Conditions for Running the DTC

WARNING: This page is about a different car, the 2004 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.

The ignition is ON, with the engine OFF or the engine is operating.
The ignition 1 voltage is more than 7 volts.
DTC P0123 runs continuously once the above conditions are met.