RETRIEVING CODES for vehicles before 96
NOTE: Not all trouble codes will activate MIL (CHECK ENGINE light)
•Before proceeding, make sure the:
◦CHECK ENGINE light circuit is functional. It should be ON when the ignition switch is ON with the engine stopped.
◦Battery voltage is above 11 volts.
◦Throttle valve is fully closed (Throttle Position Sensor IDL points closed).
◦Accessory switches (A/C, etc.) are OFF.
◦Engine is at normal operating temperature (if possible).
•Turn ignition switch to ON position.
◦Do not start the engine.
◦Place a jumper wire across TEl and El terminals in engine check connector.
•Count number of flashes from CHECK ENGINE light.
◦If system is operating normally (with no detected faults), the CHECK ENGINE light will blink continuously
and evenly about 2 times a second.
•Otherwise, the light will blink a number of times equal to the trouble code as follows:
◦The light blinks only (.5 second ON, .5 second OFF) when indicating a number.
◦The light will be OFF for 1.5 seconds between the first digit and the second digit of the code.
◦If more than one code is stored, the light will be OFF for 2.5 seconds before the next code is displayed.
◦Once all code(s) have been displayed, the light will be OFF for 4.5 seconds and then the whole sequence will repeat.
•The diagnostic code series will continue to repeat as long as the check connecter terminals TEl and El are connected.
•When finished, remove the jumper wire.
•After repairing the malfunction, clear the codes from the ECUs memory.
Clearing Trouble Codes
All trouble codes must be purged from the ECUs memory after repairing the faults. Otherwise, code(s) would remain in the ECUs memory indefinitely and would appear along with a new code in the event of a future problem.