Action Taken When the DTC Sets

WARNING: This page is about a different car, the 2003 Pontiac Aztek and 2003 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.

The PCM does not illuminate the malfunction indicator lamp (MIL).
The PCM enters PC solenoid valve diagnostic retest mode. The retest mode conducts the following diagnostic routine:

The PCM de-energizes the PC solenoid valve, resulting in maximum line pressure.
After being de-energized for 2 seconds, the PCM commands the PC solenoid valve ON at 0.1 amp for the retest period of 5 seconds.

If no circuit faults are detected during the 5 second retest period, then the PC solenoid valve is returned to normal operation and DTC P0748 diagnostic is passed.
If a circuit fault is detected during the 5 second retest period, then the PCM de-energizes the PC solenoid valve for 2 seconds before reentering the retest mode.

If a circuit fault is detected 5 times in retest mode without returning to normal operation, then the PC solenoid valve is de-energized for the remainder of that ignition cycle.
If a circuit fault is detected 3 times during normal operation, then the PCM de-energizes the PC solenoid valve for the remainder of that ignition cycle.
The PCM freezes transmission adaptive functions.
The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Failure Records.
The PCM stores DTC P0748 in PCM history.