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 Descriptor
DTC C0186 : Lateral Accelerometer CircuitDiagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
5-Volt Reference | C0252 | C0252 | C0252 | -- |
Yaw Rate Sensor Signal | C0196 | C0196 | C0196 | -- |
Lateral Accelerometer Signal | C0186 | C0186 | C0186 | -- |
Ground | C0186 C0196 | C0186, C0196 | C0186, C0196 | C0196 |
Yaw Rate Sensor test control | C0196 | C0196 | C0196 | -- |
Longitudinal Accelerometer Sensor Signal | -- | -- | -- | -- |
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
| • | 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 EBCM turns OFF the 5-volt reference circuit, until the ignition is cycled. |
| • | The driver information center (DIC) displays the Service Stabilitrak message. |
| • | The ABS indicator turns ON. |
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
| • | If the yaw and lateral acceleration sensor is disconnected, DTCs will set and the EBCM will not provide 5-volt reference. |
| • | The yaw rate and lateral accelerometer sensors are located in one unit and cannot be serviced separately. |
| • | A poor ground connection for the EBCM may cause this DTC to set. |
Reference Information
Schematic Reference
Antilock Brake System Schematics
Connector End View Reference
Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for EBCM
Circuit/System Testing
- If DTC C0252 is set, diagnose that DTC first.
- Ignition OFF, disconnect the yaw and lateral accelerometer sensor connector.
- Ignition OFF, test for less than 1 ohm between the ground circuit terminal and ground.
- Test the lateral accelerometer signal circuit terminal, the 5-volt reference circuit terminal, and the ground circuit terminal for an open/high resistance or a short to voltage or ground.
| ⇒ | If greater than 1 ohm, test the ground circuit terminal and the EBCM ground circuit terminal for a short to voltage or an open/high resistance. If the circuits test normal, replace the EBCM. |
| ⇒ | If all circuits test normal, replace the yaw and lateral accelerometer sensor, and clear the yaw rate sensor offset value in the EBCM. |
| ⇒ | If the DTC sets again after replacing the yaw and lateral accelerometer sensor, replace the EBCM. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for EBCM replacement, setup, and programming |
