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Stop Lamps Malfunction

Stop 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 has overviews of all diagnostic categories.


Diagnostic Fault Information

Circuit Short to Ground Open/High Resistance Short to Voltage Signal Performance
5V Reference

C0277 06

C0277 06

C0277 07

-

Signal

C0277 06

C0277 06

C0277 07

C0277 09

Left Brake Lamps Control

1

1

2

-

Right Brake Lamp Control

1

1

2

-

Low Reference

-

1

-

-

1. Stop lamps malfunction

2. Stop lamps always ON



Circuit/System Description

The brake pedal position (BPP) sensor is used to sense the action of the driver application of the brake pedal. The brake pedal position (BPP) sensor provides an analog 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 brake pedal position sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the BCM will apply battery voltage to the stop lamp control circuit and center high mounted stop lamp control circuit. When the control circuit is energized the stop lamps are illuminated.

Reference Information

Schematic Reference

Exterior Lights 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 information on diagnostic tools

Circuit/System Verification


1. Ignition ON, observe the scan tool Brake Switch parameter. The reading should be between Inactive/Active and change when the brake pedal is pushed or released.

2. If the reading did not change between Inactive/Active, refer to Brake Pedal Position Sensor Malfunction.

3. Ignition ON, perform the Brake Lamp Command test. The brake lamps should be ON/OFF.

4. If the brake lamps did not turn ON and OFF, refer to Brake Lamp Malfunction.


Circuit/System Testing


Brake Pedal Position Sensor Malfunction

1. Ignition OFF, disconnect the harness connector at the B22 Brake Pedal Position Sensor.

2. Ignition OFF, test for less than 5 Ω between the low reference circuit terminal C and ground.

3. If greater than the specified range, test the low reference circuit for an open/high resistance.

4. If the circuit tests normal, replace the K9 Body Control Module.



Brake Lamp Malfunction

1. Ignition OFF, disconnect the appropriate harness connector at the tail lamp listed below:

• E5E Tail Lamp - Left

• E5F Tail Lamp - Right

2. Test for less than 5 Ω between the appropriate ground circuit harness connector terminal listed below and ground:

• E5E Tail Lamp - Left harness connector terminal F

• E5F Tail Lamp - Right harness connector terminal F

• If greater than the specified value, test the appropriate ground circuit for an open circuit/high resistance.

3. Connect a test lamp between the appropriate control circuit harness connector terminal listed below and ground:

• E5E Tail Lamp - Left harness connector terminal C

• E5F Tail Lamp - Right harness connector terminal C

4. Apply the brake pedal. The test lamp should turn ON and OFF when changing between applied and not applied.

5. If the test lamp is always ON, test the appropriate control circuit for a short to voltage. If the circuit tests normal, replace the K9 Body Control Module.

6. If the test lamp is always OFF, test the appropriate control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module.

7. If all circuits test normal, test or replace the appropriate tail lamp.


Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.


• Control Module References for information on BCM replacement, setup, and programming

• Tail Lamp Replacement