GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The brake pedal position (BPP) sensor is a potentiometer. The electronic brake control module (EBCM) supplies a 5-volt reference circuit and low reference circuit to the BPP sensor. The BPP sensor signal circuit is a direct input to the EBCM. The EBCM determines the BPP based on the voltage from the BPP sensor. The EBCM converts the BPP sensor feed back voltage to a digital signal and puts it on the class 2 communication bus. If the voltage is greater than 4.9 volts, then DTC C0284 will set.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC C0284 Brake Pedal Position Sensor Circuit High

Conditions for Running the DTC

    • The EBCM control module must be powered.
    • This test is run continuously.

Conditions for Setting the DTC

The feedback voltage is greater than 4.9 volts for more than 610 milliseconds.

Action Taken When the DTC Sets

When DTC C0284 is set the following will occur:

    • The vehicle will not start.
    • The panic brake assist is disabled.
    • The traction control system is disabled.
    • The vehicle stability enhancement system is disabled.
    • The service vehicle soon lamp will illuminate.

Conditions for Clearing the DTC

    • The current DTC will clear when the fault is no longer present.
    • A history DTC clears after 100 consecutive ignition cycles in which no faults have occurred.
    • Clear the DTC with a scan tool.

Step

Action

Value(s)

Yes

No

Schematic Reference: Exterior Lights Schematics and Antilock Brake System Schematics in Antilock Brake System

Connector End View Reference: Master Electrical Component List in Wiring Systems

1

Did you perform the Diagnostic System Check - Vehicle?

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Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the brake pedal position (BPP) Sensor A/D Conversi parameter.

Is the BPP Sensor A/D Conversi parameter within the specified range?

0.25-4.9 V

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Connect a 3-amp fused jumper wire between the signal circuit of the BPP sensor and the low reference circuit of the BPP sensor.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the BPP sensor data parameter.

Does the scan tool indicate that the BPP sensor data parameter is less than the specified value?

0.25 V

Go to Step 5

Go to Step 4

4

Test the low reference circuit of the BPP 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?

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Go to Step 9

Go to Step 6

5

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

Did you find and correct the condition?

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Go to Step 9

Go to Step 7

6

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 in Wiring Systems.

Did you find and correct the condition?

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Go to Step 9

Go to Step 8

7

Important: Always perform the calibration procedure for the BPP sensor. Refer to Brake Pedal Position Sensor Calibration .

Replace the BPP sensor. Refer to Brake Pedal Position Sensor Replacement .

Did you complete the replacement?

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Go to Step 9

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8

  1. Replace the EBCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.
  2. Perform the setup procedure for the EBCM.

Did you complete the replacement?

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Go to Step 9

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9

  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC.

Does the DTC reset?

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Go to Step 2

System OK