P1792

AF23-5 AUTOMATIC TRANSAXLE

DTC P1792
Circuit Description with AF23-5 Automatic Transaxle
The engine control module (ECM) sends engine coolant temperature data to the transmission control module (TCM). The TCM uses this data to initiate warm-up shift patterns and to establish default transmission fluid temperature (TFT) values. The data is sent to the TCM 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 P1792 to set by itself. If a CAN fault occurs, other DTCs will set before DTC P1792.
When the TCM receives invalid engine coolant temperature data from the ECM, then DTC P1792 will set. DTC P1792 is a type A DTC.

Conditions for Running the DTC
^ The ignition voltage is 8 - 18 volts.
^ The engine run time is 5 seconds or greater.
^ No CAN DTC U2105.
^ Trans. Protection Mode is OFF.

Conditions for Setting the DTC
The ECM sends no valid engine coolant temperature data to the TCM for 4 seconds.

Action Taken When the DTC Sets
^ The TCM requests the ECM to illuminate the malfunction indicator lamp (MIL).
^ The TCM uses 80°C (176°F) as a default engine coolant temperature value.
^ The ECM records the operating conditions when the Conditions for Setting the DTC are met. The ECM stores this information as Freeze Frame and Failure Records.
^ The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as Failure Record.
^ The TCM stores DTC P1792 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 switch is OFF long enough in order to power down the TCM.