GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using the diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC C0186 00: Lateral Accelerometer Circuit

DTC C0186 5A: Lateral Accelerometer Circuit Erratic

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Lateral Accelerometer Supply Voltage Circuit

C0186 00

C0186 00

C0186 00

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Lateral Accelerometer CAN Bus High Circuit

C0186 00

C0186 00

C0186 00

C0186 5A

Lateral Accelerometer CAN Bus Low Circuit

C0186 00

C0186 00

C0186 00

C0186 5A

Lateral Accelerometer Ground Circuit

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C0186 00

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Circuit/System Description

The electronic brake control module (EBCM) supplies 12 V reference circuit to the yaw-rate sensor assembly, and a ground through the yaw-rate sensor low reference circuit, and both circuits are shared with the steering angle sensor. The EBCM, yaw-rate sensor assembly and steering angle sensor share a common 12 V supply voltage circuit.

The yaw-rate sensor produces signal output voltage that corresponds to the vehicle rotation around its vertical axis.

Conditions for Running the DTC

The ignition switch is in the ON position.

Conditions for Setting the DTC

    • The EBCM detects a fault in the lateral acceleration signal voltage output.
    • Both brake lamps are faulty.

Action Taken When the DTC Sets

One or more of the following actions may occur:

    • The EBCM disables ESP for the duration of the ignition cycle.
    • The ABS/TCS indicators turn ON.
    • The Trac-Off indicator turns ON.

Conditions for Clearing the DTC

    • The condition for the DTC is no longer present.
    • The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.

Diagnostic Aids

Possible causes of this DTC are as follows:

    • CAN HI and CAN LO circuits shorted together
    • CAN HI or CAN LO circuit shorted to ground
    • CAN HI or CAN LO circuit shorted to voltage

Reference Information

Schematic Reference

Antilock Brake System Schematics

Connector End View Reference

Component 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 Verification

With scan tool installed, clear the DTCs then drive the vehicle in a straight line at a speed greater than 15 km/h (9 mph). If the DTC did not set as a current DTC see diagnostic aids.

Circuit/System Testing

  1. Ignition OFF, disconnect the yaw-rate/lateral accelerometer connector.
  2. Test the yaw-rate/lateral sensor reference voltage circuit for a short to voltage, short to ground, an open or high resistance.
  3. If the reference voltage circuit did not test normal, repair the circuit.
  4. Test the yaw/lateral sensor ground circuit for an open or high resistance.
  5. If the reference ground circuit did not tests normal, repair the circuit.
  6. Test the yaw/lateral sensor CAN HI and LO circuit for a short to voltage, short to ground, an open or high resistance.
  7. If the yaw/lateral CAN HI and LO circuits did not test normal repair the circuit.
  8. Ignition ON, test the yaw/lateral sensor reference voltage circuit for 12 volts, and the ground circuit for an open or high resistance.
  9. If the yaw/lateral 12 volt reference and ground circuits test normal replace the yaw/lateral sensor.
    If the yaw/lateral 12 volt reference and ground circuits did not test normal replace the EBCM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for EBCM replacement, setup and programming