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.

Before the ECM can report DTC P2626 failed, DTCs P0101, P0121, P0122, P0123, P0221, P0222, P0223, P0336, and P0338 must run and pass.
The engine is operating.
The ignition 1 voltage is between 10.7-18.0 volts.
The fuel system is in fuel shut-off for more than 5 seconds.
The calculated exhaust temperature is less than 750°C (1,382°F).
The heated oxygen sensors are at operating temperature.
DTC P2626 runs continuously once the above conditions are met.