European and N. American Emissions
DTC P1791 (European and N. American Emissions)
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P1791 Malfunction of Throttle Position Signal
Conditions for Setting the DTC
^ The transmission control module (TCM) detects that malfunction of throttle position signal for 2 seconds continuously.
^ No DTCs U2105, P1705
Action Taken When the DTC Sets
^ The TCM will request the illumination of the MIL lamp and store the DTC when the TCM detects a failure on the 1st ignition cycle.
^ The TCM judges the throttle opening is 0 percent for shift point control.
^ The TCM judges the throttle opening is 100 percent for line pressure control.
^ No lock-up
^ No 4th gear
^ No self-learning control
^ No timing solenoid control for N-D
Conditions for Clearing the DTC
^ The TCM turns off the MIL lamp when no further failures are detected on the next ignition cycles.
^ The scan tool can clear the DTC from the TCM history.
^ The TCM clears the DTC from the TCM history memory after 40 consecutive ignition cycles without fault.
Cause for Failure
^ Wiring harness or connector between engine control module (ECM) and TCM
^ The ECM
^ The TCM
