Clearing Diagnostic Trouble Codes: Self-Erasure
WARNING: This page is about a different car, the 2002 Oldsmobile Aurora. However, it is still accessible from the selected car via links, so may be relevant.
After 3 consecutive ignition cycles that the diagnostic runs and does not fail, PCM will turn off the malfunction indicator light. At that time, the PCM will automatically switch to a warm-up cycle counter. A warm-up cycle occurs when engine temperature increases 22°F from start-up and reaches a minimum of 160°F (71°C). The PCM will clear DTCs from memory after 40 consecutive warm-up cycles if the recent malfunction does not reoccur in that time.