Stored fault codes may be erased from memory at any time by removing power from the PCM for at least 30 seconds. It may be necessary to clear stored codes during diagnosis to check for any recurrence during a test drive, but the stored codes must be written down when retrieved. The codes may still be required for subsequent troubleshooting. Whenever a repair is complete, the stored codes must be erased and the vehicle test driven to confirm correct operation and repair.
Depending on the electrical distribution of the particular vehicle, power to the PCM may be disconnected by removing the PCM fuse in the fusebox, disconnecting the in-line fuse holder near the positive battery terminal or disconnecting the PCM power lead at the battery terminal. Disconnecting the negative battery cable to clear codes is not recommended as this will also clear other memory data in the vehicle such as radio presets.