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

DTC P1781 (Non European Emissions)

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P1781 Engine Torque Signal

Conditions for Setting the DTC

* Transmission control module (TCM) detects that malfunction of engine speed signal for 2 seconds
* 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
* No engine torque reduction control
* No lock-up
* No engagement pressure control
* No 4th gear
* No self-learning control
* No timing solenoid control for N-D
* TCM judges the engine revolution is 0 RPM

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 of Failure

* Wiring harness or connector between engine control module (ECM) and TCM
* ECM
* TCM