNING TO AVOID ELECTRICAL SHOCK OR PERSONAL INJURY, REMOVE THE TEST LEADS AND ANY INPUT SIGNAL BEFORE REPLACING BATTERY OR FUSE. TO PREVENT DAMAGE OR INJURY, INSTALL ONLY FUSES WITH THE RATINGS SPECIFIED. TO AVOID FALSE READINGS, WHICH COULD LEAD TO POSSIBLE ELECTRIC SHOCK OR PERSONAL INJURY, REPLACE THE BATTERY AS SOON AS THE LOW BATTERY INDICATOR ( ) APPEARS. To replace the battery: 1. Set the rotary switch to the “OFF” position and remove all test leads from the meter. 2. Remove the screw on the battery cover and remove the battery cover. 3. Replace the old battery with a new one of the same type. 4. Reinstall the battery cover and the screw. To replace the fuse: 1. Set the rotary switch to the “OFF” position and remove all test leads from the meter. 2. Remove the screw on the battery cover and remove the battery cover. 3. Remove the screws on the back cover and move the back cover aside gently. 4. Replace the blown fuse with a new one of the same ratings. 5. Reinstall the back cover and its screws. Then reinstall the battery cover and its screw. This meter uses two fuses: F1: 1,000V/500mA FAST fuse, Ø6.35X32mm, Min. Interrupt Rating 10,000A F2: 1,000V/10A FAST fuse, Ø10X38mm, Min. Interrupt Rating 10,000A

Place the supplied CD on the tray of the CD-ROM drive of your PC and close it. Locate the “EM721.exe” file in the “EM721-PC” folder on the CD, and double-click this file to run this communication software. Connect the supplied USB data line to the USB port on the top of the meter, and connect the other end of this USB data line to a USB port on your PC. Turn on the meter. Then press and hold down the “REL” button on the meter for about 1 second to turn on the USB communication function; “ ” will appear on the meter screen as an indication. (NOTE: After you finish using the USB communication function, turn off this function to save battery power by pressing and holding down this “REL” button for about 1 second.) Run the communication software, the following EM721-PC interface will appear: Readings transferred from the meter will appear here. Buttons Click the “COMSETTING” button, the Serial-Port Debug Assistant interface will appear.

which is being used by the meter. Then click the “Open” button on this interface, the “Open” button will change into “Close” button. Hexadecimal Codes hexadecimal code display area Serial port drop-down list box " Open " Button Serial-Port Debug Assistant interface “COMSETTING” button

display area on the upper left area of the M721-PC interface will show readings of the meter in almost a realtime mode. Close the Serial-Port Debug Assistant interface by clicking the “ ” button at the top right corner of the Serial-Port Debug Assistant interface. Now the meter has been successfully connected to the PC. (Clicking the “Close” button on the Serial-Port Debug Assistant interface will stop the data transfer from the meter to the PC.) The eight buttons on the left half of the EM721-PC interface correspond to the buttons on the meter, respectively. You can use these buttons of the interface in the same way you use the buttons on the meter, but the “REL” button on the interface can not be used to turn on or off the USB communication function of the meter. To turn on or off the USB communication function of the meter, press and hold down the “REL” button on the meter for 1 sec. In addition, the rotary switch on the left half of the interface is not functional and can not be used. This rotary switch is not functional. Readings transferred from the meter appear in the table here.

2. COMSETTING Button - - - Used to display the Serial-Port Debug Assistant interface 3. “MIN” Box - - - Automatically shows the minimum reading of all readings being listed in the table on the “Data Logging” tab. 4. “MAX” Box - - - Automatically shows the maximum reading of all readings being listed in the table on the “Data Logging” tab. 5. “AVG” Box - - - Automatically shows the average reading of all readings being listed in the table on the “Data Logging” tab. 6. “Data Logging” Tab - - - Used to display transferred data in table. “Clear” Button - - - Used to clear all the data being listed in the table on the “Data Logging” tab. “Save” Button - - - Used to save the data being listed in the table on the “Data Logging” tab as a file. “Data Len” Spin Edit Box - - - Used to set the max. number of records that can be displayed in the table on the “Data Logging” tab. 7. “Draw Graph” Tab - - - Used to show the plot of the readings being listed in the table on the “Data Logging” tab. “unit” Drop-down List Box - - - Used to select a desired unit for the Y-axis.

2. Our company will not take the other responsibilities for any loss. 3. The contents of this manual can not be used as the reason to use the meter for any special application. DISPOSAL OF THIS ARTICLE Dear Customer, If you at some point intend to dispose of this article, then please keep in mind that many of its components consist of valuable materials, which can be recycled. Please do not discharge it in the garbage bin, but check with your local council for recycling facilities in your area.

contact to one of our customer technicians. They will be more than happy to help with any service or warranty questions you may have about your digital multimeter. Mac Tools 505 North Cleveland Avenue Suite 200 Westerville, Ohio 43082 800.MACTOOLS MACTOOLS.COM

Para reducir el riesgo de lesiones, lea y comprenda estas advertencias e instrucciones de seguridad antes de usar la herramienta. Conserve estas instrucciones junto con la herramienta para consulta en el futuro. Si tiene alguna pregunta, póngase en contacto con su representante o distribuidor de MAC TOOLS. ADVERTENCIA Multímetro automotor Manual del usuario EM721

de un año. Nuestra obligación ante el comprador original se limitará a la reparación o el reemplazo, a nuestro costo (sin incluir los gastos de envío), de una herramienta defectuosa, si dicho comprador original la devuelve en el plazo de un año desde la fecha de compra, con todos los gastos de envío prepagados. ESTA GARANTÍA NO CUBRE LOS DEFECTOS O LOS DAÑOS A LA HERRAMIENTA (i) después de que termina el período de garantía; (ii) que resulten del uso indebido o fuera de lo común; (iii) que resulten de un mantenimiento o un uso inadecuado de la herramienta; o (iv) que resulten de cualquier reparación o servicio de mantenimiento realizados por terceros que no sean Mac Tools. Esta garantía no cubre los elementos expansibles como baterías y/o fusibles. LIMITACIÓN DE LA RESPONSABILIDAD Este manual explica cómo utilizar el medidor para realizar pruebas de diagnóstico y encontrar posibles lugares de problemas electrónicos de automóviles. No le indica cómo corregir el problema. Una vez que haya localizado un problema, consulte el manual de servicio de su automóvil u otros manuales que suministren información específica necesaria para la reparación. Toda la información, ilustraciones, especificaciones contenidas en este manual se basan en la información más reciente disponible al momento de publicación. Se reserva el derecho de realizar cambios en cualquier momento sin previo aviso. ÍNDICE 1. Información de seguridad .................................................................. 86 2. Introducción .................................................................................... 89 3. Panel frontal .................................................................................... 90 4. Comprensión de la pantalla ............................................................... 96 5. Pruebas eléctricas y mediciones básicas ............................................ 99 6. Mediciones automotrices básicas ..................................................... 108 7. Pruebas básicas de diagnóstico automotor ........................................ 115 8. Pruebas básicas de componentes automotores .................................. 140 9. Resumen de las pruebas del sistema eléctrico automotor ................... 149 10. Especificaciones ............................................................................. 152 11. Especificaciones generales ............................................................. 157 12. Mantenimiento ............................................................................... 158 13. Instrucciones del software de comunicación entre medidor y PC ......... 159

Límites de mediciones: Tensión de CC 0.1 mV a 1000 V Tensión de CA 0.001 V a 750 V RPM IP 30 a 9000 RPM RPM IG 60 a 12000 RPM CC (Amperios) 0.1 µA a 10 A CA (Amperios) 0.1 µA a 10 A Resistencia (Ohmios) 0.1 a 40 MΩ Frecuencia (Hz) 0.5 Hz a 200 kHz % de ciclo de trabajo 0 a 99.9 % Permanencia (Grados) 0° a 356.4° Ancho de pulso (Milisegundos) 0.1 ms a 1999.9 ms Temperatura (Celsius/Fahrenheit) - 40 °C a +1370 °C (- 40 °F a +2498 °F) Capacitancia (Microfaradios) 0.001 µF a 999 µF Comprobación de continuidad Alarma sonora a aprox. < 40 Ω en el rango de 400 Ω

Este medidor se ha diseñado de acuerdo con la norma IEC 61010 en relación con instrumentos de medición electrónicos con una categoría de medición (CAT III 1000V) y grado de contaminación 2. ADVERTENCIA SIGA ESTOS LINEAMIENTOS PARA EVITAR POSIBLES LESIONES O DESCARGAS ELÉCTRICAS: • No use el medidor si está dañado. Antes de usar el medidor, revise la carcasa. Preste especial atención al aislamiento que rodea los conectores. • Revise los cables de prueba para verificar que no haya daños en el aislamiento ni metal expuesto. Compruebe los cables de prueba para determinar su continuidad. Reemplace los cables de prueba dañados antes de usar el medidor. • No use el medidor si no funciona con normalidad. La protección puede estar dañada. En caso de duda, repare el medidor. • No haga funcionar el medidor si hay gas, vapor o polvo explosivos (o inflamables). • No supere la tensión nominal, según lo indicado en el medidor, entre los terminales o entre cualquiera de ellos y la conexión a tierra. • Antes de su uso, verifique el funcionamiento del medidor mediante la medición de una tensión conocida. • Cuando realice la reparación del medidor, utilice solamente piezas de repuesto especificadas. • Tome precauciones al trabajar con tensiones superiores a 30 V CA RMS, máximo de 42 V o 60 V CC. • Estas tensiones representan un peligro de descarga eléctrica. • Cuando se utilizan las sondas, mantenga los dedos detrás de los protectores correspondientes en dichas sondas. • Al realizar las conexiones, conecte el cable de prueba común antes de conectar el cable de prueba vivo. • Cuando desconecte los cables de prueba, desconecte primero el cable de prueba vivo. • Quite los cables de prueba del medidor antes de abrir la cubierta de la batería o la carcasa. • No haga funcionar el medidor con la cubierta de la batería o partes de la carcasa extraídas o flojas. • Para evitar falsas lecturas, que podrían producir descargas eléctricas o lesiones personales, reemplace la batería en cuanto aparezca el indicador de batería baja ( ). • No use el medidor de un modo que no esté especificado en este manual. De lo contrario, las funciones de seguridad provistas por el medidor pueden verse afectadas. • Cuando mida corriente utilizando los cables de prueba, desconecte la alimentación al circuito antes de conectar el medidor al circuito. Recuerde colocar el medidor en serie con el circuito. • Para evitar descargas eléctricas, no toque ningún conductor sin aislamiento con la mano o la piel, y no se ponga a tierra usted mismo mientras esté utilizando el medidor. • Cumpla con los códigos de seguridad locales y nacionales. Debe usarse equipo de protección individual para evitar descargas eléctricas y lesiones por ráfaga de arco en los casos en que los conductores vivos estén expuestos. • Siga los requisitos correspondientes y el procedimiento de seguridad especificado en el Manual del usuario y en el Manual de servicio provisto por el fabricante del vehículo bajo prueba. • El gas de escape contiene monóxido de carbono que es inodoro, genera tiempos de reacción más lentos y puede provocar lesiones graves. Cuando realice la prueba del vehículo con el motor en funcionamiento, dicha prueba siempre debe realizarse en un área bien ventilada o con el venteo del gas de escape hacia el exterior del edificio. • Aplique el freno de estacionamiento y trabe las ruedas antes de probar o reparar el vehículo, a menos que se indique lo contrario. Es especialmente importante bloquear las ruedas de los vehículos con tracción delantera: el freno de estacionamiento no sujeta las ruedas motrices. El sistema de combustible o de encendido debe estar desactivado para realizar pruebas del sistema de arranque. • Use siempre gafas de seguridad cuando trabaje cerca de baterías. • No fume ni permita la presencia de llamas abiertas o chispas en el área de trabajo. Los humos de la gasolina y los gases producidos por la batería son muy explosivos. Mantenga cigarrillos, chispas y llamas abiertas alejados de las baterías en todo momento.

el cuerpo y la ropa de piezas del motor en movimiento o calientes en todo momento. • Especialmente en aplicaciones marinas con motores internos o internos/fuera de borda, asegúrese de que el área de trabajo esté bien ventilada. Haga funcionar el achique por lo menos cuatro minutos antes de arrancar el motor o hacer conexiones de los cables de prueba. • Siempre evite trabajar solo. • No use el medidor si este o su mano están húmedos. • Peligro restante: Cuando un terminal de entrada se conecta a un potencial vivo peligroso, se debe tener en cuenta que este potencial puede tener lugar en todos los demás terminales. • CAT III: La categoría de medición III es para las mediciones realizadas en instalaciones edilicias. Ejemplos de esta categoría son mediciones en tableros de distribución, disyuntores, cableado, incluidos cables, barras de distribución, cajas de empalme, interruptores, enchufes-tomacorrientes en la instalación fija y equipos para uso industrial y algunos otros equipos, por ejemplo, motores estacionarios con conexión permanente a la instalación fija. No use el medidor para mediciones dentro de las categorías de medición IV. PRECAUCIÓN PARA EVITAR POSIBLES DAÑOS AL MEDIDOR O AL EQUIPO BAJO PRUEBA, SIGA ESTOS LINEAMIENTOS: • Desconecte la alimentación del circuito y descargue todos los condensadores antes de probar la resistencia, los diodos, los condensadores, la temperatura y la continuidad. • Utilice los terminales adecuados en cuanto a función y rango para sus mediciones. • Antes de medir la corriente, compruebe los fusibles del medidor y desconecte la alimentación al circuito antes de conectar el medidor a dicho circuito. • Antes de girar el interruptor giratorio para cambiar de función, desconecte los cables de prueba del circuito bajo prueba.

Precaución, riesgo de peligro, consulte el manual de operación antes de usar. Precaución, riesgo de descarga eléctrica. Terminal de puesta a tierra Fusible Cumple con las directivas de la Unión Europea El equipo se encuentra completamente protegido con aislamiento doble o aislamiento reforzado.

Este manual del usuario le indica cómo utilizar el medidor. También puede necesitar un manual que proporcione información técnica sobre el vehículo que planea probar. Los recursos de información más importantes son los manuales de servicio de reparación del vehículo que, por lo general, pueden comprarse a través de concesionarios automotores. También están disponibles a través de una serie de editores que se especializan en el suministro de manuales de información técnica a talleres de reparación independientes. Este manual del usuario puede emplearse como guía para que comience con el procedimiento de resolución de problemas. Su aprendizaje real puede lograrse de mejor modo mediante la experiencia. A medida que se torne más hábil en el uso de este multímetro automotor para la resolución de problemas, muy pronto aprenderá a detectar cómo determinados síntomas eléctricos se relacionan con diversos problemas de capacidad de manejo. Características del medidor • Mediciones precisas de frecuencia y pulso con 20,000 recuentos en la pantalla de alta resolución de 4000 recuentos. • El gráfico de barras analógico de alta velocidad de 41 segmentos se actualiza 20 veces/s, lo que ofrece una precisión casi perfecta en tiempo real. • Prueba precisa de circuitos electrónicos automotores y mediciones avanzadas expresadas en voltios de CC/CA, amperios de CC/CA, resistencia, etc. • Lectura directa de la permanencia sin usar la tabla de conversión del ciclo de trabajo a la permanencia al probar la inyección electrónica de combustible, los carburadores de retroalimentación y los sistemas de encendido • Medición de RPM para motores de automóviles con 1 a 12 cilindros, usando los cables de prueba o el captador inductivo • Función de ms-ancho de pulso para la prueba de inyectores de combustible en tipos de PFI (Inyector de combustible en puerto) y TBI (Inyector de cuerpo del acelerador) • Para mediciones precisas de RPM, permanencia, ciclo de trabajo y ms-ancho de pulso de los inyectores, el medidor dispone de siete activaciones +/- de siete pasos regulables en 1 a 12 cilindros, de 2 o 4 tiempos para motores fuera de borda, motocicletas y motores convencionales • Medición de temperatura de hasta 2,498 °F (1,370 °C) para catalizadores, interruptor de ventilador, etc. • Medición de capacitancia y frecuencia no automotriz • Pantalla con retroiluminación • Comunicación mediante USB

y la colocación automática del punto decimal. Cuando el medidor está activado, todos los segmentos y símbolos de la pantalla aparecen brevemente durante una prueba automática.

El gráfico de barras analógico ofrece una representación analógica de las lecturas y se actualiza 20 veces por segundo. El gráfico de barras de 2 × 41 segmentos se ilumina de izquierda a derecha a medida que aumenta la entrada. El gráfico de barras es más fácil de leer cuando los datos generan que la pantalla digital cambie rápidamente. También es útil para establecer tendencias o datos direccionales. Las barras también indican el nivel de activación. 3. Botón “±TRIG” (Activación ±) Este botón “± TRIG” (Activación ±) puede utilizarse para alternar entre la pendiente de activación negativa (-) y positiva (+) y regular el nivel de activación. Cuando el medidor está en la función de medición de RPM, ciclo de trabajo, ancho de pulso, frecuencia (Hz automotriz) o de permanencia, mantenga presionado el botón “± TRIG” (Activación ±) durante 1 segundo para alternar entre la pendiente de activación negativa (-) y positiva (+). La pendiente está indicada por el signo + o - al lado de “TRIG” (Activación ±) en la esquina inferior izquierda de la pantalla. El medidor elige por configuración predeterminada la pendiente de activación negativa (-). Una vez que la pendiente de activación esté seleccionada, presione el botón “± TRIG” (Activación ±) repetidamente para ajustar el nivel de activación si la lectura del medidor es demasiado alta o inestable. El ajuste del nivel de activación tiene siete pasos. Presione el botón “± TRIG” (Activación ±) para moverse un paso a la vez para seleccionar un nivel de activación adecuado. PASO DE ACTIVACIÓN Nivel de tensión (RPM, ciclo de trabajo, ms, Hz [automotriz], permanencia) Nivel de activación aproximado tal como lo indica el gráfico de barras +4 +8.2 V +3 +6.8 V +2 +3.2 V +1 +1.4 V -1 -1.4 V -2 -3.2 V -3 -6.8 V

Se utiliza para ingresar o salir del modo Relativo así como para activar o desactivar la función de comunicación mediante USB. Presione este botón “REL” para ingresar en modo Relativo. El medidor almacena la lectura actual como referencia para las mediciones posteriores. Aparece “ ” como un indicador del modo Relativo, y la pantalla indica cero. En modo Relativo, cuando realice una nueva medición, la pantalla muestra la diferencia entre la referencia y la medición nueva. Para salir del modo Relativo, simplemente presione el botón “REL” (Relativo) nuevamente. “ ” desaparece. Nota: • El medidor ingresa en el modo de rango manual cuando entra en el modo Relativo. • Cuando se utiliza el modo Relativo, el valor real del objeto bajo prueba no debe exceder la lectura de rango completo del rango seleccionado. Use un rango de medición más alto, si es necesario. • El modo Relativo no está disponible en las funciones de prueba de diodos y de continuidad. Mantenga presionado este botón “REL” (Relativo) durante 1 segundo para activar la función de comunicación mediante USB, aparecerá “ ” en la pantalla como una indicación. Para desactivar la función de comunicación mediante USB, mantenga presionado este botón “REL” (Relativo) durante 1 segundo nuevamente. “ ” desaparece. 5. Botón “DWL” (Permanencia) Este botón “DWL” (Permanencia) se puede utilizar para seleccionar la función de medición de permanencia o alternar entre las funciones de prueba de resistencia y continuidad. Cuando el medidor está en la función RPM IG, puede presionar el botón “DWL” (Permanencia) para seleccionar el modo de medición de permanencia; aparecerá “DWL” (Permanencia) en la pantalla como una indicación. La permanencia es el número de grados de rotación del distribuidor donde los puntos permanecen cerrados. La permanencia se puede medir para 1 a 12 cilindros. La conversión entre el ciclo de trabajo y la permanencia puede obtenerse mediante la siguiente fórmula: % de ciclo de trabajo = Permanencia (en grados) × Cant. de cilindros × 100 % 360 grados Permanencia = 360 grados × % de ciclo de trabajo Cantidad de cilindros 100 % Cuando el medidor está en la función de permanencia, puede presionar el botón “DWL” (Permanencia) nuevamente o el “% DUTY” (% de trabajo) para volver a la función en la cual estaba el medidor justo antes de ingresar en la función de permanencia. Cuando el interruptor giratorio esté en la posición “Ω ”, presione el botón “DWL” (Permanencia) para cambiar entre las funciones de prueba de resistencia y continuidad. Se puede utilizar una prueba de continuidad para verificar que existe un circuito cerrado. La función de continuidad detecta cortocircuitos y circuitos abiertos que duran tan solo 100 milisegundos. En el rango de 400 Ω, la resistencia de menos de 40 Ω genera que suene la alarma sonora incorporada. Esta puede ser una valiosa ayuda para la resolución de problemas cuando se buscan fallas intermitentes asociadas con conexiones, cables, relés, interruptores, etc.

Se usa para conmutar entre la función de CC y CA o entre °C y °F. Cuando el interruptor giratorio se encuentra en la posición “ ”, “10 ”, “m ” o “µ ”, puede presionar este botón “DC/AC” (CC/CA) para cambiar entre la función de CA y CC; cuando la función CA está activada, aparecerá “ ” en la pantalla como una indicación; cuando está activada la función CC, aparecerá “ ” en la pantalla. Presione el botón “DC/AC” (CC/CA) para cambiar entre °C y °F cuando el interruptor giratorio esté en la posición “TEMP” (Temperatura). Cuando se selecciona la medición de temperatura en grados Celsius, aparecerá “°C” en la pantalla como una indicación; y cuando se selecciona la medición de temperatura en grados Fahrenheit, aparecerá “°F” en la pantalla como una indicación. 7. Interruptor giratorio Las siguientes funciones se seleccionan mediante la configuración del interruptor giratorio en una posición correspondiente: Posición del interruptor Función Voltios de CC/CA m Milivoltios de CC solamente Ω Prueba de resistencia/continuidad (ohmios) Prueba de diodos Capacitancia (Microfaradios) TEMP Temperatura (Fahrenheit y Celsius) Medición de frecuencia (frecuencia no automotriz) (Hercios) Medición de RPM en motores de 2 o 4 tiempos con el captador inductivo en un cable de la bujía. Medición de RPM en motores de 1 a 12 cilindros con los cables de prueba en el lado principal de la bobina de encendido y medición de ciclo de trabajo, ancho de pulso, Hz (automotriz) y permanencia. 10 Corriente (Amperios) CC/CA m Corriente (Miliamperios) CC/CA µ Corriente (Microamperios) CC/CA OFF Apaga el medidor 8. Terminal “ ” Terminal de entrada para las mediciones de tensión, resistencia, continuidad, RPM, diodos, frecuencia, capacitancia, temperatura, ciclo de trabajo, ancho de pulso y permanencia.

Terminal común (retorno) para todas las mediciones. 10. Terminal “mA μA” Terminal de entrada para mediciones de corriente < 400 mA. 11. Terminal “A” Terminal de entrada para mediciones de corriente entre 400 mA y 10 A. 12. Botón “RANGE” (Rango) Este botón “RANGE” (Rango) puede utilizarse para: • Alternar entre el modo manual y el modo de rango automático así como para seleccionar el rango manual deseado. • Seleccione el número de cilindros (1, 2, 3, 4, 5, 6, 8, 10 o 12) que se corresponda con el motor cuando el medidor está en función de permanencia o RPM IG. • Alternar entre motor de 2 tiempos (o motor de 4 tiempos con sistema de encendido sin distribuidor) y motor de 4 tiempos cuando el medidor está en la función RPM IP. En una función que tiene el modo de rango manual y el modo de rango automático, el medidor elige de forma predeterminada el modo de rango automático y aparece “ ” en la pantalla como una indicación. Presione el botón “RANGE” (Rango) para ingresar al modo de rango manual, desaparecerá “ ” y el medidor permanecerá en el rango actual. En el modo de rango manual, puede presionar el botón “RANGE” (Rango) para seleccionar el rango más elevado siguiente. En el rango más alto, el medidor se ajusta al rango más bajo. Para salir de modo manual y volver al modo de rango automático, mantenga presionado el botón de “RANGE” (Rango) durante 1 segundo; aparecerá “ ” en la pantalla como una indicación. Seleccione siempre un rango superior al que espera que se encuentre la corriente o tensión. Luego, seleccione un rango inferior si necesita una mayor precisión. Si el rango es demasiado alto, las lecturas son menos precisas. Si el rango es demasiado bajo, el medidor muestra “OFL” (Sobrecarga) como una indicación de sobrecarga. Cuando el medidor está en la función de RPM IG o de permanencia, presione el botón “RANGE” (Rango) para alternar entre 1, 2, 3, 4, 5, 6, 8, 10 o 12 cilindros. El número de cilindros seleccionado se indica mediante el número que precede al texto CYL (Ciclo) en la pantalla. Cuando el medidor está en la función RPM IP, presione el botón “RANGE” (Rango) para alternar entre motor de 2 tiempos (o motor de 4 tiempos con sistema de encendido sin distribuidor) y motor de 4 tiempos; el número seleccionado de tiempos (o carreras) lo indica el símbolo (“ ” o “ ”). 13. Botón “% DUTY” (% de trabajo) Cuando el medidor está en la función RPM IG, presione este botón “% DUTY” (% de trabajo) para medir el ciclo de trabajo (o factor de trabajo) en porcentaje; aparece una lectura en %. Ciclo de trabajo es el porcentaje del tiempo en el cual una señal está por encima o por debajo del nivel de activación durante un ciclo.

aparece una lectura en ms. El ancho de pulso es el tiempo durante el cual un actuador está activado. Por ejemplo, los inyectores de combustible se activan mediante un pulso electrónico desde el módulo de control del motor. Este pulso genera un campo magnético que hace que se abra la válvula de la boquilla del inyector. El pulso finaliza y la boquilla del inyector se cierra. Este tiempo de abierto a cerrado es el ancho de pulso y se mide en milisegundos (ms) Para seleccionar la función de frecuencia, presione el botón “% DUTY” (% de trabajo) de nuevo; aparece una lectura en Hz. La frecuencia es la cantidad de ciclos que una señal completa cada segundo. Puede pasar a través de RPM, ciclo de trabajo, ancho de pulso y frecuencia presionando este botón “% DUTY” (% de trabajo). Cuando el interruptor giratorio se encuentre en la posición “RPM IG”, puede presionar el botón “DWL” (Permanencia) para seleccionar la función de medición de permanencia; aparecerá “DWL” (Permanencia) en la pantalla como una indicación de dicha función. Cuando se encuentre en la función de medición de permanencia, puede presionar el botón “DWL” (Permanencia) nuevamente o “% DUTY” (% de trabajo) para regresar a la función anterior desde la cual el medidor ingresó en la función de medición de permanencia. 14. Botón “HOLD” (Bloqueo) Se utiliza para ingresar o salir del modo de Bloqueo así como para encender o apagar la retroiluminación. Presione este botón “HOLD” (Bloqueo) para ingresar al modo de Bloqueo. Aparece “ ” en la pantalla como una indicación y el medidor retiene la lectura actual en la pantalla. En el modo de Bloqueo, cuando el medidor detecta una lectura estable nueva, emite una alarma sonora y muestra la nueva lectura estable. Para salir del modo de Bloqueo, presione el botón “HOLD” (Bloqueo) nuevamente. “ ” desaparece. Nota: Cuando el medidor está en el modo de Registro o Relativo, la función de Bloqueo simplemente congela la lectura actual no actualizará la pantalla con la nueva lectura estable. Para encender o apagar la retroiluminación, mantenga presionado este botón “HOLD” (Bloqueo) durante 1 segundo. 15. Botón “REC” (Registro) Presione el botón “REC” (Registro) para ingresar el modo de Registro, aparecerá “ ” en la pantalla como una indicación. (El medidor saldrá del modo rango automático y permanecerá en el rango actual cuando ingresa en modo de Registro). Esta función le permite registrar como el valor máximo, mínimo y promedio de una serie de mediciones en la misma función y rango. Esta medidor emite una alarma sonora cada vez que se registra un valor máximo o mínimo nuevo. Presione el botón “REC” (Registro) para desplazarse a través de los valores máximo, mínimo y promedio. Cuando se captura una sobrecarga, se emite una alarma sonora y el medidor muestra “OFL” como una indicación de sobrecarga. El medidor solo puede registrar durante 24 horas en este modo. Nota: El modo de Registro no está disponible en la función de diodos y continuidad. 16. Puerto USB

opera durante 30 minutos (1 hora en el modo de Registro) mientras que la tensión de entrada sea inferior a 1 V. Cuando el interruptor giratorio se encuentre en otra posición, el medidor se apagará automáticamente si no lo opera durante 30 minutos (1 hora en el modo de Registro). Aproximadamente 30 segundos antes de que el medidor se apague automáticamente, el símbolo “ ” se encenderá parpadeando para recordarle que el medidor se apagará. Para encender el medidor nuevamente, coloque el interruptor giratorio en la posición OFF (Apagado) primero y, luego, en la posición deseada. Para desactivar la función de apagado automático, encienda el medidor mientras mantiene presionado el botón “HOLD” (Bloqueo). Con el captador inductivo El medidor se comercializa con un captador inductivo. El captador inductivo toma el campo magnético generado por la corriente en el cable de la bujía y lo convierte en un pulso que activa la medición de RPM por parte del medidor. 4. COMPRENSIÓN DE LA PANTALLA 2 1 5 6 9 8 7 13 12 11 10 14 15 16 17 18 19 20 22 23 24 25 26 3 4 21

revoluciones por minuto en motores de 1 a 12 cilindros usando los cables de prueba en el lado principal de la bobina de encendido. 2. . Aparece cuando se ha seleccionado el modo RPM IP. En este modo, se pueden medir las revoluciones por minuto en motores de 2 o 4 tiempos con el captador inductivo en un cable de la bujía. 3. . Aparece cuando se selecciona el modo de permanencia. 4. . Aparece cuando se selecciona el modo de ciclo de trabajo. 5. 18 . Aparece cuando un determinado número de cilindros se selecciona en el modo de permanencia o RPM IG. Presione el botón “RANGE” (Rango) para alternar entre motores de 1, 2, 3, 4, 5, 6, 8, 10 o 12 cilindros. 6. . Aparece cuando se ha seleccionado 4 tiempos en el modo RPM IP. Presione el botón “RANGE” (Rango) para alternar entre motores de 2 y 4 tiempos. 7. . Aparece cuando se ha seleccionado 2 tiempos en el modo RPM IP. Presione el botón “RANGE” (Rango) para alternar entre motores de 2 y 4 tiempos. 8. . Indica que el valor que se muestra es el promedio de todas las lecturas realizadas desde que se ingresó en el modo de Registro. 9. . Aparece cuando se selecciona la prueba de diodos. 10. . Aparece cuando se activa el modo Relativo. 11. . Aparece cuando se activa el modo de Registro. 12. . Aparece cuando se selecciona la prueba de continuidad. 13. . Aparece cuando el modo de Bloqueo está activo. 14. . Aparece cuando el nivel de la batería es bajo. ADVERTENCIA PARA EVITAR FALSAS LECTURAS, QUE PODRÍAN PRODUCIR DESCARGAS ELÉCTRICAS O LESIONES PERSONALES, REEMPLACE LA BATERÍA EN CUANTO APAREZCA ESTE INDICADOR DE BATERÍA BAJA. 15. . Indica que el valor que se muestra es la lectura máxima realizada desde que se ingresó en el modo de Registro. 16. . Aparece cuando se activa el modo de rango automático. 17. . Indica que el valor que se muestra es la lectura mínima realizada desde que se ingresó en el modo de Registro. 18. . Aparece cuando se selecciona la función de medición de CC. 19. . Aparece cuando se selecciona la función de medición de CA. 20. . Indica lecturas negativas. En modo Relativo, este signo indica que la entrada actual es inferior a la referencia almacenada. 21. . Indica que la función de apagado automático se ha activado. 22. . Indica que se ha activado la función de comunicación mediante USB. 23. . Aparece cuando se selecciona una pendiente de activación - o + mientras el medidor se encuentra en el modo RPM IP o RPM IG (ciclo de trabajo, ancho de pulso, permanencia o Hz). El medidor elige por configuración predeterminada una pendiente de activación - (negativa). Presione el botón “± TRIG” (Activación ±) durante 1 segundo para cambiar entre la pendiente de activación positiva (+) y negativa (-). También aparece cuando el gráfico de barras indica el nivel de activación.

También indica una pendiente de activación - (negativa) o + (positiva) cuando se ha seleccionado una pendiente. TIEMPO ALTO TIEMPO BAJO 1 CICLO DE TRABAJO Seleccione una pendiente de activación negativa (-) para medir el tiempo bajo (-) y una pendiente de activación positiva (+) para medir el tiempo alto (+). Por ejemplo, cuando se realiza la medición del ciclo de trabajo del solenoide de control de mezcla, el tiempo (-) bajo es el tiempo de encendido, en la mayoría de los casos. 25. ESCALA DE VISUALIZACIÓN ANALÓGICA. Se muestra con indicadores analógicos de 41 posiciones. 26. Los siguientes símbolos indican la unidad de valor visualizado: DWL° El número de grados de rotación del distribuidor donde los puntos permanecerán cerrados, medido para 1 a 12 cilindros % Porcentaje, se utiliza para la medición del ciclo de trabajo °C/°F Medición de la temperatura en grados Fahrenheit o centígrados Ω Ohmios kΩ Kiloohmio (1 × 10 ohmios) Megaohmio (1 × 10 ohmios) Hercios (1 ciclo/s) Kilohercio (1 × 10 ciclos/s) Voltios Milivoltios (1 × 10 voltios) Amperios (A) Miliamperios (1 × 10 A) Microamperios (1 × 10 A) Microfaradios (1 × 10 faradios) Milisegundos (1 × 10 segundos) 6 3 -3 -3 -6 -6 -3 3 MΩ Hz kHz V mV A mA µA µF ms

Una de las herramientas de diagnóstico eléctrico más común es un multímetro digital (digital multimeter, DMM). Un DMM es simplemente un patrón electrónico para realizar mediciones eléctricas. Los DMM tienen muchas funciones y características especiales, pero el uso más común es para medir tensión, corriente y resistencia. Un multímetro automotor como este multímetro también puede medir frecuencia, RPM, ciclo de trabajo, permanencia, ancho de pulso, temperatura, capacitancia e, incluso, el estado de los diodos. Consideraciones generales para realizar mediciones • Precisión Un rango de medición determina el valor máximo que el medidor puede medir. La mayoría de las funciones del medidor tiene más de un rango. Al realizar una medición, es muy importante que se encuentre en el rango de medición correcto. La selección de un rango inferior mueve el punto decimal un lugar a la izquierda y aumenta la precisión de la lectura. Cuando la pantalla LCD muestra OFL (sobrecarga), el rango es demasiado bajo; seleccione el rango superior siguiente. • Gráfico de barras analógico El gráfico de barras es útil para establecer tendencias o datos direccionales. Es más fácil de leer cuando los datos generan que la pantalla digital cambie rápidamente. • Cortador de seguridad Al medir tensión, asegúrese de que el cable de prueba de color rojo esté conectado al conector de entrada “ ”; si el cable de prueba de color rojo está conectado al conector “A” o “mA μA”, puede ser objeto de lesiones o puede dañar el medidor. Al medir corriente, no conecte el cable de prueba de color rojo al conector de entrada “ ”. Los cortadores de seguridad del medidor se utilizan para evitar la conexión al terminal de entrada incorrecto. Mediciones de tensión Las mediciones de tensión son pruebas dinámicas que miden la tensión en un circuito o componente con la alimentación encendida. Las mediciones de tensión se llevan a cabo con los cables de prueba conectados entre los elementos del circuito bajo prueba. ADVERTENCIA PARA EVITAR DESCARGAS ELÉCTRICAS Y DAÑO AL INSTRUMENTO, LA TENSIÓN DE ENTRADA NO DEBE EXCEDER 1000 V CC O 750 V CA RMS. NO INTENTE MEDIR UNA TENSIÓN DESCONOCIDA QUE PUEDA EXCEDER 1000 V CC O 750 V CA RMS. NOTA: Al realizar la medición de tensión, este medidor se debe conectar en paralelo con el circuito o elemento del circuito bajo prueba.

Batería de 12 V Configuración del medidor para medir la tensión: • Coloque el interruptor giratorio en la configuración de tensión ( o m ). (La configuración m solamente es para mediciones de milivoltios de CC). • Presione el botón “DC/AC” (CC/CA) para seleccionar la medición de tensión de CA o CC; la pantalla mostrará el símbolo correspondiente. • Inserte el cable de color negro en el conector “COM”. • Inserte el cable de color rojo en el conector “ ”. Conecte: La sonda de color negro al circuito negativo (-) o puesta a tierra. La sonda de color rojo al circuito que viene desde la fuente de alimentación. Mediciones de resistencia La resistencia es una medición estática que significa que debe medirse con la alimentación apagada. Se mide en ohmios (Ω) y los valores pueden variar en gran medida desde unos pocos miliohmios (mΩ) para la resistencia de un contacto a miles de millones de ohmios para aislantes. ADVERTENCIA APAGUE LA ALIMENTACIÓN Y DESCARGUE TODOS LOS CONDENSADORES DEL CIRCUITO A PROBAR ANTES DE REALIZAR MEDICIONES DE LA RESISTENCIA EN EL CIRCUITO. LA MEDICIÓN PRECISA NO ES POSIBLE SI HAY TENSIÓN RESIDUAL O EXTERNA. NOTA: La resistencia en las sondas de prueba puede afectar la precisión en el rango de 400. Realice el cortocircuito de las sondas juntas y presione el botón “REL” (Relativo) para restar la resistencia del cable de prueba de la medición.