GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2006 🢒 Yukon Denali 🢒 Accessories 🢒 Navigation Systems 🢒 DTC C0186

Circuit Description

The electronic brake control module (EBCM) supplies 5 volts to the yaw rate sensor/lateral accelerometer. When the vehicle is not moving, or is being driven in a stable, straight line, lateral acceleration is 0 m/sec/sec (0 ft/sec/sec) and the lateral accelerometer signal voltage is very near 2.5 volts. This is referred to as lateral accelerometer bias voltage. Making a turning maneuver causes the lateral accelerometer signal voltage to increase, or decrease, depending on the direction of the turn. The sharper the turn, the greater the change in signal voltage.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC C0186 Lateral Accelerometer Circuit

Conditions for Running the DTC
    • The ignition is ON.
    • The vehicle stability enhancement system (VSES) sensors have been successfully initialized or the message center has displayed the stability system disabled message due to an unsuccessful initialization attempt. Refer to ABS Description and Operation for a complete explanation of VSES sensor initialization.
    • The vehicle is being driven relatively straight and level at a speed greater than 11 km/h (7 mph), before performing a stable turning maneuver.

Conditions for Setting the DTC

Any of the following conditions may cause the DTC to set:

    • Open lateral accelerometer circuitry is detected.
    • Shorted lateral accelerometer circuitry is detected.
    • An erratic lateral accelerometer signal is detected.
    • The EBCM detects that the lateral accelerometer sensor signal does not correspond with signals from other sensors.

Action Taken When the DTC Sets
    • The EBCM disables the VSES.
    • The message center displays the service stability system message.

Conditions for Clearing the DTC

The conditions for setting the DTC are no longer present and you use the scan tool Clear DTCs function.

Diagnostic Aids
    • Inspect the vehicle for proper wheel alignment. Ensure the vehicle does not pull toward the left or right while driving straight forward on a level surface.
    • Communicate with the customer to determine the conditions under which the message center displays the Service Stability System message. Learning the conditions under which the DTC sets may help you duplicate the failure.
    • Use the Snapshot function on the scan tool in order to assist you in locating an intermittent malfunction.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step tests the sensor circuitry in the high voltage range.

  2. This step tests the sensor circuitry in the low voltage range.

Step

Action

Values

Yes

No

Schematic Reference: Antilock Brake System Schematics

Connector End View Reference: Antilock Brake System Connector End Views

Important: 

   • If DTC C0292 is set, diagnose C0292 before proceeding with diagnostics for C0186.
   • If DTC C0196 is set, diagnose C0196 before proceeding with diagnostics for C0186.
   • Always use connector test adapters when performing tests to avoid damage to delicate connector terminals.
   • Do not turn OFF the ignition during this diagnostic procedure unless the step in the table instructs you to do so. The scan tool may display some incorrect data if the ignition is cycled.

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle

2
  1. Use the scan tool to clear the DTCs.
  2. Turn OFF the ignition for 5 seconds.
  3. Turn ON the ignition.
  4. Operate the vehicle within the Conditions for Running the DTC, as specified in the supporting text.

If the DTC is current, test the lateral accelerometer signal circuit for the following condition:

An open circuit

Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 10

Go to Step 3

3

  1. Turn ON the ignition.
  2. Disconnect the yaw rate sensor/lateral accelerometer harness connector. Refer to Vehicle Yaw Sensor with Vehicle Lateral Accelerometer Replacement .
  3. Select the VSES Data Display function on the scan tool.
  4. Connect a 3-amp fused jumper wire between the yaw rate sensor/lateral accelerometer 5-volt reference circuit and the lateral accelerometer signal circuit. Refer to Using Fused Jumper Wires .
  5. Observe the Lateral Accelerometer Sensor Input on the scan tool.

Is the Lateral Accelerometer Sensor Input voltage greater than the specified value?

4.4 V

Go to Step 4

Go to Step 5

4

  1. Remove the fused jumper wire from the yaw rate sensor/lateral accelerometer harness connector.
  2. Observe the Lateral Accelerometer Sensor Input on the scan tool.

Is the Lateral Accelerometer Sensor Input voltage less than the specified value?

0.6 V

Go to Step 6

Go to Step 9

5

Test the lateral accelerometer signal circuit for the following conditions:

    • A high resistance
    • A short to ground

Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 10

Go to Step 7

6
  1. Inspect for poor connections at the harness connector of the yaw rate sensor/lateral accelerometer. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
  2. Ensure the yaw rate sensor/lateral accelerometer is mounted securely and that the mounting bracket is not bent or otherwise damaged.

Did you find and correct the condition?

--

Go to Step 10

Go to Step 8

7

Inspect for poor connections at the harness connector of the electronic brake control module (EBCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

--

Go to Step 10

Go to Step 9

8

Important: The Yaw Rate Reference Table Reset Procedure must be performed when you are instructed to do so during the Yaw Rate Sensor/Lateral Accelerometer Replacement procedure.

Replace the yaw rate sensor/lateral accelerometer. Refer to Vehicle Yaw Sensor with Vehicle Lateral Accelerometer Replacement .

Did you complete the replacement?

--

Go to Step 10

--

9

Replace the EBCM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

--

Go to Step 10

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10
  1. Use the scan tool Clear All Class 2 DTCs function to clear all of the DTCs from all modules.
  2. Turn OFF the ignition for 5 seconds.
  3. Turn ON the ignition.
  4. Operate the vehicle within the Conditions for Running the DTC, as specified in the supporting text.

Does the DTC reset?

--

Go to Step 3

System OK