Circuit Description
The brake pedal position sensor is a potentiometer. The electronic brake control module (EBCM) supplies a 5-volt reference circuit and low reference circuit to the brake pedal position sensor. The brake pedal position sensor signal circuit is a direct input to the EBCM. The EBCM determines the brake pedal position based on the voltage from the brake pedal position sensor. The EBCM converts the brake pedal position sensor feed back voltage to a digital signal and puts it on the class 2 communication bus.
Conditions for Running the DTC
| • | The EBCM control module must be powered. |
| • | This test is run continuously. |
Conditions for Setting the DTC
| • | The brake pedal position sensor calibration procedure has never been performed. |
| • | The last brake pedal position sensor calibration was unsuccessful. |
Action Taken When the DTC Sets
When DTC C0278 is set the following will occur:
| • | The engine drive control is disabled. |
| • | 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. |
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Interior Lights Schematics and Antilock Brake System Schematics Connector End View Reference: Master Electrical Component List | |||
1 | Did you perform the Lighting Systems Diagnostic System Check? | Go to Step 2 | |
Perform the brake pedal position sensor calibration procedure. Refer to Brake Pedal Position Sensor Calibration Description and Operation . Did you complete the calibration procedure? | Go to Step 3 | -- | |
3 |
Does the DTC reset? | Go to Step 4 | Go to Step 6 |
4 | Inspect for poor connections at the harness connector of the brake pedal position 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 6 | Go to Step 5 |
5 |
Important: Always perform the calibration procedure for the brake pedal position sensor. Refer to Brake Pedal Position Sensor Calibration Description and Operation . Replace the brake pedal position sensor. Refer to Brake Pedal Position Sensor Replacement . Did you complete the replacement? | Go to Step 6 | -- |
6 |
Does the DTC reset? | Go to Step 2 | System OK |
