Diagnostic Instructions
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
Connector End View Reference
Component Connector End Views
Description and Operation
ABS Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the yaw rate and lateral acceleration sensor.
- 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. |
- 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. |
- 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. |
- 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. |
- If all circuits test normal, test or replace the yaw rate and lateral acceleration sensor.
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic procedure.
Vehicle Yaw Sensor with Vehicle Lateral Accelerometer Replacement
