6L45/6L50/6L80/6L90 - Automatic Transmission

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 Descriptor

DTC P2544

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Transmission Torque Request Signal Message Counter Incorrect

Circuit/System Description

To improve vehicle shift feel, the transmission control module (TCM) is constantly sending the engine control module (ECM) serial data messages with information regarding its request for modifying engine torque. The ECM sets this code when it detects a discrepancy in the structure of this message causing its integrity to be questioned.

An intermittent fault in the controller area network (CAN) circuits will cause DTC P2544 to set.

Conditions for Running the DTC

* The engine run time is greater than 5 seconds.

* No other CAN errors are present.

Conditions for Setting the DTC

* DTC P2544 is a Type B DTC.

* An intermittent fault in the CAN circuits.

Action Taken When the DTC Sets

* DTC P2544 is a Type B DTC.

* The TCM commands maximum line pressure during shifts, which results in very harsh shifts.

Conditions for Clearing the DTC

DTC P2544 is a Type B DTC.

Reference Information

DTC Type Reference

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

Circuit/System Verification

1. DTC P2544 is an informational DTC. Diagnose all other ECM and TCM DTCs prior to DTC P2544. For other DTCs that are set. Refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle.

2. If there are no other ECM and TCM DTCs, diagnosis is accomplished by looking for an intermittent CAN circuit fault. Refer to Scan Tool Does Not Communicate with High Speed GMLAN Device Scan Tool Does Not Communicate with High Speed GMLAN Device.