Conditions for Running the DTC

WARNING: This page is about a different car, the 2009 GMC Sierra, 2009 GMC Cab & Chassis Sierra, 2009 Chevrolet Silverado, and 2009 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Ignition voltage is between 8.6-18.0 volts.
The TCM temperature is less than 150°C (302°F) for greater than 5 seconds.
DTC P0634 is not currently active and has not failed in the current key on.