C12B9

DTC C012C, C121A, C128C, C128F, C12B9, C12BA, C12BB, or C12F7

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (with HP2) (Initial Inspection and Diagnostic Overview)Diagnostic System Check - Vehicle (without HP2) (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.

DTC Descriptors
DTC C121A
- Regenerative Axle Pressure Sensor

DTC C12F7
- Regenerative Axle Pressure Sensor

DTC C128F
- Regenerative Axle Pressure Sensor

DTC C012C 01
- Regenerative Axle Pressure Sensor Short to Battery

DTC C12BA
- Regenerative Axle Pressure Sensor Short to Battery

DTC C012C 06
- Regenerative Axle Pressure Sensor Short to Ground or Open

DTC C12B9
- Regenerative Axle Pressure Sensor Short to Ground or Open

DTC C012C 11
- Regenerative Axle Pressure Sensor Above Maximum Threshold

DTC C128C
- Regenerative Axle Pressure Sensor Above Maximum Threshold

DTC C012C 0F
- Regenerative Axle Pressure Sensor Erratic

DTC C12BB
- Regenerative Axle Pressure Sensor Erratic

DTC C121A
- Regenerative Axle Pressure Sensor

Circuit/System Description

The electronic brake control module (EBCM) uses input from the regenerative axle pressure sensor for more accurate control during a brake and vehicle stability enhancement system (VSES) event. The regenerative axle pressure sensor is internal to the brake pressure modulator valve (BPMV).

Conditions for Running the DTC

* Ignition ON.
* Ignition voltage is greater than 10 volts.

Conditions for Setting the DTC

C128F, C12F7, C121A, C012C 11 or C128C

Internal sensor failure is detected.

C012C 01 or C12BA

A short to battery is detected on the sensor signal circuit.

C012C 06 or C12B9

A short to ground or open is detected signal circuit.

C012C OF or C12BB

Signal is erratic and changes faster than physically allowed.

Action Taken When the DTC Sets

A DIC message and/or a warning indicator may be displayed.

Conditions for Clearing the DTC

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

Reference Information
Schematic Reference

Antilock Brake System Schematics (Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

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

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

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

Circuit/System Verification

1. Verify that DTC C012C, C121A, C128C, C128F, C12B9, C12BA, C12BB or C12F7 is not set.

• If any of the DTCs are set perform the EBCM, module setup, EBCM Relearn.

2. Replace brake pressure modulator valve (BPMV) assembly. If any of the DTCs resets, replace the EBCM.

Repair Instructions

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

* Brake Pressure Modulator Valve Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for EBCM replacement, setup, and programming