For 1990-2009 cars only
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 00: Lateral Accelerometer CircuitDiagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
5-Volt Reference | C0292 00 | C0186 00, C0196 00, C0196 28 | C0292 00* | -- |
Yaw Rate Sensor Signal | C0196 00 | C0196 00 | C0196 00**, C0196 28**, C0292 00* | -- |
Lateral Accelerometer Signal | C0186 00 | C0186 00 | C0186 00**, C0292 00* | -- |
Yaw Rate Frequency Signal | -- | -- | C0196 28 | C0196 28 |
Low Reference | -- | C0196 28 | -- | -- |
* DTC sets when shorted to 12 volts ** DTC sets when shorted to 5 volts | ||||
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 EBCM turns OFF the 5-volt reference circuit, until the ignition is cycled. |
| • | The antilock brake system (ABS) indicator illuminates. |
| • | The vehicle dynamics caution (VDC) indicator illuminates. |
| • | The driver information center (DIC) displays Service Stabilitrak. |
Conditions for Clearing the DTC
| • | The condition for the DTC is no longer present. |
| • | The ABS indicator may remain illuminated after repairs are made and DTCs are cleared, until the vehicle is operated at speeds greater than 13 km/h (8 mph) and the self test is completed. |
| • | The EBCM clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles. |
Diagnostic Aids
| • | If the yaw and lateral accelerometer 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. |
| • | If DTC C0292 is set, diagnose that DTC first. |
Reference Information
Schematic Reference
Antilock Brake System Schematics
Connector End View Reference
Antilock Brake System Connector End Views
Electrical Information Reference
Scan Tool Reference
Scan Tool Data List for EBCM
Circuit/System Testing
- Visually inspect the yaw rate sensor/lateral accelerometer for proper and secure mounting.
- Ignition OFF, disconnect the harness connector at the yaw rate sensor/lateral accelerometer.
- Ignition OFF for 30 seconds, test for less than 15 ohms between the low reference circuit terminal 6 and ground.
- Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 1 and ground.
- Ignition OFF, disconnect the harness connector at the EBCM.
- Ignition ON, test for less than 1 volt between the following signal circuits and ground:
- Test for less than infinite resistance between the following signal circuits and ground:
- Test for less than 2 ohms between the following signal circuit terminals:
- If all circuits test normal, test or replace the yaw rate sensor/lateral accelerometer. After replacement and programming, operate the vehicle within the conditions for running the DTC and verify DTC C0186 00 does not set.
| ⇒ | If the sensor is improperly secured, remove and properly install the sensor. |
| ⇒ | If greater than the specified range, test the low reference circuit for 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. |
| ⇒ | 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. |
| • | Yaw rate signal terminal 3 |
| • | Lateral accelerometer signal terminal 2 |
| ⇒ | If greater than the specified range, test the signal circuit for a short to voltage. |
| • | Yaw rate signal terminal 3 |
| • | Lateral accelerometer signal terminal 2 |
| ⇒ | If not the specified value, test the signal circuit for a short to ground. |
| • | Terminal 3 at the sensor harness connector and terminal 37 at the EBCM harness connector |
| • | Terminal 2 at the sensor harness connector and terminal 8 at the EBCM harness connector |
| ⇒ | If greater than the specified range, test the signal circuit for an open/high resistance. |
| ⇒ | If the DTC sets, replace the EBCM. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for EBCM replacement, setup, and programming |
