Clearing Diagnostic Trouble Codes

CAUTION: To prevent major damage to the PCM, the key must be in the OFF position any time PCM power is disconnected or reconnected. This applies to not only trouble code clearing, but also when removing a battery cable for component repair or replacement and testing procedures.

PROCEDURE:

To clear the trouble codes from the memory of the PCM, either to determine if the malfunction will occur again or because a repair has been completed, the PCM power feed must be disconnected for at least thirty (30) seconds. Depending on how the vehicle is equipped, the PCM power feed can be disconnected at the positive battery terminal pigtail, the in-line fuse holder that originates at the positive connection at the battery, or the PCM fuse in the fuse block. The negative battery terminal may be disconnected, but other on-board memory data, such as pre-set radio tuning, will also be lost.

When using a hand held diagnostic scanner, or SCAN tool to read codes, clearing the diagnostic trouble codes is done in the same manner as in the above procedure.


After the computer memory has been cleared, a change may be noted in vehicle performance. To restore normal vehicle performance, drive with engine at normal operating temperature, with the accelerator pedal going through idle, part throttle, and moderate acceleration modes until normal performance is restored.