C0252

DTC C0252

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 C0252 00
- VSES Sensor Uncorrelated

Circuit/System Description

The electronic brake control module (EBCM) controls the vehicle stability enhancement system (VSES) by monitoring the inputs from the yaw rate/lateral accelerometer sensor, wheel speed sensors and steering wheel angle sensor. All of the sensors need to correlate to the vehicle dynamics during the initial drive off in order to enable VSES. Normally this takes place within 100 meters (110 yards).

Conditions for Running the DTC

* Ignition ON.
* Ignition voltage is greater than 10 volts
* The steer angle has been centered.
* The VSES system has not been initialized.
* The direction (understeer or oversteer) of the yaw rate error has not changed.
* The centered lateral acceleration value is less than 0.5 g.
* The yaw rate error is less than 6 degrees/second.
* The side slip error is greater than 1.8 meters per second squared.
* Vehicle is moving.

Conditions for Setting the DTC

* Vehicle is driven greater than 8 km (5 mph) without VSES initialization
* The yaw rate error is greater then 10 degrees/second for 5 seconds, and the yaw has not changed and the lateral acceleration is less than 0.5 g.

Action Taken When the DTC Sets

* The EBCM disables the Antilock Brake System (ABS) /Traction Control System (TCS)/VSES for the duration of the ignition cycle.
* The ABS and VSES indicators illuminate.
* The driver information center (DIC) displays the Service Traction Control and Stabilitrak message.

Conditions for Clearing the DTC

* The condition for the DTC is no longer present or the ignition is cycled.
* The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.

Diagnostic Aids

* The DTC C0252 can be set if the vehicle has been driven above 8 km (5 mph) on a winding road prior to the VSES initialization with the brake pedal applied and while accelerating.
* Driving off with constant steering wheel input or brake switch activation.
* An improperly mounted or loose combination yaw rate/lateral accelerometer sensor.
* Stuck brake switch.
* Improper steering alignment or tire pull.
* An internal yaw rate/lateral accelerometer failure.
* An EBCM internal failure.

Reference Information
Schematic Reference

Antilock Brake System Schematics [1][2]Antilock Brakes / Traction Control Systems
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 Control Module References for scan tool information

Circuit/System Verification

1. Ignition ON, verify that DTC C0186, C0196, or C0455 is not set.

• If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle

2. Verify the yaw/lateral accelerometer is mounted properly.

• If not mounted properly, refer to Vehicle Yaw Sensor with Vehicle Lateral and Longitudinal Accelerometer Replacement Service and Repair.

3. Clear DTC, test drive vehicle under normal driving conditions.
4. Verify DTC C0252 is not set

• If the DTC is set replace the EBCM. If the DTC resets, replace the brake pressure modulator valve (BPMV).

Repair Instructions

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

* Brake Pressure Modulator Valve Replacement Service and Repair
* Vehicle Yaw Sensor with Vehicle Lateral and Longitudinal Accelerometer Replacement Service and Repair
* Control Module References Control Module References for EBCM replacement, setup, and programming