DTC P2544
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for a
overview of the diagnostic approach.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure
Instructions) provides an overview of each diagnostic category.
DTC Descriptors
DTC P2544
- Transmission Torque Request Circuit
DTC P2544
- Transmission Torque Request Signal Message Counter Incorrect
Circuit/System Description
To improve shift feel, the transmission control module (TCM) is constantly sending the engine control module (ECM) serial data messages with
information regarding it's request for modifying engine speed or torque. The serial data messages are sent through two circuits which are part of a
communication network called the controller area network (CAN). The ECM sets DTC P2544 when it detects a discrepancy in the structure of the
message causing the integrity of the message to be questioned.
An intermittent fault in the CAN circuits will cause the ECM to set DTC P2544.
Conditions for Running the DTC
* The engine run time is greater than 0.5 s.
* No other CAN errors are present.
Conditions for Setting the DTC
The ECM detects that the engine speed and torque modification messages from the TCM are either corrupted or intermittently missing for greater
than 4 s.
Action Taken When the DTC Sets
* DTC P2544 is a Type B DTC.
* The TCM commands maximum line pressure during shifts, which results in harsh shifts.
* The TCM freezes adaptive functions.
Conditions for Clearing the DTC
DTC P2544 is a Type B DTC.
Reference Information
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (See: Diagnostic Trouble Code Descriptions/Powertrain Diagnostic Trouble Code
(DTC) Type Definitions)
Circuit/System Verification
1. DTC P2544 is an informational DTC. Diagnose all other engine control DTCs prior to DTC P2544. Refer to Diagnostic Trouble Code (DTC)
List - Vehicle (See: Diagnostic Trouble Code Descriptions/Diagnostic Trouble Code (DTC) List - Vehicle).
2. If there are no other engine controls DTCs, diagnosis is accomplished by looking for an intermittent CAN circuit fault. Refer to Scan Tool
Does Not Communicate with High Speed GMLAN Device (See: Powertrain Management/Computers and Control Systems/Information
Bus/Testing and Inspection/Symptom Related Diagnostic Procedures/Scan Tool Does Not Communicate with High Speed GMLAN Device).
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
Control Module References (See: Testing and Inspection/Programming and Relearning) for TCM replacement, setup, and programming.
