Circuit Description
The brake pedal position sensor (BPP) 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 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 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 Diagnostic System Check - Vehicle? | Go to Step 2 | |
Perform the brake pedal position (BPP) 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 BPP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . 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 |
