Conditions for Running the DTC

WARNING: This page is about a different car, the 2007 Hummer H2. However, it is still accessible from the selected car via links, so may be relevant.

DTCs P0068, P0601, P0602, P0604, P0606, P1516, P2108, U0107 are not set.
DTCs P0120 and P0220 are not active at the same time.
The engine is running.
OR
The ignition voltage is more than 8.5 volts with the ignition ON.
The TAC system is not in the battery saver mode.
DTC P2101 runs continuously once the above conditions are met.