P2544

DTC P2544

Circuit Description
To improve shift feel, the transmission control module (TCM) may request that the powertrain control module (PCM) reduce engine torque during shift events. When such a request is received, the PCM responds by retarding the base ignition timing and notifying the TCM that the request has succeeded. If the PCM is unable to comply with the request, the PCM sends the TCM a message that the request has failed.

The torque reduction request is sent to the PCM through a communication network called the controller area network (CAN). Two circuits are used to communicate CAN data between the PCM and TCM. A fault in the CAN will not cause DTC P2544 to set by itself. If a CAN fault occurs, other DTCs will set before DTC P2544.

When the TCM receives a torque reduction failure message from the PCM, then DTC P2544 will set. DTC P2544 is a type C DTC.

DTC Descriptor
This diagnostic procedure supports the following DTC:

DTC P2544 Transmission Torque Request Circuit

Conditions for Running the DTC
^ No CAN DTC U0100.
^ The ignition voltage is 10.2 - 15.5 volts.
^ The engine speed is 400 RPM or greater.
^ Trans. Protection Mode is OFF.

Conditions for Setting the DTC
The PCM notifies the TCM that a torque reduction request has failed for 0.080 seconds.

Action Taken When the DTC Sets
^ The TCM increases line pressure.
^ The TCM disables self-learning control.
^ The TCM limits shift lines to 4000 RPM.
^ The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as a Failure Record.
^ The TCM stores DTC P2544 in TCM history.

Conditions for Clearing the MIL/DTC

Step 1 - Step 7:

^ 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.