P2544

DTC P2544

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.

* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC P2544 72

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Transmission Torque Request Circuit Message Counter Incorrect

DTC P2544 74

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Transmission Torque Request Circuit Bus Signal Checksum Error

Circuit/System Description

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

The torque reduction request is sent to the ECM through GMLAN.

Conditions for Running the DTC

* The ignition is ON.

* The DTCs run continuously once the above condition is met.

Conditions for Setting the DTC

The ECM detects an invalid signal from the TCM.

Action Taken When the DTC Sets

DTC P2544 is a Type C DTC.

Conditions for Clearing the DTC

DTC P2544 is a Type C DTC.

Reference Information

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Circuit/System Testing

1. Observe the Freeze Frame/Failure Records with a scan tool.

2. Clear the DTCs with a scan tool.

3. Ignition OFF for 30 s.

4. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

• If any other DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle

• Verify DTC P2544 is not set. If DTC P2544 resets, replace K71 Transmission Control Module.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.

Control Module References Control Module References for TCM replacement, setup, and programming