Conditions for Running the DTC

WARNING: This page is about a different car, the 2010 GMC Sierra and 2010 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.

P0120, P0122, P0123, P0220, P0222, and P0223

DTC P0641 or P0651 are not set.
The run/crank or powertrain relay voltage is greater than 6 V and reduced power is not active.
The ignition is ON or the engine is running.
DTC P0120, P0122, P0123, P0220, P0222, P0223 run continuously when the above conditions are met.

P2135

DTC P0120, P0121, P0122, P0123, P0220, P0222, P0223, P0641, or P0651 are not set.
The run/crank or powertrain relay voltage is greater than 6 V and reduced power is not active.
The ignition is ON or the engine is running.
DTC P2135 runs continuously when the above conditions are met.