C0186

DTC C0186

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 Descriptor
DTC C0186 00
- Lateral Accelerometer Circuit

DTC C0186 08
- Lateral Accelerometer Circuit Signal Invalid

DTC C0186 09
- Lateral Accelerometer Circuit Rate of Change Above Threshold

DTC C0186 19
- Lateral Accelerometer Circuit Signal Amplitude Above Maximum

DTC C0186 1A
- Lateral Accelerometer Circuit Bias Level Out Of Range

DTC C0186 52
- Lateral Accelerometer Circuit Compare Failure




Diagnostic Fault Information






Circuit/System 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 00, 09, and 1A
* The ignition is ON.
* Ignition voltage is greater than 8 volts.



C0186 08
* Ignition voltage is ON.
* Ignition voltage is greater than 8 volts.
* The vehicle speed is greater than 0 km/h (0 mph).



C0186 19
* Ignition voltage is ON.
* Ignition voltage is greater than 8 volts.
* The vehicle is stationary.



C0186 52
* Ignition voltage is ON.
* Ignition voltage is greater than 8 volts.
* DTC C0196 is not set.
* The yaw rate sensor is less than 8 degrees/second.



Conditions for Setting the DTC

C0186 00, 09, and 1A

One of the following conditions exist:

* The lateral accelerometer sensor input voltage is less than 0.15 volt.
* The lateral accelerometer sensor input voltage is greater than 4.85 volts for 0.03 second.


C0186 08

The lateral accelerometer signal voltage does not increase at least 0.5 volt during the lateral accelerometer sensor self test.

C0186 09

The lateral accelerometer signal is greater than 108 m/s(2) (11 g) per second twice within 0.2 second.

C0186 19

The lateral accelerometer signal is greater than 4.9 m/s(2) (0.5 g) for 1 second.

C0186 1A

Both of the following conditions exist:

* The compensated bias value of the lateral accelerometer signal is greater than 2.9 m/s(2) (0.3 g).
* The yaw rate sensor is 0 degrees/second.


C0186 52

The slip rate error exceeds 4.9 m/s(2) (0.5 g) 60 times within one drive cycle.


Action Taken When the DTC Sets

If equipped, the following actions will occur:

* The EBCM disables the VSES for the duration of the ignition cycle.
* The driver information center (DIC) displays the SERVICE TRACTION SYSTEM message.
* The antilock brake system (ABS) and the traction control system (TCS) remain functional.



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 and lateral accelerometer sensor.
2. Test for less than 5 ohms 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 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 is greater than 4.8 volts.

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

6. If all circuits test normal, test or replace the yaw and lateral accelerometer 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)
* Control Module References (Programming and Relearning) for EBCM replacement, setup, and programming