GM Service Manual Online
For 1990-2009 cars only

Circuit Description

During calibration of the offset of the pressure sensor signal, the pressure sensor signal offset value must be in the range of 1-15 Bar  (1-434 psi).

The pressure sensor is also monitored for sensitivity via a correlation between estimated vehicle deceleration and the pressure sensor signal. This is monitored over the course of numerous straight line non ABS braking stops.

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

    • The sensor signal offset value is out of range for more than 1 second.
    • The brake pedal is not applied.
    • The ABS pump is not on.
    • The brake pressure sensor sensitivity is outside a predetermined range.
    • The brake pressure sensor indicates low brake fluid pressure, and the brake pedal position sensor indicates brakes applied.

Action Taken When the DTC Sets

If equipped, the following actions occur:

    • The EBCM disables the ABS/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

Diagnostic Aids

    • A malfunctioning pressure sensor
    • A malfunctioning EBCM
    • Test the brake pedal position sensor for proper operation, and adjustment. A improperly adjusted BPPS will set the DTC.

Test Description

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

  1. Tests for DTCs set in the Body Control Module BCM Lighting Systems for a malfunctioning brake pedal position sensor BPPS.

  2. Tests for specified voltage on the brake pressure signal circuit.

  3. Checks to see if voltage was below specified voltage.

  4. Checks to see if voltage was above specified voltage.

  5. Checks to see if voltage was above specified voltage of 5 volt reference.

  6. Checks to see if 5 volt reference from EBCM is 5 volts.

  7. Checks to see if resistance of ground circuit is less than 5 ohms.

  8. Tests for short to voltage in the 5 volt reference circuit.

  9. Tests for a short to ground, a high resistance or an open in the 5 volt reference circuit.

  10. Tests for a short to voltage in the brake pressure sensor signal circuit.

  11. Tests for a high resistance or an open in the ground circuit.

  12. Checks to brake pressure sensor connector for poor connections.

  13. Checks to 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 ABS Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - ABS

2

After performing the ABS Diagnostic System Check, retrieve DTCs set for the brake pedal position sensor BPPS in Lighting Systems.

Did the BPPS set DTCs?

--

Go to Diagnostic Trouble Code (DTC) List in Lighting Systems

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Disconnect the 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 4

4

  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 less than the specified value?

4.75 V

Go to Step 5

Go to Step 11

5

  1. Turn OFF the ignition.
  2. 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.
  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?

0.25 V

Go to Step 6

Go to Step 9

6

  1. Disconnect the fused jumper wire.
  2. Measure the voltage between the 5 volt reference circuit of the brake pressure sensor and the ground circuit of the brake pressure sensor.

Does the voltage measure less than the specified value?

5 V

Go to Step 7

Go to Step 8

7

  1. Turn OFF the ignition.
  2. Disconnect the negative battery cable.
  3. Measure the resistance from the ground circuit of the brake pressure sensor to a good ground.

Does the resistance measure less than the specified value?

5 ohms

Go to Step 13

Go to Step 12

8

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

Did you find and correct the condition?

--

Go to Step 17

Go to Step 14

9

Test the 5 volt reference circuit of the brake pressure sensor for a short to ground, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 17

Go to Step 10

10

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 in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 17

Go to Step 14

11

Test the signal circuit of the brake pressure sensor for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 17

Go to Step 14

12

  1. Disconnect the EBCM.
  2. Test the ground circuit of the brake pressure sensor for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 17

Go to Step 14

13

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 in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 17

Go to Step 15

14

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

Did you find and correct the condition?

--

Go to Step 17

Go to Step 16

15

Replace the brake pressure sensor Brake Fluid Pressure Sensor Replacement .

Did you complete the replacement?

--

Go to Step 17

--

16

Important Before replacing the EBCM, inspect the brake pedal position sensor for proper adjustment, Refer to Brake Pedal Position Sensor Calibration Description and Operation in Lighting System.

Replace the EBCM. Refer to Electronic Brake Control Module Replacement .

Did you complete the replacement?

--

Go to Step 17

--

17

  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