GM Service Manual Online
For 1990-2009 cars only

Object Number: 598277  Size: MF
ABS Components
Precision Control System (PCS) (RPO JL4)

Circuit Description

During calibration of the offset of the pressure sensor signal, the pressure sensor signal offset value must be in the range of +/- 217.5 psi (15 Bar).

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 applied.
    • The ABS pump is not on.
    • The pressure sensor sensitivity is outside a predetermined range.

Action Taken When the DTC Sets

    • A malfunction DTC is set
    • ABS, TCS and PCS are disabled
    • ABS, TCS, SERVICE ENGINE SOON and PCS lamp indicators turn on
    • ABS braking distance increases

Conditions for Clearing the DTC

    • The condition for the DTC is no longer present.
    • A history DTC will clear after 124 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 Description

The number(s) below refer to the step number(s) on the diagnostic table.

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

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

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

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

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

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

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

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

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

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

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

  12. Checks to EBCM connector for poor connections.

Step

Action

Value(s)

Yes

No

1

Did you perform the ABS Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - ABS

2

  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 universal pinout box.

Is the voltage within the specified value?

0.25 V - 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 universal pinout box.

Is the voltage less than the specified value?

4.75 V

Go to Step 4

Go to Step 10

4

  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 universal pinout box.

Is the voltage greater than the specified value?

0.25 V

Go to Step 5

Go to Step 8

5

  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 6

Go to Step 7

6

  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 12

Go to Step 11

7

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 16

Go to Step 13

8

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 16

Go to Step 9

9

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 16

Go to Step 13

10

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 16

Go to Step 13

11

  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 16

Go to Step 13

12

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 16

Go to Step 14

13

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 16

Go to Step 15

14

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

Did you complete the replacement?

--

Go to Step 16

--

15

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

Did you complete the replacement?

--

Go to Step 16

--

16

  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