Conditions for Running the DTC

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

DTCs P0606, P1518, P2108 are not set.
The ignition switch is in the crank or the run position.
The ignition voltage is more than 5.23 volts.
The communications between the TAC module and the PCM must be valid.