C056E

DTC C056D or C056E

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 C056D 33
- ECU Hardware Performance Special Memory Failure

DTC C056D 34
- ECU Hardware Performance RAM Failure

DTC C056D 35
- ECU Hardware Performance ROM Failure

DTC C056D 36
- ECU Hardware Performance EEPROM Failure

DTC C056D 39
- ECU Hardware Performance Internal Electronic Failure (ECU processor failure)

DTC C056E 41
- ECU Software Performance Operational Software/Calibration Set Not Programmed




Circuit/System Description

This diagnostic applies to internal microprocessor integrity conditions within the Trailer Brake Control Module (TBCM). This diagnostic also addresses if the TBCM is not programmed.


Conditions for Running the DTC

C056D

The Ignition is ON, and DTC C056D runs once an ignition cycle.

C056E

The ignition is ON, with the engine OFF, DTC C056D runs continuously.


Conditions for Setting the DTC

C056D

The TBCM detected a failure in its microprocessor.

C056E

The TBCM is not programmed.


Action Taken When the DTC Sets

* The trailer brake control will be disabled at the end of the current brake apply for the remainder of the ignition cycle.
* The Service Trailer Brake System will be displayed on the Driver Information Center (DIC).



Conditions for Clearing the MIL/DTC

* When the condition for the DTC is no longer present.
* The TBCM automatically clears the history DTC when a current DTC is not detected in 40 consecutive drive cycles.



Reference Information
Schematic Reference

Trailer Brake Control Schematics ([1][2]Electrical Diagrams)
Connector End View Reference

Component Connector End Views
Electrical Information Reference

* Circuit Testing
* Connector Repairs
* Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs

Scan Tool Reference

Control Module References for Scan Tool Information


Circuit/System Verification

Ignition ON, observe the DTC information with a scan tool. DTC C056D and DTC C056E, should not set.

If DTC C056D failed this ignition, replace the TBCM.


If DTC C056E failed this ignition, program the TBCM.



Circuit/System Testing

C056E

Program the TBCM. If DTC C056E sets after programming, perform the following steps:

* If DTC C056D is set, turn off the ignition, wait 30 seconds, turn ignition on, if DTC C056D failed this ignition cycle, replace the TBCM.
* If DTC C056E is set, turn off the ignition, wait 30 seconds, turn ignition on, if DTC C056E failed this ignition cycle, program the TBCM.

• If DTC C056E sets after programming, replace the TBCM.




Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.


Control Module References for TBCM replacement, setup, and programming