AF23-5 Automatic Transaxle

AF23-5 AUTOMATIC TRANSAXLE

DTC P1779

Test 1-7:

Circuit Description with AF23-5 Automatic Transaxle
Engine torque information is sent to the transmission control module (TCM) by the engine control module (ECM) through a communication network called the controller area network (CAN). Two circuits are used to communicate CAN data between the ECM and TCM. A fault in the CAN will not cause DTC P1779 to set by itself. If a CAN fault occurs, other DTCs will set before DTC P1779.

When the ECM sends the TCM a driver requested torque signal that is invalid, DTC P1779 will set. DTC P1779 is a type A DTC.

Conditions for Running the DTC
^ No CAN DTC U2105.
^ The ignition voltage is 8-18 volts.
^ The ignition has been ON for at least 3.0 seconds.
^ Trans. Protection Mode is OFF.
^ The engine is running.

Conditions for Setting the DTC
Engine torque signal is below the lower limit, above the upper limit, or is an unreliable value for 4 seconds.

Action Taken When the DTC Sets
^ The TCM requests the ECM to illuminate the malfunction indicator lamp (MIL).
^ The TCM uses 300 Nm (221 ft. lbs.) as a default value for driver requested torque.
^ The ECM records the operating conditions when the Conditions for Setting the DTC are met. The ECM stores this information as a Freeze Frame.
^ 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 P1779 in TCM history.

Conditions for Clearing the MIL/DTC
^ The ECM turns OFF the MIL after the third consecutive drive trip in which the TCM does not send a MIL illumination request.
^ A scan tool can clear the MIL/DTC.
^ The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
^ The TCM cancels the DTC default actions when the ignition is OFF long enough in order to power down the TCM.