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 DTC clears when the diagnostic runs and does not fail.
A History DTC clears after 40 consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures.
Use a scan tool in order to clear the MIL/DTC.