Self-Diagnostic System: Notes

Powertrain Control Module (PCM) monitors several different circuits of engine control system. If a problem is sensed with a monitored circuit, PCM will store a Diagnostic Trouble Code (DTC) to aid technician in diagnosis of system. If DTC applies to a non-emissions related component or system, and problem is repaired or ceases to exist, DTC will be erased after 40 warm-up cycles.

Certain criteria must be met before a DTC is stored. Criteria may be a specific range of engine RPM, engine temperature, or input voltage to PCM. PCM may not store a DTC for a monitored circuit even if a malfunction occurred. This may happen because certain criteria for the DTC have not been met. Use scan tool connected to Data Link Connector (DLC) to retrieve stored DTCs.