C0186 - ABS

Antilock Brake System

Diagnostic Information and Procedures

DTC C0186

Circuit Description

The EBCM supplies 5.0 volts to the yaw rate sensor/lateral accelerometer. When the vehicle is not moving, or is being driven in a stable, straight line, lateral acceleration is 0 m/sec/sec (0 ft/sec/sec) and the lateral accelerometer signal voltage is very near 2.5 volts. This is referred to as lateral accelerometer bias voltage. Making a turning maneuver causes the lateral accelerometer signal voltage to increase, or decrease, depending on the direction of the turn. The sharper the turn, the greater the change in signal voltage.

Conditions for Running the DTC

- The ignition is ON.
- The VSES sensors have been successfully initialized or the message center has displayed the stability system disabled message due to an unsuccessful initialization attempt. Refer to ABS Description and Operation (W/O JL4) ABS Description and Operation (W/JL4) for a complete explanation of VSES sensor initialization.
- The vehicle is being driven relatively straight and level at a speed greater than 11 km/h (7 mph), before performing a stable turning maneuver.

Conditions for Setting the DTC

Any of the following conditions may cause the DTC to set.
- Open lateral accelerometer circuitry is detected.
- Shorted lateral accelerometer circuitry is detected.
- An erratic lateral accelerometer signal is detected.
- The EBCM detects that the lateral accelerometer sensor signal does not correspond with signals from other sensors.

Action Taken When the DTC Sets

- The EBCM disables the VSES.
- The message center displays the service stability system message.

Conditions for Clearing the DTC

The Conditions for Setting the DTC are no longer present and you use the scan tool Clear DTC's function.

Diagnostic Aids

- Inspect the vehicle for proper wheel alignment. Ensure the vehicle does not pull toward the left or right while driving straight forward on a level surface.
- Communicate, with the customer, to determine the conditions under which the message center displays the Service Stability System message. Learning the conditions under which the DTC sets may help you duplicate the failure.
- Use the Snapshot function on the scan tool in order to assist you in locating an intermittent malfunction.

Test Description

The numbers below refer to the step numbers on the diagnostic table.
3. This step tests the sensor circuitry in the high voltage range.
4. This step tests the sensor circuitry in the low voltage range.

DTC C0186 Steps 1 - 5:

DTC C0186 Steps 6 - 10: