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DTC B3884

DTC B3884

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.


DTC Descriptors

DTC B3884 02

Center High Mounted Brake Lamp Circuit Short to Ground

DTC B3884 04

Center High Mounted Brake Lamp Circuit Open

Diagnostic Fault Information

Circuit Short to Ground Open/High Resistance Short to Voltage Signal Performance
Center High Mounted Brake Lamp Control B3884 02 B3884 04 1 B0655 5A
Center High Mounted Brake Lamp Ground - B3884 04 - -
1. Center High Mounted Brake Lamp Always ON


Circuit/System Description

The brake pedal position sensor is used to sense the action of the driver application of the brake pedal. The brake pedal position sensor provides an analog voltage signal to the body control module (BCM). The BCM will apply battery voltage to the right, left and center stop lamp control circuits.

Conditions for Running the DTC

The brakes are applied.

Conditions for Setting the DTC

B3884 02

The BCM detects a short to ground on the center high mounted brake lamp control circuit

B3884 04

The BCM detects an open/high resistance on the center high mounted brake lamp control circuit

Action Taken When the DTC Sets

The center high mounted brake lamp will not illuminate.

Conditions for Clearing the DTC


• The DTC will be current for as long as the fault is present.

• When the fault is no longer present, the DTC will be a history DTC.

• A history DTC will clear after 50 ignition cycles.


Reference Information

Schematic Reference

Exterior Lights Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lights Schematics

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

Ignition ON, command the E6 center high mounted stop lamp ON and OFF by applying and releasing the brake pedal. The E6 center high mounted stop lamp should turn ON and OFF each time the brake pedal is applied and released.

Circuit/System Testing


1. Ignition OFF, disconnect the harness connector at the E6 center high mounted stop lamp.

2. Test for less than 30 Ω between the ground circuit terminal B and ground.

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

4. Connect a test lamp between the control circuit terminal A and ground.

5. Ignition ON, command the center high mounted stop lamp ON and OFF by applying and releasing the brake pedal. The test lamp should turn ON and OFF when changing between the selected states.

6. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K9 BCM.

7. 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 BCM.

8. If all circuits test normal, replace the E6 center high mounted stop lamp.


Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.


• High Mount Stop Lamp Replacement

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