Service Information

Volt

DTC C0870 or C12E4

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 C0870 00: Control Module Voltage Reference Output 1 Circuit Malfunction

DTC C12E4 00: ABS Sensor Reference Output Circuit

Circuit/System Description

The electronic brake control module supplies a shared 5 V reference to multiple sensors.

Conditions for Running the DTC

•	Vehicle ON or Vehicle in Service Mode.

•	The ignition voltage is greater than 10 V.

Conditions for Setting the DTC

The electronic brake control module detects an internal 5 V supply failure.

Action Taken When the DTC Sets

•	The ABS indicator turns ON.

•	The red brake indicator turns ON.

•	The traction control/stability control indicator turns ON.

•	The Service Brake Assist and Service StabiliTrak messages are displayed on the driver information centre.

•	The electronic brake control module disables the antilock brake system, the traction control system and the electronic stability program for the duration of the drive cycle.

Conditions for Clearing the DTC

•	The condition for setting the DTC is no longer present.

•	The history DTC will clear after 40 consecutive fault-free drive cycles have occurred.

Reference Information

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

Vehicle in Service Mode.
Verify that DTC C0870 or C12E4 is not set.

⇒	*If either DTC is set*

Replace the K17 electronic brake control module.

⇓	*If either DTC is not set*

All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for electronic brake control module replacement, programming and setup