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.


Conditions for Running the DTC

The ignition switch is in the ON position.


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 turn ON.
* 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 (w/JL4) (ABS Description and Operation (With RPO JL4))ABS Description and Operation (without JL4) (ABS Description and Operation (Without RPO JL4))
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 Verification

1. Ignition ON, observe the scan tool Lateral Accelerometer Signal Input parameter. The reading should be -16.000 to +15.995 m/s(2).
2. Ignition ON, observe the scan tool Yaw Rate Sensor parameter. The reading should be -115 to +114.101 deg/sec.



Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the yaw rate/lateral accelerometer.
2. Test for less than 2 ohms between the ground circuit terminal 6 and ground.

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

3. Ignition ON, test for 11.8-12.2 volts between the 12-volt reference circuit terminal 1 and ground.

• If less than the specified range, test the 12-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the EBCM.

4. Test for 5.5-7.0 volts between the CAN circuit terminal 3 and ground.

• If greater than the specified range, test the CAN circuit for a short to voltage. If the circuit tests normal, replace the EBCM.
• If less than the specified range, test the CAN circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the EBCM.

5. Test for 5.5-7.0 volts between the CAN circuit terminal 2 and ground.

• If greater than the specified range, test the CAN circuit for a short to voltage. If the circuit tests normal, replace the EBCM.
• If less than the specified range, test the CAN circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the EBCM.

6. Test for infinite ohm of resistance between the CAN circuit High, and Low terminals 2 and 3.

• If less than the specified range, test the CAN circuits for a shorted to each other. If the circuit tests normal, replace the EBCM.

7. If all circuits test normal, test or replace the yaw rate/lateral accelerometer 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