• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
• | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
• | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
5-Volt Reference | C0292 00 | C0292 00 | C0292 00 | -- |
Yaw Rate Sensor Signal | C0196 00 | C0196 00 | C0196 00 | -- |
Lateral Accelerometer Signal | C0186 00 | C0186 00 | C0186 00 | -- |
Low Reference | C0186 00 C0196 00 | C0186 00 C0196 00 | C0186 00 C0196 00 | -- |
Yaw Rate Frequency Signal (diagnostic) | C0196 28 | C0196 28 | C0196 28 | C0196 28 |
Longitudinal Accelerometer Sensor Signal | -- | -- | -- | -- |
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 yaw motion by applying differential braking to the wheels.
• | The ignition is ON. |
• | Ignition voltage is greater than 8 volts. |
• | The vehicle speed has reached at least 15 km/h (9 mph) from a stop more three times during the same ignition cycle. Then during the time the vehicle is stationary, the yaw rate signal value is more than 7 deg/sec for 2 seconds. |
• | When vehicle speed is more than 25 km/h (16 mph) in a turn the difference between the yaw rate, steering angle, lateral acceleration, and wheel speed sensor values are not correlated three consecutive times. |
• | Yaw rate changes greater than 20 deg/sec in 6 ms 4 times in 1 second. |
• | The yaw/lateral combination sensor fails an internal self test. |
The yaw frequency measured is not between 13400.0-14600.0 Hz for more than 200 msec.
• | The EBCM turns OFF the 5 volt reference circuit, until the ignition is cycled. |
• | A DIC message and/or a warning message may be displayed. |
• | The condition for setting the DTC is no longer present and the DTC is cleared with a scan tool. |
• | The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles. |
• | If DTC C0292 is set, diagnose that DTC first. |
• | If the yaw and lateral acceleometer sensor is disconnected, DTCs will set and the EBCM will not provide 5 volt reference. |
• | The yaw rate and lateral accelerometer sensors are located in one unit and cannot be serviced separately. |
• | A poor ground connection for the EBCM may cause this DTC to set. |
Antilock Brake System Schematics
Control Module References for EBCM
⇒ | If greater than 1 ohm, remove the EBCM connector and test for less than 1 ohm of resistance between the low reference terminal 22 and ground terminal 16 of the EBCM. If less than 1 ohm, then repair the low reference circuit or the EBCM ground circuit for a short to voltage or an open/high resistance. If greater than 1 ohm then replace the EBCM. |
⇒ | If all circuits test normal, replace the yaw and lateral acceleration sensor, and clear the yaw rate sensor offset value in the EBCM. |
⇒ | If the DTC sets again after replacing the yaw rate sensor/lateral accelerometer, replace the EBCM. |
⇒ | If the resistance is outside 4.5k +/- 2k ohms, remove the EBCM connector and measure the resistance between terminals 9 and 16 on the EBCM. If the measured resistance is outside 4.5k +/- 2k ohms, then replace the EBCM. Otherwise test the yaw rate diagnostic circuit terminal 4 for an open circuit or short to ground. This includes all bulkhead and splice connectors in the harness between the EBCM and the sensor. |
⇒ | If the yaw rate diagnostic circuit tests normal, replace the yaw and lateral acceleration sensor, and clear the yaw rate sensor DTCs in the EBCM. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for EBCM replacement, setup, and programming |