For 1990-2009 cars

### Circuit/System Description

The vehicle stability enhancement system (VSES) is activated by the electronic brake control module (EBCM) calculating the desired yaw rate and comparing it to the actual yaw rate input. The desired yaw rate is calculated from measured steering wheel position, vehicle speed, and lateral acceleration. The difference between the desired yaw rate and actual yaw rate is the yaw rate error, which is a measurement of oversteer or understeer. If the yaw rate error becomes too large, the EBCM will attempt to correct the vehicle's yaw motion by applying differential braking to the left or right front wheel.

### Reference Information

#### Schematic Reference

Antilock Brake System Schematics

#### Connector End View Reference

Component Connector End Views

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References

### Circuit/System Testing

1. Inspect the mounting of the yaw rate sensor/lateral accelerometer.

⇒ | If the mounting of the yaw rate sensor/lateral accelerometer was incorrect or loose repair as required..

2. Install a scan tool.
3. Perform the Diagnostic Test Drive and observe the Yaw Rate Sensor Input parameter in the VSES data list.

⇒ | If the scan tool display suddenly increased or decreased without rapid turning of the vehicle, perform the diagnosis for DTC C0196.

⇒ | If a condition was not found in the diagnosis for DTC C0196, replace the EBCM.

4. Straighten the front wheels.
5. Slowly rotate the steering wheel in both directions and observe the Dual Analog Steering Position Sensor Test (SWPS) Input A and Dual Analog SWPS Input B in the DRP/ABS/TCS data list.

⇒ | If the scan tool display DID NOT change states as the steering wheel was rotated, replace the steering angle sensor (SAS).

6. Perform the Steering Position Sensor Test in order to verify if the steering angle sensor (SAS) is operating properly.

⇒ | If the SAS DID NOT pass the test, replace the SAS.

7. Place the vehicle on a level surface and observe the Lateral Accelerometer Input parameter in the VSES data list to verify that the Lateral Accelerometer Input parameter is within the valid range.

⇒ | If the scan tool DID NOT display within the specified range, replace the yaw rate sensor/lateral accelerometer.

8. Inspect the electronic brake control module (EBCM) for the correct part number.

⇒ | If the EBCM is not the correct part number, replace the EBCM.

9. Inspect the power steering gear for the correct part number.

⇒ | If the power steering gear is not the correct part number, replace the EBCM.

10. Inspect the wheel alignment of the vehicle.

⇒ | If the wheel alignment of the vehicle is outside of manufacturer specifications, perform a wheel alignment on the vehicle..

### Repair Instructions

• | Steering Angle Sensor Replacement .

• | Vehicle Yaw Sensor with Vehicle Lateral Accelerometer Replacement .

• | Electronic Brake Control Module Replacement .

• | Electronic Brake Control Module Programming and Setup .

• | Wheel Alignment Measurement .

• | Wheel Alignment Specifications .