Lighting

DTC C0870

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.



DTC Descriptor
DTC C0870
- Brake Pedal Position Sensor Circuit




Diagnostic Fault Information






Circuit/System Description

The body control module (BCM) provides a 10-volt reference voltage and a low reference signal to the brake pedal position sensor (BPPS). When the brake pedal is applied, the BPPS sends a variable voltage signal through the brake apply sensor signal circuit to the BCM. The voltage signal will increase as the brake pedal is further depressed. In response to this signal, the BCM applies battery positive voltage to the stop lamp switch signal circuit and the rear stop/turn lamp supply voltage circuits.


Conditions for Running the DTC

Ignition is ON


Conditions for Setting the DTC

The BCM detects an improper voltage on the 10-volt reference circuit


Action Taken When the DTC Sets

* The vehicle stop lamps will be inoperative
* Cruise control operation will be disabled



Conditions for Clearing the DTC

* The condition responsible for setting the DTC no longer exists
* A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred



Reference Information
Schematic Reference

Exterior Lights Schematics (Exterior Lights Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Exterior Lighting Systems Description and Operation (Exterior Lighting Systems Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning) for Scan Tool Information


Circuit/System Verification

Depress the brake pedal. The stop lamps should illuminate.


Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the BPPS.
2. Ignition ON, test for 9.8-10.2 volts between the 10-volt reference circuit terminal A and ground.

• If greater than the specified range, test the 10-volt reference circuit for a short to voltage. If the circuit tests normal, replace the BCM.


• If less than the specified range, test the 10-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.

3. If all circuits test normal, test or replace the BPPS.



Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Brake Pedal Position Sensor Replacement (Brake Pedal Position Sensor Replacement)
* Control Module References (Programming and Relearning) for BCM replacement, setup, and programming