Conditions for Running the DTC

WARNING: This page is about a different car, the 2010 GMC Sierra, 2010 GMC Cab & Chassis Sierra, 2010 Chevrolet Silverado, and 2010 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Ignition voltage is between 8.6 volts or greater.
The TCM temperature is between 0°C (32°F) and 170°C (338°F) for 0.25 seconds.
DTC P0634 and has not set this ignition.