Conditions For Clearing MIL/DTC

WARNING: This page is about a different car, the 2003 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.

The PCM turns OFF the MIL after 3 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.