GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2006 🢒 Allure 🢒 Brakes 🢒 Antilock Brake System 🢒 DTC C0186

Circuit Description

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.

The lateral accelerometer sensor bias compensates for sensor mounting alignment errors and electronic signal errors.

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 speed is greater than 40 km/h (25 mph).

Conditions for Setting the DTC

Voltage at the lateral accelerometer signal output to the electronic brake control module (EBCM) falls outside the 0.25-4.75 volt range for more than 100 milliseconds.

Action Taken When the DTC Sets

If equipped, the following actions occur:

    • The EBCM disables the traction control system (TCS)/VSES for the duration of the ignition cycle.
    • A malfunction DTC is set.
    • The antilock brake system (ABS) indicator turns ON.

Conditions for Clearing the DTC
    • The condition for the DTC is no longer present.
    • A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.
    • Using a scan tool

Diagnostic Aids
    • A thorough inspection of the wiring system and connectors be performed. Failure to carefully and fully inspect the wiring system and connectors may result in misdiagnosis which may result in replacing good parts and the reappearance of the malfunction.
    • Inspection for poor connections, broken insulation, or a wire that is broken inside the insulation.
    • If an intermittent malfunction exists, refer to Testing for Intermittent Conditions and Poor Connections .

Test Description

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

  1. This step tests for specified voltage on the lateral accelerometer signal circuit.

    2.

  2. This step tests for B+ voltage on yaw/lateral accelerometer sensor.

    3.

  3. This step tests the ignition circuit for a high resistance or open.

    4.

  4. This step checks to see if the voltage was below or above the specified voltage.

    5.

  5. This step checks to see if the voltage was above the specified voltage.

    6.

  6. This step checks to see if the voltage was below the specified voltage.

    7.

  7. This step checks to see if the voltage was above the specified voltage.

    8.

  8. This step checks to see if the resistance of the ground circuit is less than 5 ohms.

    9.

  9. This step tests for a short to voltage on the 5-volt reference circuit.

    10.

  10. This step tests for a short to ground, a high resistance, or an open in the 5-volt reference circuit.

    11.

  11. This step tests for a short to ground, a high resistance, or an open in the lateral accelerometer signal circuit.

    12.

  12. This step tests for a short to voltage in the lateral accelerometer signal circuit.

    13.

  13. This step tests for a high resistance or an open in the ground circuit.

    14.

  14. This step checks the yaw/lateral accelerometer sensor connector for poor connections.

    15.

  15. This step checks the EBCM connector for poor connections.

Step

Action

Value(s)

Yes

No

Schematic Reference: Antilock Brake System Schematics

Connector End View Reference: Antilock Brake System Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Turn OFF the ignition.
  2. Disconnect the electronic brake control module (EBCM).
  3. Install the J 39700 Universal Pinout Box with the J 39700-530 Cable Adapter between the EBCM and the EBCM harness connector.
  4. Turn ON the ignition, with the engine OFF.
  5. Using the DMM, measure the voltage between pin 10 and pin 15 of the J 39700 .

Is the voltage within the specified value?

0.25-4.75 V

Go to Diagnostic Aids

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Disconnect the yaw/lateral accelerometer sensor.
  3. Turn ON the ignition, with the engine OFF.
  4. Using a DMM, measure the voltage between the ignition and ground circuits of the yaw/lateral accelerometer sensor.

Is the voltage in the specified value?

B+

Go to Step 5

Go to Step 4

4

Test the ignition circuit of the yaw/lateral accelerometer sensor for high resistance or an open.

Did you find and correct the condition?

--

Go to Step 19

Go to Power Distribution Schematics

5

  1. Reconnect the yaw/lateral accelerometer sensor.
  2. Using a DMM, measure the voltage between pin 10 and pin 15 of the J 39700 .

Is the voltage less than the specified value?

4.75 V

Go to Step 6

Go to Step 13

6

Using a DMM, measure the voltage between pin 10 and pin 15 of the J 39700 .

Is the voltage greater than the specified value?

0.25 V

Go to Step 7

Go to Step 12

7

Using a DMM, measure the voltage between the 5-volt reference circuit pin 16 and the ground circuit pin 15 on the J 39700 .

Does the voltage measure less than the specified value?

2 V

Go to Step 11

Go to Step 8

8

Using a DMM, measure the voltage between the 5-volt reference circuit pin 16 and ground circuit pin 15 on the J 39700 .

Does the voltage measure greater than the specified voltage?

3 V

Go to Step 10

Go to Step 9

9

  1. Turn OFF the ignition.
  2. Disconnect the negative battery cable.
  3. Measure the resistance from the ground circuit of the yaw/lateral accelerometer to a good ground.

Does the resistance measure less than the specified value?

5 ohms

Go to Step 16

Go to Step 14

10

Test the 5-volt reference circuit of the yaw/lateral accelerometer sensor for a short to voltage. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 19

Go to Step 15

11

Test the 5-volt reference circuit of the yaw/lateral accelerometer sensor for a short to ground, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 19

Go to Step 12

12

Test the lateral accelerometer signal circuit of the yaw/lateral accelerometer sensor for a short to ground, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 19

Go to Step 15

13

Test the lateral accelerometer signal circuit of the yaw/lateral accelerometer sensor for a short to voltage. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 19

Go to Step 15

14

  1. Disconnect the EBCM.
  2. Test the ground circuit of the yaw/lateral accelerometer sensor for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 19

Go to Step 15

15

Inspect for poor connections at the harness connector of the yaw/lateral accelerometer sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

--

Go to Step 19

Go to Step 17

16

Inspect for poor connections at the harness connector of the EBCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

--

Go to Step 19

Go to Step 18

17

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

Did you complete the replacement?

--

Go to Step 19

--

18

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

Did you complete the replacement?

--

Go to Step 19

--

19
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

--

Go to Step 2

System OK