C1279

DTC C1279

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 C1279
- Deceleration Sensor

Circuit/System Description

The electronic brake control module (EBCM) monitors the deceleration of the vehicle for Antilock Brake System (ABS) operation.

Conditions for Running the DTC

Ignition switch is in the ON position.

Conditions for Setting the DTC

The EBCM detects a malfunction in the deceleration sensor.

Action Taken When the DTC Sets

The ABS warning indicator turns ON.

Conditions for Clearing the DTC

The condition responsible for setting the DTC no longer exists and the scan tool Clear DTCs function is used.

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 (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 Verification

1. Verify DTC U0123, U0124, or U0126 are not set?

• If DTC U0123, U0124, or U0126 is set, refer to appropriate DTC.

2. Verify DTC C1212, or C1336 are not set?

• If DTC C1212, or C1336 is set, refer to appropriate DTC.

3. Verify yaw rate sensor is correctly installed.

• If yaw rate sensor is not correctly installed, correct installation of yaw rate sensor and using a scan tool perform yaw rate sensor calibration.

Circuit/System Testing

1. Ignition OFF, disconnect the yaw rate sensor connector.
2. Test for less than 1 ohm between the terminals 1 and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, check for 11-14V between terminal 4 and ground.

• If the voltage is not as specified, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the yaw rate sensor.

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