GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC P2544: Transmission Torque Request Circuit

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 ignition 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.

Conditions for Running the DTC

    • The ignition is ON for greater than 3 seconds.
    • The ignition voltage is 10-18 volts.
    • The serial data circuit initialized.
    • The DTCs run continuously once the above condition is met.

Conditions for Setting the DTC

The ECM detects an invalid signal from the TCM for greater than 4 seconds.

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

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Observe the Freeze Frame/Failure Records with a scan tool.
  2. Clear the DTCs with a scan tool.
  3. Ignition OFF for 30 seconds.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
  5. If DTC P2544 failed this ignition, replace the TCM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

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