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 Descriptors
DTC C0186 00
- Lateral Accelerometer Circuit

DTC C0186 5A
- Lateral Accelerometer Circuit Erratic




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 signal is a serial data signal CAN high and CAN low serial data circuits.


Conditions for Running the DTC

The Ignition is ON.


Conditions for Setting the DTC

* The yaw/lateral combination sensor fails an internal self test.
* Communication is lost between the EBCM and the yaw/lateral combination sensor.



Action Taken When the DTC Sets

One or more of the following actions may occur:

* The vehicle stability enhancement system (VSES) is disabled.
* Traction control system (TCS) is disabled.
* The TCS/VSES indicators illuminate.
* The driver information center (DIC) displays the Service Traction Control, and or Service Stabilitrak message.



Conditions for Clearing the DTC

* The condition for the DTC is no longer present.
* The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.



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 scan tool information


Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the yaw rate/lateral accelerometer sensor.
2. Test for less than 1 ohm between the low reference circuit terminal 1 and ground.

• If greater than the specified range, test for an open/high resistance in the low reference circuit. If the circuit tests normal, replace the EBCM.

3. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal 4 and ground.

• If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the EBCM.

4. Ignition OFF, disconnect the harness connector at the EBCM.
5. Ignition ON, test for less than 1 volt between the following circuits listed below and ground at the EBCM harness connector.

* CAN bus high serial data circuit terminal 37
* CAN bus low serial data circuit terminal 24


• If greater than the specified value, test the appropriate serial data circuit for a short to voltage.

6. Ignition OFF, test for infinite resistance between the following circuits listed below and ground at the EBCM harness connector.

* CAN bus high serial data circuit terminal 37
* CAN bus low serial data circuit terminal 24


• If not the specified value, test the appropriate serial data circuit for a short to ground.

7. Test for less than 1 ohm between the following circuits listed below.

* CAN bus high serial data circuit terminal 37 and terminal 3
* CAN bus low serial data circuit terminal 24 and terminal 2


• If greater than the specified range, test the appropriate serial data circuit for an open/high resistance.

8. Test for infinite resistance between the following circuits listed below at the EBCM harness connector.

* CAN bus high serial data circuit terminal 37
* CAN bus low serial data circuit terminal 24


• If not the specified value, test the appropriate serial data circuit for a short together.

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



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