Diagnostic Aids

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.

A defective vehicle battery may allow this code to set.
A defective vehicle charging system may allow this code to set.
You may have to drive the vehicle in order to experience a condition.
You need to make certain the engine is not being shut down with a master switch.
In most cases, the TCM is not at fault. Investigate thoroughly prior to replacing the TCM.