Conditions for Clearing the DTC

WARNING: This page is about a different car, the 2007 Pontiac G5 Pursuit, 2007 Pontiac G5, and 2007 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.

A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
The DTC can be cleared by using a scan tool.
A last test failed, or current DTC, clears when the diagnostic runs and passes.