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®
CP9087
TM
PROFESSIONAL
IGNITION MODULE &
TEST
ENGINE SENSOR TESTER
HIGH
LOW
POWER OFF
RICH
RANGE Select
LOW,
VOLTS
LEAN
VOLTS
OHMS
FREQUENCY
FUNCTION
PULSE
SIGNAL COMMON TRIGGER POWER 9V
9V BATTERY TEST: 1) SET RANGE TO HIGH.
2) SET FUNCTION TO OHMS. 3) DISCONNECT ALL LEADS.
O.K. IF TOPMOST TEST LIGHT IS ON. WEAK IF ANOTHER LIGHT IS ON.
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Vehicle Service Info The following publishers have manuals containing diagnostic information for electronic engine control and ignition systems. Contact the publishers for availability and pricing, specifying the make, model and year of your vehicle. Some manuals may be available at auto parts stores or your local public library. Vehicle Service Manuals Chilton Book Company Haynes Publications Chilton Way 861 Lawrence Drive Radnor, PA 19089 Newbury Park, CA 91320 Cordura Publications Motor’s Au
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Index Vehicle Service Information ...................... Inside front cover Section Safety Precautions ............................................................... ii Tester Basics ............................................. 1-1 1 Testing Sensors .......................................... 2-1 2 • Troubleshooting Tips .......................................... 2-1 • Engine Coolant Temperature .............................. 2-2 • Inlet Air Temperature .........................................
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Safety First General Safety Guidelines to Follow When Working on Vehicles • Always wear approved eye protection • Always operate the vehicle in a well-ventilated area. Do not inhale exhaust gases – they are very poisonous! • Always keep yourself, tools, and test equipment away from all moving or hot engine parts. • Always make sure the vehicle is in Park (automatic transmission) or Neutral (manual transmission) and that the parking brake is firmly set. Block the drive wheels. • Never lay tools
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Section Tester 1 Basics — Description of Controls and Accessories — Installing and Checking the 9 Volt Battery Note: Detailed procedures for testing sensors and ignition modules are located in Section 2 (sensors) and Section 3 (ignition modules). Controls power to the Tester and selects measure- 1 ment range sensitivity (as required by various RANGE sensor tests). Switch • POWER OFF - No power supplied to either the tester or RED test lead. • LOW - Tester powered up for use. Voltage from 9 volt
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Section 1 A single TEST light turns on to show the level of a measured signal 3 (voltage, resistance or frequency). When signal values are low, the TEST light is off or near the bottom of the column. The TEST light TEST moves higher up the column as the signal level increases. Lights Sensor tests involve working the sensor and watching the TEST light move up, down or flash. Note that the motion of the light is more important than its actual position. Used when testing ignition modules. The PULSE
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Tester Basics 6 IGNITION MODULE &
IGNITION MODULE &
TEST ENGINE SENSOR TESTER ENGINE SENSOR TESTER 3 HIGH
LOW
1 POWER OFF RICH RANGE 5 Select
LOW,
VOLTS LEAN VOLTS
OHMS
2 FREQUENCY FUNCTION PULSE 4 7 SIGNAL COMMON TRIGGER POWER 9V 9V BATTERY TEST: 1) SET RANGE TO HIGH.
2) SET FUNCTION TO OHMS. 3) DISCONNECT ALL LEADS.
O.K. IF TOPMOST TEST LIGHT IS ON. WEAK IF ANOTHER LIGHT IS ON. 8 9 Allows test lead to probe sensor circuits when the sensor is 7 connected to vehicle wiring harness.
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9V Section 1 Tester Basics 8 Used when checking some ignition modules. Makes extra connections as required for testing. Jumper Lead Used for easier attachment of test leads to certain 9 sensor or wiring connector pins. Connector • Push one end of the adapter onto the desired Pin Adapters connector pin. • Grasp the other end with the test lead clip. A 9-volt transistor radio battery must be installed to Sensor power the unit. Use an alkaline battery (conventional Tester batteries are too weak for
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6DLC24 Section 2 Section 2 Testing Sensors Save yourself time! Always begin with a thorough Troubleshooting visual and “hands-on” inspection. You can often Tips find the cause of many problems by just looking. • Has the vehicle been serviced recently? Sometimes things get reconnected in the wrong place, or not at all. • Don’t take shortcuts. Inspect hoses and wiring which may be difficult to see due to location. • Inspect the air cleaner and ductwork for defects. • Check sensors and actuators fo
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Section 2 Engine TEMPERATURE HIGH SENSOR RESISTANCE LOW Cold Hot Typical Engine Coolant TEMPERATURE Temperature Sensor The engine temperature sensor is a thermistor - a What is It? resister whose resistance changes with tempera- ture. The hotter the sensor gets, the lower the resistance becomes. The thermistor is mounted inside the tip of a threaded metal housing. This is a 2-wire sensor. (Exception: some Chrysler engines have a dual sensor with three wires.) The computer needs to know engine t
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Air TEMPERATURE HIGH SENSOR RESISTANCE LOW Cold Hot Typical Air Temperature Sensor TEMPERATURE What is It? The air temperature sensor is a thermistor - a resister whose resistance changes with temperature. The hotter the sensor gets, the lower the resistance becomes. The thermistor is mounted inside the tip of a threaded metal housing. This is a 2-wire sensor. The computer needs to know air temperature to How is It calculate the amount of air entering the engine. Used? Then, the computer can pro
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Section 2 Testing Sensors Temperature Sensor Test Procedure Use this procedure for testing all engine coolant or inlet air temperature sensors. Exceptions: • Certain Toyota, Nissan and Ford engines using vane airflow sensors have the air temperature sensor built into the vane airflow assembly. Refer to page 2-40 for testing. • GM 1988 2.8L Mass Airflow Sensor (5 pin only) also has a built-in air tempera- ture sensor. Use same test procedure as for vane airflow temperature sensor. Refer to page 2
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Engine Air TEMPERATURE 6) Verify test clips make good contact and do not touch each other. HIGH
Make sure red and green test clips are not touching anything. LOW
POWER OFF 7) Set RANGE switch to HIGH. RANGE 8) Set FUNCTION switch to OHMS. VOLTS
OHMS
FREQUENCY 9) Note TEST light position on tester. FUNCTION If the sensor is good, the light will move downwards as the sensor heats up. 10) On-Car test only: Disconnect test leads and reconnect sensor to vehicle wiring harness. 11) Heat sensor ti
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Section 2 Testing Sensors TYPICAL THROTTLE POSITION SENSORS HIGH What Throttle Position Sensor SIGNAL
The throttle position sensor is a VOLTAGE is It? potentiometer - a type of variable resistor (similar to a dashboard dimmer control). These sensors come LOW in a wide variety of styles - some with MIN. MAX. ROTATION connectors at the end of a short wire “pigtail”. The computer supplies power and ground to the sensor. The sensor has an element which is turned (rotary type) or pushed (linear type
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THROTTLE POSITION Sensor/Switch • Sometimes a second switch is used to signal a wide open throttle condition. This switch is normally open (or closed - depends upon vehicle) when the throttle is at idle or just partially open. The switch operates when the throttle is opened beyond a certain point. (The amount of throttle opening required to operate the switch varies with vehicle.) The computer uses throttle position to determine engine How it is operating condition: idle (closed throttle), cruis
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Section 2 Testing Sensors Throttle Position Sensor Connectors = Test A, page 2-10 A Some sensors require more than one test. = Test B, page 2-12 B Note: If the Red and Black test lead hook-ups are reversed, the TEST light will move in the opposite direction during Test A. This does not affect the accuracy of the test or harm the sensor. GM FORD Black Red Yellow Yellow A A Black Red GM, FORD, CHRYSLER, HONDA FORD Black Yellow Red Yellow A A Black Red HONDA HONDA HONDA Yellow A A A Black Red Blac
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THROTTLE POSITION Sensor/Switch TOYOTA TOYOTA/NISSAN A B Red Yellow Black Yellow Black Not used on some B B vehicles. Perform this test only if vehicle Yellow Black Black Yellow mating connector has 3 wires. A Red Yellow Black Yellow Black Black Not used on some Yellow vehicles. Perform this test only if B B vehicle mating connector Some sensors have has 3 wires. cable attached here. Testing is identical. 2-9
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Section 2 Testing Sensors TEST A - Throttle Position Sensor Important: If more than one hook-up is shown, it means more than one test is required to check all parts of the sensor. Do all tests shown for your sensor. The letter next to the hook-up refers to the test procedure. Sensor may be tested on or off vehicle. (Exception: On-car test only for most Honda - sensor permanently attached to throttle body.) Warning: Observe all safety precautions (see page ii) if testing sensor on vehicle. 1) Ve
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THROTTLE POSITION Sensor/Switch 7) Honda only: 1988-92 Civic and CRX – Remove vacuum hose from dashpot diaphragm. – Apply 20 in. Hg to the dashpot diaphragm using a hand vacuum pump. – The dashpot diaphragm is part of the throttle body assembly. It is used to control cold engine fast idle and HIGH
throttle closure speed so engine will not stall. LOW
POWER OFF 8) Set RANGE switch to HIGH. RANGE VOLTS
9) Set FUNCTION switch to VOLTS. OHMS
FREQUENCY 10) Operate sensor - Watch TEST light for re
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Section 2 Testing Sensors TEST B - Throttle Position Switch Important: If more than one hook-up is shown, it means more than one test is required to check all parts of the switch. Do all tests shown for your switch. The letter next to the hook-up refers to the test procedure. Switch may be tested on or off vehicle. Warning: Observe all safety precautions (see page ii) if testing sensor on vehicle. 1) Verify ignition key is OFF. 2) Check Tester battery Refer to page 1-4. Set RANGE switch to POWER
