GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2007 🢒 LaCrosse 🢒 DTC 🢒 DTC C0131

Circuit Description

The electronic brake control module (EBCM) uses input from the brake pressure sensor for more accurate control during a vehicle stability enhancement system (VSES) event.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC C0131 Antilock Brake System (ABS)/Traction Control System (TCS) Pressure Circuit

Conditions for Running the DTC
    • DTC C0870 is not set.
    • The ignition is ON.
    • The vehicle speed is greater than 40 km/h (24 mph).

Conditions for Setting the DTC

Voltage at the pressure sensor signal output to the EBCM falls outside the 0.25-4.75 volts range for more than 100 milliseconds.

Action Taken When the DTC Sets

If equipped, the following actions occur:

    • The EBCM disables the antilock brake system (ABS)/traction control system (TCS)/VSES for the duration of the ignition cycle.
    • A malfunction DTC will set.
    • The ABS indicator turns ON.
    • The Stability Off indicator turns ON.
    • The red BRAKE warning indicator could turn 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, clear DTC function.

Diagnostic Aids
    • A thorough inspection of the wiring system and connectors should 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 brake pressure signal circuit.

    2.

  2. This step checks to see if voltage was below specified voltage.

    3.

  3. This step checks to see if voltage was below specified voltage.

    4.

  4. This step checks to see if voltage was above specified voltage of the 5-volt reference.

    5.

  5. This step tests for a short to ground in the 5-volt reference circuit.

    6.

  6. This step tests for a short to voltage in the 5-volt reference circuit.

    7.

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

    8.

  8. This step tests for a short to voltage, a high resistance, or an open in the brake pressure sensor signal circuit.

    9.

  9. This step tests for a high resistance or an open in the ground circuit of the brake pressure sensor.

    10.

  10. This step checks the brake pressure sensor connector for poor connections.

    11.

  11. 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?

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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 17 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 brake pressure sensor.
  3. Turn ON the ignition, with the engine OFF.
  4. Using the DMM, measure the voltage between pin 17 and pin 15 of the J 39700 .

Is the voltage greater than the specified value?

5 V

Go to Step 9

Go to Step 4

4

  1. Turn OFF the ignition.
  2. Connect a 3-amp fused jumper wire between the signal circuit of the brake pressure sensor and the 5-volt reference circuit of the brake pressure sensor.
  3. Turn ON the ignition, with the engine OFF.
  4. Using the DMM, measure the voltage between pin 17 and pin 15 of the J 39700 .

Is the voltage less than the specified value?

0.25 V

Go to Step 8

Go to Step 5

5

  1. Turn OFF the ignition.
  2. Disconnect the fused jumper wire.
  3. Connect a 3-amp fused jumper wire between the 5-volt reference circuit of the brake pressure sensor and the signal circuit of the brake pressure sensor.
  4. Measure the voltage between the 5-volt reference circuit of the brake pressure sensor and the signal circuit of the brake pressure sensor.

Is the voltage measured greater than the specified value?

5 V

Go to Step 7

Go to Step 6

6

Test the 5-volt reference circuit of the brake pressure sensor for a short to ground. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 15

Go to Step 12

7

Test the 5-volt reference circuit of the brake pressure sensor for a short to voltage. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 15

Go to Step 11

8

Test the signal circuit of the brake pressure 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 15

Go to Step 12

9

Test the signal circuit of the brake pressure sensor for a short to voltage, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 15

Go to Step 10

10

Test the ground circuit of the brake pressure 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 15

Go to Step 12

11

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

Did you find and correct the condition?

--

Go to Step 15

Go to Step 13

12

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 15

Go to Step 14

13

Replace the brake pressure sensor. Refer to Brake Pressure Modulator Valve Pressure Sensor Replacement .

Did you complete the replacement?

--

Go to Step 15

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14

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

Did you complete the replacement?

--

Go to Step 15

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15
  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