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For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2004 🢒 XLR 🢒 Vehicle Control Systems 🢒 Vehicle DTC Information 🢒 DTC C0161

Circuit Description

The brake pedal position sensor (BPP) is an input to the electronic brake control module (EBCM). The brake pedal position 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 in Vehicle DTC Information.

Symptom Type

Symptom Type 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 per second (5 mph per 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 per second (7 mph per second).

Action Taken When the DTC Sets

If equipped, the following actions occur:

    • The EBCM disables the EDC/TPM/VSES for the duration of the ignition cycle.
    • TCS is degraded.
    • The Traction Control and Active Handling indicator turns ON.
    • The 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 brake pedal position sensor circuit is shorted to voltage.
    • The brake pedal position 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 brake pedal position sensor is open.
    • The brake pedal position sensor needs recalibration.
    • All brake lamps are open.
    • All brake lamp grounds are open.
    • An internal brake pedal position sensor malfunction.

Test Description

The number below refers to the step number on the diagnostic table.

  1. Test for the current state of the brake pedal position sensor.

Step

Action

Yes

No

Schematic Reference: Antilock Brake System Schematics

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the BPP Reference Signal parameter in the exterior lamps data list.

Does the scan tool display Released?

Go to Step 3

Go to Step 4

3
  1. Press the brake pedal.
  2. With a scan tool, observe the BPP Reference Signal parameter.

Does the BPP Reference Signal parameter change state?

Go to Diagnostic Aids

Go to Step 4

4
  1. Turn OFF the ignition.
  2. Inspect the brake pedal position sensor and calibrate if needed. Refer to Brake Pedal Position Sensor Calibration in Lighting Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 5

5
  1. Turn OFF the ignition.
  2. Disconnect the brake pedal position sensor connector.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the BPP Reference Signal parameter.

Does the scan tool display Released?

Go to Step 8

Go to Step 6

6

Test the brake pedal position sensor signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

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 EBCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

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 brake pedal position sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 10

9

Important: Perform the setup procedure for the EBCM. An unprogrammed EBCM will result in the following conditions:

   • Inoperative or poorly functioning system operations
   • The EBCM may set DTCs

Replace the EBCM. Refer to Electronic Brake Control Module Replacement .

Did you complete the repair?

Go to Step 11

--

10

Replace the brake pedal position sensor. Refer to Brake Pedal Position Sensor Replacement in Lighting Systems.

Did you complete the repair?

Go to Step 11

--

11
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step 2

System OK