Action Taken When the DTC Sets

WARNING: This page is about a different car, the 2003 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

The TCM requests the ECM to illuminate the malfunction indicator lamp (MIL).
The TCM uses the ECM default throttle position value for determining shift speeds.
The TCM turns off the line pressure control solenoid valve (SLT). When the line pressure control solenoid valve is off, line pressure is at maximum and updates to the transmission adaptive pressure (TAP) memory cells are discontinued.
The ECM records the operating conditions when the Conditions for Setting the DTC are met. The ECM stores this information as Freeze Frame and Failure Records.
The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as Failure Records.
The TCM stores DTC P1791 in TCM history.