The electronic brake control module (EBCM) triggers a yaw rate sensor test every 40 milliseconds and switches the sensor into test mode. The EBCM sends a test signal to the sensor via the test circuit. When the test is run, the measured yaw rate from the sensor to the EBCM must be in the range of 25 degrees per second that is greater or less then 7 degrees per second. At standstill, the vehicle yaw rate is zero. The yaw rate signal at standstill is called the offset. If calibration at standstill is not possible, a quick calibration during driving is done. The measured yaw rate is calibrated to a calculated reference yaw rate signal. Yaw rate sensor sensitivity is estimated by comparison of the reference yaw rate and the measured yaw rate during cornering.

Steering angle centering is the process by which the EBCM calibrates the steering sensor output so that the output reads zero when the steering wheel is centered. The vehicle stability enhancement system (VSES) steering angle sensor centering process is performed manually.

A malfunction is detected if one or more of the following conditions exist:

If equipped, the following actions occur:

Important:  Perform the steering angle sensor centering procedure after the diagnostic system check-vehicle is performed. Refer to Steering Angle Sensor Centering.

The following conditions may cause a malfunction:

Schematic Reference

Antilock Brake System Schematics

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

Drive vehicle above 40 km/h (25 mph), verify the scan tool Yaw Rate Sensor °/sec value in the scan tool VSES scan tool data. The specified value should change the display at a rate greater than 6-23 degrees per second per 40 milliseconds.

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 of resistance 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 2.3-2.7 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 2.3-2.7 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. 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 yaw rate sensor signal terminal 4 and 5 volts. Install a jumper wire between the ground 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 2.3-2.7 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.