Conditions for Running the DTC: P2138

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

The system voltage is more than 5.23 volts.
The ignition is in the Unlock/Accessory or Run position.
DTC P0641, P0651, P2120, P2125 are not set.
DTC P2138 runs continuously when the above conditions are met.