Conditions for Running the DTC

WARNING: This page is about a different car, the 2008 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.

The system voltage is more than 7 volts.
The TP sensor 1 voltage is between 0.18-4.63 volts.
DTCs P0121, P0122 and P0123 run continuously when the above conditions are met.