C0870

DTC C0870

DTC DESCRIPTOR

DTC C0870 03
Device Voltage Reference Output 1 Circuit Voltage Below Threshold

DTC C0870 07
Device Voltage Reference Output 1 Circuit Voltage Above Threshold




DIAGNOSTIC FAULT INFORMATION

IMPORTANT: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Testing and Inspection

CIRCUIT/SYSTEM DESCRIPTION
The brake pedal position sensor is used to sense the action of the driver application of the brake pedal. The brake pedal position sensor provides an analog voltage signal that will increase as the brake pedal is applied. The body control module (BCM) provides a low reference signal and a 5-volt reference voltage to the brake pedal position sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the BCM will apply battery positive voltage to the stop lamps, center high mounted stop lamp (CHMSL), transmission control module (TCM), and engine control module (ECM). The stop lamps will not operate unless the ignition is in the ON position.

CONDITIONS FOR RUNNING THE DTC
Battery voltage must be between 9-16 volts.

CONDITIONS FOR SETTING THE DTC

DTC C0870 03
This DTC will set when the BCM detects the brake pedal position sensor voltage reference circuit is less than 4.5 volts for 0.5 second or greater.

DTC C0870 07
This DTC will set when the BCM detects the brake pedal position sensor voltage reference circuit is greater than 5.5 volts for 0.5 second or greater.

ACTION TAKEN WHEN THE DTC SETS
- The Service Vehicle Soon indicator is commanded ON.
- If the DTC sets while the vehicle is running, the BCM will activate the brake lights when the vehicles transmission is not in the PARK position and the vehicle is not accelerating.

CONDITIONS FOR CLEARING THE DTC
- The condition responsible for setting the DTC no longer exists.
- You issue a scan tool CLEAR DTCs command.
- A history DTC will clear once 50 malfunction-free ignition cycles have occurred.
- A DTC will not clear the current status until the next ignition cycle.

DIAGNOSTIC AIDS

IMPORTANT: The stop lamps will not illuminate unless the ignition is in the ON position. For more detailed information concerning stop lamp operation, refer to Exterior Lighting Systems Description and Operation.

CIRCUIT/SYSTEM TESTING
1. Ignition ON, use a scan tool to display DTCs for the BCM.
- If DTC C0870 03 is present, test the brake pedal position sensor reference voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the brake pedal position sensor.
2. Ignition OFF, disconnect the BCM C2 harness connector.
3. Verify that a test lamp does not illuminate between the brake pedal position sensor voltage reference circuit and ground.
- If the test lamp illuminates, repair the brake pedal position sensor voltage reference circuit for a short to voltage. If the circuit tests normal, replace the brake pedal position sensor.
4. If all circuits test normal, replace the BCM.

REPAIR INSTRUCTIONS

IMPORTANT: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

- Control Module References for BCM replacement, setup, and programming
- Brake Pedal Position Sensor Calibration
- Brake Pedal Position Sensor Replacement