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 72: Transmission Torque Request Circuit Alive Counter Incorrect/Not UpdatedDTC P2544 74: Transmission Torque Request Circuit Value Of Signal Protection Calculation Incorrect
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
Circuit/System Testing
- Observe the Freeze Frame/Failure Records with a scan tool.
- Clear the DTCs with a scan tool.
- Ignition OFF for 30 seconds.
- 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 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.
