P2548

DTC P2548

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 P2548
- Vehicle Dynamics System Torque Request Signal Message Counter Incorrect

Circuit/System Description

The electronic brake control module (EBCM) and the engine control module (ECM) simultaneously control the vehicle performance launch. During a performance launch the EBCM sends a serial data message to the ECM requesting torque reduction. If the ECM receives corrupt data from the EBCM, DTC P2548 will set in the ECM. The ECM then sends a serial data message to the EBCM that torque reduction is not allowed.

Conditions for Running the DTC

* The ignition is ON.
* Ignition voltage is greater than 8 V.

Conditions for Setting the DTC

The ECM detects a corrupted data message from the EBCM.

Action Taken When the DTC Sets

* DTC P2548 is a Type B DTC.
* The EBCM disables the TCS for the duration of the ignition cycle.
* The Traction Off indicator turns ON.
* The DIC displays the Service Traction Control message.
* The ABS remains functional.

Conditions for Clearing the DTC

DTC P2548 is a Type B DTC.

Reference Information
Schematic Reference

* Engine Controls Schematics ([1][2]Electrical Diagrams)
* Antilock Brake System Schematics (Electrical Diagrams)

Connector End View Reference

Component Connector End Views (Connector End Views By Name)
Description and Operation

ABS Description and Operation (Description and Operation)
Electrical Information Reference

* Checking Aftermarket Accessories (Checking Aftermarket Accessories)
* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing For Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
* Testing for Electrical Intermittents (Testing For Electrical Intermittents)
* GMLAN Wiring Repairs (GMLAN Wiring Repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Powertrain Diagnostic Trouble Code (DTC) Type Definitions)
Scan Tool Reference

Control Module References (Programming and Relearning) for Scan Tool Information

Circuit/System Verification

1. Verify there are no communication DTCs set.

• If any DTC of this type is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle (Diagnostic Trouble Code (DTC) List - Vehicle).

2. 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.

Circuit/System Testing

Inspect the serial data circuits and connections at the ECM and the EBCM. They should be free from sources of electromagnetic interference and the connections should be clean and tight.

If a condition is found with the serial data circuits or connections, refer to Symptoms - Data Communications (Symptoms - Data Communications).
If no condition is found with the serial data circuits or connections, replace the EBCM.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

Control Module References (Programming and Relearning) for EBCM replacement, setup, and programming