C0186

DTC C0186

DTC Descriptor

DTC C0186
- Lateral Accelerometer Circuit

Diagnostic Fault Information

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview





Circuit/System Description

The lateral accelerometer and the yaw rate sensors are combined into one sensor external to the electronic brake control module (EBCM). The vehicle stability enhancement system (VSES) uses the lateral accelerometer input when calculating the desired yaw rate. The usable output voltage range for the lateral accelerometer is 0.25-4.75 volts.

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

* Lateral acceleration does not change when reducing speed from 30 km/h to 0 km/h and the condition occurs 16 times in a row.
* The yaw/lateral combination sensor fails an internal self test.
* Ignition voltage to the yaw/lateral combination sensor is less than 9.5 volts.
* Communication is lost between the EBCM and the yaw/lateral combination sensor.

Action Taken When the DTC Sets

* The EBCM turns OFF the 5-volt reference circuit, until the ignition is cycled.
* The driver information center (DIC) displays the Service Stabilitrak message.

Conditions for Clearing the DTC

* The condition for 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.

Diagnostic Aids

* If DTC C0292 is set, diagnose that DTC first.
* If the yaw and lateral accelerometer 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.

Reference Information

Schematic Reference

Antilock Brake System Schematics

Connector End View Reference

Antilock Brake System Connector End Views

Electrical Information Reference

* Circuit Testing
* Connector Repairs
* Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs

Scan Tool Reference

Scan Tool Data List for EBCM

Circuit/System Testing

1. Ignition OFF, disconnect the yaw rate sensor/lateral accelerometer connector.
2. Ignition OFF, test for less than 1 ohm of resistance between the low reference circuit and ground.

^ If greater than 1 ohm, test the low reference circuit and the EBCM ground circuit for a short to voltage or an open/high resistance. If the circuits test normal, replace the EBCM.

3. Test the lateral accelerometer signal circuit, the 5-volt reference circuit, and the low reference circuit for an open/high resistance or a short to voltage or ground.

^ If all circuits test normal, replace the yaw rate sensor/lateral accelerometer, 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.

Repair Instructions

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

* Yaw Rate Sensor/Lateral Accelerometer Replacement
* refer to programing and relearning Programming and Relearning