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 wheels.

To correct for oversteer, differential braking is used on the left front or right front wheel brake. To correct for understeer, differential braking is used on the left rear or right rear wheel brake.

The EBCM performs different tests to detect a DTC condition. A malfunction is detected when the yaw rate sensor signal input voltage is less than 0.225 volts or greater than 4.775 volts for more than 100 milliseconds.

If equipped, the following actions occur:

The following conditions may cause a malfunction:

Schematic Reference

Connector End View Reference

Component Connector End Views

Description and Operation

ABS Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

1. Ignition OFF, disconnect the EBCM harness connector at the Yaw and Lateral Accelerometer Sensor.
2. Ignition OFF, with a DMM test for less than 5.0 ohms between the Vehicle Yaw and Lateral Accelerometer Sensor ground circuit terminal 6 and ground.

⇒	If greater than the specified range, with the DMM test the low reference circuit terminal 6 for an open/high resistance. If the circuit tests normal, replace the EBCM.

3. Ignition ON, with a DMM test for 0.225-4.775 volts between the Yaw and Lateral Accelerometer Sensor lateral accelerometer signal circuit terminal 5 and ground.

⇒	If less than the specified range, with the DMM test the lateral accelerometer signal circuit terminal 5 for a short to ground or an open/high resistance. If the circuit tests normal, replace the EBCM.

⇒	If greater than the specified range, with the DMM test the lateral accelerometer signal circuit terminal 5 for a short to voltage. If the circuit tests normal, replace the EBCM.

4. Ignition ON, with a DMM test for 0.225-4.775 volts between the Yaw and Lateral Accelerometer Sensor yaw rate signal circuit terminal 4 and ground.

⇒	If less than the specified range, with the DMM test the yaw rate signal circuit terminal 4 for a short to ground or an open/high resistance. If the circuit tests normal, replace the EBCM.

⇒	If greater than the specified range, with the DMM test the yaw rate signal circuit terminal 4 for a short to voltage. If the circuit tests normal, replace the EBCM.

5. Ignition ON, with the DMM, test for battery voltage at the Vehicle Yaw and Lateral Accelerometer Sensor Ignition 1 terminal 3 circuit and the ground circuit terminal 6.

⇒	If less than the specified value, test the ignition circuit terminal 3 for a open/high resistance. If the circuit tests normal, replace the EBCM.

6. Install a 3A fused jumper wire between the Yaw and Lateral Accelerometer Sensor signal circuit terminal and the Yaw and Lateral Accelerometer Sensor Volt reference circuit terminal 3. With a DMM, verify the voltage range is 2-3 volts.

⇒	If less than the specified value, test the 5-volt reference circuit terminal 3 for a short to ground or an open/high resistance. If the circuit tests normal, replace the EBCM.

⇒	If greater than the specified value, test the 5-volt reference circuit terminal 3 for a short to voltage. If the circuit tests normal, replace the EBCM.

7. If all circuits test normal, test or replace the Yaw and Lateral Accelerometer Sensor.

1. Install a 3A fused jumper wire between the Yaw and Lateral Accelerometer Sensor Volt reference terminal 1 and 5 volts. Install a jumper wire between the low reference circuit terminal 6 and ground.
2. Sweep the sensor through the entire range while monitoring the resistance between the signal circuit terminal 5 and the low reference circuit terminal 6. The voltage should vary between 0.25-4.75 volts without any spikes or dropouts.

⇒	If not within the specified range or is erratic, replace the Yaw and Lateral Accelerometer Sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.