Aisin 81-40LE - Automatic Transmission (Non European Emissions)

DTC P1791 (Non European Emissions)

Conditions for Setting the DTC

* Transmission control module (TCM) detects that malfunction of throttle position signal for 2 seconds continuously

* No DTC U2105

Action Taken When the DTC Sets

* TCM will request the illumination of the hold lamp and store the DTC when the TCM detects a failure on the 1st ignition cycle

* TCM judges the throttle opening is 0 percent for shift point control

* 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 hold 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

* ECM

* TCM