C128D

DTC C012D, C120A, C128A, C128D, C12BC, C12BD, or C12BE

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 C012D 00
- Brake Boost Regulation Pressure Sensor

DTC C128D
- Brake Boost Regulation Pressure Sensor

DTC C012D 01
- Brake Boost Regulation Pressure Sensor Short to Battery

DTC C12BD
- Brake Boost Regulation Pressure Sensor Short to Battery

DTC C012D 06
- Brake Boost Regulation Pressure Sensor Short to Ground or Open

DTC C12BC
- Brake Boost Regulation Pressure Sensor Short to Ground or Open

DTC C012D 11
- Brake Boost Regulation Pressure Sensor Above Maximum Threshold

DTC C128A
- Brake Boost Regulation Pressure Sensor Above Maximum Threshold

DTC C012D 5A
- Brake Boost Regulation Pressure Sensor Plausibility Failure

DTC C120A
- Brake Boost Regulation Pressure Sensor Plausibility Failure

DTC C012D 0F
- Brake Boost Regulation Pressure Sensor Erratic

DTC C12BE
- Brake Boost Regulation Pressure Sensor Erratic

Circuit/System Description

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

Conditions for Running the DTC

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

Conditions for Setting the DTC

C012D 00, C128D, C012A 11 or C128A

Internal sensor failure is detected.

C012D 01 or C12BD

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

C012D 06 or C12BC

A short to ground or open is detected signal circuit.

C012D 5A or C120A

The boost pressure being commanded is not being achieved.

C012D OF or C12BE

Signal is erratic and changes faster than physically allowed.

Action Taken When the DTC Sets

* The EBCM disables the ABS and vehicle stability enhancement system (VSES) for the duration of the ignition cycle.
* 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

Perform Brake Pedal Travel Measurement and Inspection (Non-Hybrid) (Component Tests and General Diagnostics)Brake Pedal Travel Measurement and Inspection (Two-mode Hybrid) (Component Tests and General Diagnostics).

Circuit/System Testing

1. Verify that DTC C012D, C120A, C128A, C128D, C12BC, C12BD, or C12BE 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