Action Taken When the DTC Sets: P0657

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.

The TCM requests the engine control module (ECM) to illuminate the malfunction indicator lamp (MIL).
While diagnostic response is active, if the shift selector is moved to NEUTRAL, the transmission will shift to NEUTRAL. If the shift selector is moved to REVERSE, the transmission will shift to REVERSE. If the shift selector is moved to a forward range, the transmission will shift to third range.
The TCM inhibits TCC engagement.
DTC P0657 is stored in TCM history.