Antilock Brake System

DTC C056D

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 C056D 00
- Electronic Control Unit Hardware Malfunction

DTC C056D 39
- Electronic Control Unit Hardware Internal Malfunction

DTC C056D 3B
- Electronic Control Unit Hardware Self-Test Malfunction

Circuit/System Description

The internal fault detection is handled inside the control module. No external circuits are involved.

Conditions for Running the DTC

Ignition ON

Conditions for Setting the DTC

In internal hardware failure is detected.

Action Taken When the DTC Sets

* The electronic brake control module (EBCM) disables the ABS, traction control, and stability control for the duration of the ignition cycle.
* The ABS indicator turns ON.
* The traction control/stability control-active indicator turns ON.

Conditions for Clearing the DTC

* A current DTC clears when the diagnostic runs and passes.
* The EBCM will turn OFF the indicators and enable the system functions in the next ignition cycle.

Diagnostic Aids

A newly replaced EBCM can set one or more DTC on its initial ignition ON cycle.

Reference Information
Schematic Reference

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

* 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)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Testing

1. Ignition ON, perform the following calibration procedures. Refer to:

* Steering Angle Sensor Centering (Procedures)
* Vehicle Yaw Sensor Learn (Vehicle Yaw Sensor Learn)
* Brake Pressure Modulator Valve Pressure Sensor Calibration (Testing and Inspection)

2. Verify that DTC C056D is not present.

• If DTC C056D is present, replace the module that set the DTC.

Repair Instructions

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

* Steering Angle Sensor Replacement (Removal and Replacement)
* Vehicle Yaw Sensor with Vehicle Lateral and Longitudinal Accelerometer Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for module replacement, setup and programming