Circuit Description
The body control module (BCM) applies a ground through the brake pedal position sensor reference low circuit to the brake pedal position sensor. The BCM supplies a voltage signal through the 10-volt reference voltage circuit to the brake pedal position sensor. The brake pedal position sensor sends a variable voltage signal through the brake pedal position sensor signal circuit to the BCM as the brake pedal is applied.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC C0870 Brake Pedal Position Sensor Reference Output Circuit
Conditions for Running the DTC
The battery voltage must be between 9-16 volts.
Conditions for Setting the DTC
No change in the brake pedal position sensor signal to the BCM.
Action Taken When the DTC Sets
The stop lamps will not function correctly.
Conditions for Clearing the DTC
| • | The DTC will clear on current status after the condition for setting the fault is corrected. |
| • | A history DTC will clear after 100 consecutive ignition cycles without a fault present. |
| • | History or current DTCs can be cleared using a scan tool. |
Diagnostic Aids
Perform a visual inspection for loose or poor connections at all related components. Refer to Testing for Intermittent Conditions and Poor Connections .
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Exterior Lights Schematics Connector End View Reference: Master Electrical Component List | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
2 |
Does the scan tool display a change in the voltage? | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 3 |
3 | Test the 10-volt reference circuit of the brake pedal position sensor short to ground or an open. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 11 | Go to Step 4 |
4 | Test the instrument panel (I/P) dimming control circuit of the BCM for a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 11 | Go to Step 5 |
5 | Test the I/P dimming voltage reference of the BCM a short to ground or a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 11 | Go to Step 6 |
6 | Inspect for poor connections at the harness connector of the brake position sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 11 | Go to Step 7 |
7 |
Important: Always recalibrate the brake pedal position sensor after replacing the brake position sensor. Refer to Brake Pedal Position Sensor Calibration . Replace the brake pedal position sensor. Refer to Brake Pedal Position Sensor Replacement . Did you complete the replacement? | Go to Step 8 | -- |
8 |
Does DTC C0870 reset? | Go to Step 9 | Go to Step 11 |
9 | Inspect for poor connections at the harness connector of the BCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 11 | Go to Step 10 |
10 | Replace the BCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 11 | -- |
11 |
Does the DTC reset? | Go to Step 2 | System OK |
