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Brake Lamps Malfunction

Diagnostic Instructions
    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    • Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

F10DL Fuse B+

C0890 03, B101E 43, B1395 03, B1517 07, U0121 00, U0128 00, U0422 71

C0890 03, B101E 43, B1395 03, B1517 07, U0121 00, U0128 00, U0422 71

--

--

Brake Pedal Position Sensor 5V Reference

C0277 06, C0890 03, U0422 71, C0561 71

C0277 06, U0422 71, C0561 71

C0277 07, C0890 07, U0422 71, C0561 71

-

Brake Pedal Position Sensor Signal

C0277 06, U0422 71, C0561 71

C0277 06, U0422 71, C0561 71

C0277 07, C0890 07, U0422 71, C0561 71

C0277 09

Centre High Mounted Brake Lamp Control

2

2

2

--

Brake/Indicator Lamp Control - Left

1

1

1

--

Brake/Indicator Lamp Control - Right

1

1

1

--

Brake Pedal Position Sensor Low Reference

-

C0277 06, U0422 71, C0561 71

1

--

Centre High Mounted Brake Lamp Ground

--

2

--

--

Tail/Brake Lamp Ground - Left

--

1

--

--

Tail/Brake Lamp Ground - Right

--

1

--

--

1. Brake Lamps Malfunction

2. Centre High Mounted Brake Lamp Malfunction

Circuit/System Description

The brake pedal position (BPP) sensor is used to sense the action of the driver application of the brake pedal. The BPP sensor provides an analogue voltage signal that will increase as the brake pedal is applied. The body control module (BCM) provides a low reference signal and a 5 V reference voltage to the BPP sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the BCM will apply battery voltage to the left and right brake lamp control circuits as well as the centre high mounted brake lamp control circuit illuminating the left and right brake lamps and the centre high mounted brake lamp.

Reference Information

Schematic Reference

    •  Exterior Lamps Schematics
    •  Body Control System Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification
  1. Vehicle in Service Mode, observe the scan tool Brake Pedal Applied parameter while pressing and releasing the brake pedal. The parameter should change between Active and Inactive as the brake pedal is applied and released.
    2. ⇒If the parameter does not change between the commanded states, refer to the Brake Pedal Position Sensor Malfunction.
  2. Command the Left Rear Indicator/Brake Lamp ON and OFF with a scan tool. The left brake lamp should turn ON and OFF when changing between the commanded states.
    3. ⇒If the left brake lamp does not turn ON and OFF when changing between the commanded states, refer to Brake Lamps Malfunction.
  3. Command the Right Rear Indicator/Brake Lamp ON and OFF with a scan tool. The right brake lamp should turn ON and OFF when changing between the commanded states.
    4. ⇒If the right brake lamp does not turn ON and OFF when changing between the commanded states, refer to Brake Lamps Malfunction.
  4. Command the Centre Brake Lamp ON and OFF with a scan tool. The centre high mounted brake lamp should turn ON and OFF when changing between the commanded states.
    5. ⇒If the centre high mount brake lamp does not turn ON and OFF when changing between the commanded states, refer to Centre High Mount Brake Lamp Malfunction.

Circuit/System Testing

Brake Pedal Position Sensor Malfunction

  1. Vehicle OFF, disconnect the harness connector at the B22 Brake Pedal Position Sensor.
  2. Vehicle in Service Mode, verify that a test lamp does not illuminate between the low reference circuit terminal C and ground.
    3. ⇒If the test lamp illuminates, test the low reference circuit for a short to voltage. If the circuit tests normal, replace the K9 Body Control Module.
  3. If all circuits test normal, replace the B22 Brake Pedal Position Sensor.

Brake Lamps Malfunction

  1. Vehicle OFF, disconnect the harness connector at the inoperative tail lamp assembly.
  2. Vehicle OFF, exterior lamps OFF, test for less than 5 Ω between the ground circuit terminal 4 and ground.
    3. ⇒If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Connect a test lamp between the control circuit terminal 1 and ground.
  4. Vehicle in Service Mode, command the appropriate Rear Indicator/Brake Lamp ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
    5. ⇒ If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K9 Body Control Module.
    ⇒ If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module.
  5. If all circuits test normal, replace the inoperative tail lamp assembly.

Centre High Mount Brake Lamp Malfunction

  1. Vehicle OFF, disconnect the harness connector at the E6 Centre High Mounted Brake Lamp.
  2. Vehicle OFF, exterior lamps OFF, test for less than 5 Ω between the ground circuit terminal 2 and ground.
    3. ⇒If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Connect a test lamp between the control circuit terminal 1 and ground.
  4. Vehicle in Service Mode, command the Centre Brake Lamp ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
    5. ⇒ If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K9 Body Control Module.
    ⇒ If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module.
  5. If all circuits test normal, replace the E6 Centre High Mounted Brake Lamp.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Tail Lamp Replacement
    •  High Mount Brake Lamp Replacement
    • Control Module References for BCM replacement, programming and setup
   


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