Circuit Description
The brake pedal position (BPP) sensor is an input to the body control module (BCM). The BCM then sends a serial data message to the electronic brake control module (EBCM) and other electronic control modules. The BPP sensor is a potentiometer type sensor with a 5-volt reference circuit and a low reference circuit. The BCM supplies the 5-volt reference to the BPP.
DTC Descriptors
This diagnostic procedure supports the following DTC:
DTC C0161 ABS/TCS Brake Switch Circuit
This vehicle has DTCs which include DTC Symptoms. For more information on DTC Symptoms, refer to DTC Symptom Description .
DTC Symptom | DTC Symptom Descriptor |
|---|---|
11 | Above Maximum Threshold |
12 | Below Minimum Threshold |
Conditions for Running the DTC
C0161 11
| • | The ignition is ON. |
| • | The vehicle speed is greater than 16 km/h (10 mph) |
| • | The ignition voltage is greater than 8 volts. |
C0161 12
| • | The ignition is ON. |
| • | The ignition voltage is greater than 8 volts. |
Conditions for Setting the DTC
C0161 11
| • | The brake pedal is sensed as applied. |
| • | The vehicle speed is greater than 40 km/h (25 mph). |
| • | The vehicles acceleration exceeds 8 km/h/second (5 mph/second). |
C0161 12
| • | Brake pedal is not applied. |
| • | Master cylinder pressure is greater than 150 psi. |
| • | The vehicle speed is greater than 24 km/h (14 mph). |
| • | The vehicles deceleration exceeds 11.5 km/h/second (7 mph/second). |
Action Taken When the DTC Sets
If equipped, the following actions occur:
| • | The EBCM disables the EDC/tire pressure monitor (TPM)/vehicle stability enhancement system (VSES) for the duration of the ignition cycle. |
| • | Traction control system (TCS) is degraded. |
| • | The Traction Control and Active Handling indicator turns ON. |
| • | The driver information center (DIC) displays the following messages: |
| - | Service Traction System |
| - | Service Active Handling |
| • | The ABS remains functional. |
Conditions for Clearing the DTC
| • | The condition for the DTC is no longer present and the DTC is cleared with a scan tool. |
| • | The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles. |
Diagnostic Aids
C0161 11
Possible causes of this DTC are the following conditions:
| • | The BPP sensor circuit is shorted to voltage. |
| • | The BPP sensor needs recalibration. |
| • | A brake pedal that is binding. |
C0161 12
Possible causes of this DTC are the following conditions:
| • | A signal circuit of the BPP sensor is open. |
| • | The BPP sensor needs recalibration. |
| • | All brake lamps are open. |
| • | All brake lamp grounds are open. |
| • | An internal BPP sensor malfunction. |
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Antilock Brake System Schematics | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
Does the scan tool display Released? | Go to Step 3 | Go to Step 4 | |
3 |
Does the BPP Reference Signal parameter change state? | Go to Diagnostic Aids | Go to Step 4 |
4 |
Did you find and correct the condition? | Go to Step 11 | Go to Step 5 |
5 |
Does the scan tool display Released? | Go to Step 8 | Go to Step 6 |
6 | Test the BPP sensor signal circuit for 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 7 |
7 | Inspect for poor connections at the harness connector of the electronic brake control module (EBCM). 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 9 |
8 | 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 11 | Go to Step 10 |
9 | Replace the EBCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 11 | -- |
10 | Replace the BPP sensor. Refer to Brake Pedal Position Sensor Replacement . Did you complete the replacement? | Go to Step 11 | -- |
11 |
Does the DTC reset? | Go to Step 2 | System OK |
