P1791

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