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.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC C0278 Brake Pedal Position Sensor Not Calibrated
Conditions for Running the DTC
| • | The EBCM control module must be powered. |
| • | This test is run continuously. |
Conditions for Setting the DTC
| • | The BPP sensor calibration procedure has never been performed. |
| • | The last BPP sensor calibration was unsuccessful. |
Action Taken When the DTC Sets
When DTC C0278 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. |
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | 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? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
Perform the brake pedal position sensor calibration procedure. Refer to Brake Pedal Position Sensor Calibration . 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 (BPP) 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 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? | Go to Step 6 | -- |
6 |
Does the DTC reset? | Go to Step 2 | System OK |
