C0187

DTC C0186 or C0187

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.

DTC Descriptors
DTC C0186
- Lateral Accelerometer Circuit

DTC C0187
- Lateral Accelerometer Circuit Range/Performance

Circuit Description

The electronic brake control module (EBCM) uses the lateral accelerometer signal to determine the lateral forces acting on a vehicle during a turn or a skid. The EBCM uses the signal from the lateral accelerometer as one of the inputs to operate the vehicle stability enhancement system (VSES).

Conditions for Running the DTC

C0186

Ignition voltage is greater than 8 volts.

C0187
* Ignition voltage is greater than 8 volts.
* No yaw rate DTCs are present.
* Vehicle yaw rate is centered.

Conditions for Setting the DTC

C0186

Lateral accelerometer signal voltage is less than 0.18 volt or above 4.84 volts.

C0187

The EBCM will set the DTC when one or more of the following conditions have occurred:

* The lateral acceleration signal changes to rapidly based on vehicle dynamics.
* The internal calibration in the lateral accelerometer is out of range.
* The lateral accelerometer has failed and internal self check test.

Action Taken When the DTC Sets

If equipped, the following actions will occur:

* The EBCM disables VSES for the duration of the ignition cycle.
* The driver information center (DIC) displays the Service Stability System 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

The lateral accelerometer is packaged with the yaw rate sensor as a single component.

Reference Information
Schematic Reference

Antilock Brake System Schematics ([1][2]Antilock Brakes / Traction Control Systems)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

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

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the yaw rate and lateral acceleration sensor.
2. Test for less than 5 ohms of resistance between the low reference circuit terminal D and ground.

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

3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal B and ground.

• If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the EBCM.
• If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the EBCM.

4. Verify the scan tool Lateral Accelerometer Signal parameter is less than 0 volts.

• If greater than the specified range, test the signal circuit terminal E for a short to voltage. If the circuit tests normal, replace the EBCM.

5. Install a 3A fused jumper wire between the signal circuit terminal E and the 5-volt reference circuit terminal B. Verify the scan tool Lateral Accelerometer Signal is greater than 4.8 volts.

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

6. If all circuits test normal, test or replace the yaw rate and lateral acceleration sensor.

Repair Instructions

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

Vehicle Yaw Sensor with Vehicle Lateral Accelerometer Replacement (Service and Repair)