GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2004 🢒 XLR 🢒 Vehicle Control Systems 🢒 Vehicle DTC Information 🢒 DTC C0278

Circuit Description

The BCM applies a ground through the brake sensor reference low circuit to the brake position sensor. The BCM supplies a 5-volt reference through the brake sensor reference voltage circuit to the brake position sensor. When the brake pedal is being applied, the brake position sensor then sends a variable voltage signal through the brake sensor signal circuit to the BCM.

Conditions for Running the DTC

The battery voltage must be between 9.0-16.0 volts.

Conditions for Setting the DTC

DTC C0278 00 will set if the brake position sensor is out of calibration.

Action Taken When the DTC Sets

The Service Vehicle Soon indicator is commanded ON.

Conditions for Clearing the DTC
    • This DTC will clear on current status after the condition for setting the fault is corrected.
    • A history DTC will clear after 100 consecutive ignition cycles with out a fault present.
    • History and current DTCs can be cleared using a scan tool.

Diagnostic Aids
    • If DTC C0278 00 sets then recalibrate the brake position sensor.
    •  Perform a visual inspection for a loose or poor connection at all related components. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Step

Action

Yes

No

Schematic Reference: Exterior Lights Schematics

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

1

Did you perform the Diagnostic System Check?

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.

Does the scan tool display DTC C0278 00?

Go to Step 3

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

3

Recalibrate the brake position sensor.

Did you complete the repair?

Go to Step 4

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4
  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.

Does the scan tool display DTC C0278 00?

Go to Step 5

Go to Step 6

5

Important: After replacing the brake position sensor, perform the calibration procedure. Refer to Brake Pedal Position Sensor Calibration .

Replace the brake position sensor. Refer to Brake Pedal Position Sensor Replacement .

Did you complete the replacement?

Go to Step 6

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6
  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?

Go to Step 2

System OK