B3884

DTC B3884

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (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/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 and to the trailer lighting converter if installed in the vehicle.

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 circuit on the center high mounted brake lamp control circuit.

Action Taken When the DTC Sets

Brake lamp does not illuminate.

Conditions for Clearing the DTC

The condition for setting the DTC is no longer present.

Reference Information
Schematic Reference

Exterior Lights Schematics (Exterior Lights Schematics)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Exterior Lights Schematics (Exterior Lights Schematics)
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing For Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Verification

Ignition ON, observe the center high mounted brake lamp while pressing and releasing the brake pedal. The center high mounted brake lamp should turn ON and OFF when changing between the selected states.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the E6 center high mounted stop lamp.
2. Test for less than 5 ohm between the ground circuit terminal 1 and ground.

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

3. Connect a test lamp between the control circuit terminal 2 and ground.
4. Turn the center high mounted brake 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.

• 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.
• 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.

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

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* High Mount Stop Lamp Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for BCM replacement, setup and programming