GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2007 🢒 Rainier 🢒 DTC 🢒 DTC P2544

DTC P2544 5.3L and 6.0L

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 Descriptor

DTC P2544: Transmission Torque Request Circuit

Circuit/System Description

The controller area network (CAN) serial data bus is used by the engine control module (ECM) and automatic transmission control module (TCM) to share information. This diagnostic applies to CAN signal failures.

Conditions for Running the DTC
    • No Lost Communications with the ECM, DTC U0100.
    • The engine run time is greater than 5 seconds.
    • No other CAN errors are present.

Conditions for Setting the DTC

P2544

The ECM notifies the TCM that a torque reduction request has failed for 2 seconds.

Action Taken When the DTC Sets

P2544

    • DTC P2544 is a Type B DTC.
    • The TCM commands maximum line pressure.
    • The TCM freezes transmission adaptive functions.

Conditions for Clearing the DTC

DTC P2544 is a Type B DTC.

Reference Information

Schematic Reference

Automatic Transmission Controls Schematics

Connector End View Reference

    •  Automatic Transmission Inline 20-Way Connector End View
    •  Automatic Transmission Internal Connector End Views
    •  Automatic Transmission Related Connector End Views

Description and Operation

Transmission General Information

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

    •  Scan Tool Output Controls
    •  Scan Tool Data List
    •  Scan Tool Data Definitions

Circuit/System Verification
  1. Start the engine; observe the DTC information with a scan tool. CAN DTCs should not set.
  2. Operate the vehicle within the conditions for running the DTC. CAN DTCs should not set.

Circuit/System Testing
  1. Ignition ON, attempt to establish communication with the ECM with a scan tool.
    2. ⇒If no communication with the ECM, refer to Control Module References for further diagnosis.
  2. Ignition OFF, disconnect the harness connector of the ECM.
  3. Ignition ON, verify that 1.5-3.4 volts is available between the CAN serial data low and the CAN serial data high circuits.
    4. ⇒If the voltage is not within the specified range, replace the ECM.
  4. Ignition OFF, test the CAN communication circuits between the ECM and the TCM for an open, short to ground, or a short to voltage.
  5. If the circuits/connections test OK, replace the TCM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for TCM replacement, setup, and programming