Circuit Description
The body control module (BCM) applies a ground through the brake sensor reference low circuit to the brake pedal position sensor. The BCM supplies a 10-volt reference through the brake sensor reference voltage circuit to the brake position sensor. When the brake pedal is being applied, the brake pedal position sensor then sends a variable voltage signal through the brake sensor signal circuit to the BCM.
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 9.0-16.0 volts.
Conditions for Setting the DTC
| • | A short to ground or an open in the brake pedal position sensor voltage reference circuit is present. |
| • | A short battery positive voltage in the brake pedal position sensor voltage reference circuit is present. |
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. |
| • | A History or current DTC 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 |
Does the test light illuminate? | Go to Step 4 | Go to Step 5 |
4 | Test for a short to battery positive voltage in the brake pedal position sensor voltage reference circuit. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 11 | Go to Step 6 |
5 | Test for a short to ground on the brake pedal position sensor reference voltage circuit. 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 a high resistance or a poor connection 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: After replacing the brake pedal sensor, perform the calibration procedure. 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 a high resistance or a poor connection 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 |
