C0186

DTC C0186

DTC Descriptor

DTC C0186
Lateral Accelerometer Circuit

Diagnostic Fault Information

Important: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Testing and Inspection





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 voltage range for the lateral accelerometer is 0.25 - 4.75 volts.

Conditions for Running the DTC
The ignition is ON.

Conditions for Setting the DTC
^ Lateral acceleration does not change when reducing speed from 30 km/h to 0 km/h and the condition occurs 16 times in a row.
^ The yaw/lateral combination sensor fails an internal self test.
^ Ignition voltage to the yaw/lateral combination sensor is less than 9.5 volts.
^ Communication is lost between the EBCM and the yaw/lateral combination sensor.

Action Taken When the DTC Sets
The driver information center (DIC) displays the Service Stabilitrak 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 yaw rate and lateral accelerometer sensors are located in one unit and cannot be serviced separately.

Reference Information
Schematic Reference
ABS Schematics

Connector End View Reference
ABS Connector End Views

Electrical Information Reference
^ Circuit Testing
^ Connector Repairs
^ Testing for Intermittent Conditions and Poor Connections
^ Wiring Repairs

Scan Tool Reference
Scan Tool Data List for EBCM

Circuit/System Testing
1. Ignition OFF, disconnect the yaw rate sensor/lateral accelerometer connector.
2. Ignition OFF, connect a 3-amp fused jumper wire between the 5-volt reference circuit and the lateral accelerometer signal circuit of the connector. Ignition ON, with the scan tool, verify lateral accelerometer signal parameter is 4.8 - 5.2 volts.
^ If over 5.2 volts, test lateral accelerometer signal circuit for short to voltage. If the circuits tests normal, replace the EBCM.
^ If under 4.8 volts, test lateral accelerometer signal circuit for open/high resistance or short to ground. If the circuits tests normal, replace the EBCM.

3. If all circuits test normal replace the yaw rate sensor/lateral accelerometer.

Repair Instructions

Important: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests





^ 1473
^ Control Module References for EBCM replacement, setup, and programming