Conditions For Clearing MIL/DTC

WARNING: This page is about a different car, the 2002 GMC Sierra and 2002 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The PCM turns OFF the MIL after three consecutive ignition cycles in which the diagnostic test runs and passes.
The PCM cancels the DTC default actions when the fault no longer exists and the DTC passes.
The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
A Scan Tool can clear the MIL/DTC.