Conditions for Running the DTC

WARNING: This page is about a different car, the 2012 GMC Yukon, 2012 Chevrolet Tahoe, and 2012 Cadillac Escalade. However, it is still accessible from the selected car via links, so may be relevant.

P2120, P2122, P2123, P2125, P2127, P2128

DTC P0641 and P0651 are not set.
The ignition is ON or the engine is running.
The run/crank or powertrain relay voltage is greater than 6.0 V and reduced power is not active.
DTC 2120, P2122, P2123, P2125, P2127, P2128 run continuously when the above conditions are met.

P2138

DTC P0641, P0651, P2120, P2122, P2123, P2125, P2127, and P2128 are not set.
The ignition is ON or the engine is running.
The run/crank or powertrain relay voltage is greater than 6.0 V and reduced power is not active.
DTC P2138 runs continuously when the above conditions are met.