C0186

DTC C0186

Diagnostic Instructions

* 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.



DTC Descriptor
DTC C0186
- Lateral Accelerometer Circuit




Diagnostic Fault Information






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 the yaw and lateral acceleration 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 ([1][2]Antilock Brakes / Traction Control Systems)
Connector End View Reference

Component Connector End Views
Description and Operation

ABS Description and Operation (Description and Operation)
Electrical Information Reference

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

Scan Tool Reference

Control Module References for EBCM


Circuit/System Testing

1. If DTC C0292 is set, diagnose that DTC first.
2. Ignition OFF, disconnect the yaw and lateral acceleration sensor connector.
3. Ignition OFF, test for less than 1 ohm of resistance between the low reference circuit terminal 6 and ground.

• If greater than 1 ohm, test the low reference circuit terminal 6 and the EBCM ground circuit terminal 16 for a short to voltage or an open/high resistance. If the circuits test normal, replace the EBCM.

4. Test the lateral accelerometer signal circuit terminal 2, the 5 volt reference circuit terminal 1, and the low reference circuit terminal 6 for an open/high resistance or a short to voltage or ground.

• 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 and lateral acceleration sensor, replace the EBCM.




Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

* Vehicle Yaw Sensor with Vehicle Lateral Accelerometer Replacement (Service and Repair)
* Control Module References for EBCM replacement, setup, and programming