Reading Diagnostic Trouble Codes

Fig. 122 Connecting Service Wire:

EXTRACTING DIAGNOSTIC CODES (CALIFORNIA MODELS)

1. Confirm initial conditions:

a. Battery voltage is at least 11 volts.
b. Throttle valve is fully closed.
c. Transmission is in neutral.
d. All accessories turned OFF.

2. Turn ignition switch ON, but DO NOT start engine.
3. Connect a service wire across terminals T and E1 of the engine check connector. Fig. 122
4. Read the diagnostic code(s) as indicated by the number of flashes of the "CHECK ENGINE" light on the instrument cluster.
5. After codes are extracted, turn-off ignition switch and remove service wire.

Fig. 53 Examples Of Code Intervals:

DIAGNOSIS INDICATION

If no malfunction codes are stored in the ECU, the "CHECK ENGINE" light will flash ON and OFF two times per second repeatedly. In the event of a malfunction, the light will flash every 0.5 second to indicate the first digit of the diagnostic code. This will be followed by a 1.5 second pause and 0.5 second flashes to indicate the second digit of the code. Fig. 53
If there are two or more codes stored in memory, there will be a 2.5 second pause between each code. After all the codes have been displayed, there will be a 4.5 second pause before the codes will be repeated in the same order. This sequence will continue as long as the check connector terminals remain shorted.
In the event that multiple codes are stored, the codes will display in numerical ascending order, with the lowest numbered code displayed first. All codes are retained in the ECU memory, until they are cancelled using the proper procedure.