Conditions for Clearing the DTC

WARNING: This page is about a different car, the 2003 Pontiac Aztek and 2003 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.

The BCM no longer detects a fault in the signal circuit of the DRL ambient light sensor for more than 1.0 second.
The BCM no longer detects a fault in the low reference circuit of the DRL ambient light sensor for more than 1.0 second.
A history DTC B2647 clears after 100 consecutive ignition cycles.
The BCM receives the Clear Code command from the scan tool.