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 Descriptor

DTC B3884 00

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Stoplamp Circuit

Diagnostic Fault Information






Circuit/System Description

Battery voltage is applied at all times to the body control module (BCM) from the BCM 5 Fuse located in the underhood fuse block. When the brake pedal is applied, battery voltage is applied through the stop lamp switch and the stop lamp signal circuit to the BCM. The BCM then applies battery voltage through the stop lamp relay coil supply voltage circuit energizing the STOP LAMPS PCB Relay. With the relay energized, battery voltage is applied through the switch side of the relay and the control circuit to the auxiliary stop lamps.

Conditions for Running the DTC

* Ignition ON.

* Brakes applied.

Conditions for Setting the DTC

The BCM detects a short to ground in the stop lamp relay coil supply voltage circuit when the stop lamps are commanded ON.

Action Taken When the DTC Sets

The BCM will deactivate power to the auxiliary stop lamps.

Conditions for Clearing the DTC

* The condition responsible for setting the DTC no longer exists.

* A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Reference Information

Schematic Reference

Exterior Lights Schematics Exterior Lights Schematics

Connector End View Reference

Component Connector End Views 1-2 Shift Solenoid (SS) Valve (M30)

Description and Operation

Exterior Lighting Systems Description and Operation Exterior Lighting Systems

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 Control Module References for scan tool information

Circuit/System Verification

Ignition ON, press the brake pedal. The CHMSL should illuminate.

Circuit/System Testing

1. Ignition OFF, disconnect the X5 harness connector at the BCM.

2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 5 and ground.

• If the test lamp illuminates, test the control circuit for a short to voltage.

3. Ignition ON, connect a 3 A fused jumper wire between the control circuit terminal 5 and B+. Verify the auxiliary stop lamps illuminate.

• If the stop lamps do not illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the underhood fuse block.

4. If all circuits test normal, replace the BCM.

Repair Instructions

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

* Underhood Electrical Center or Junction Block Replacement Underhood Electrical Center or Junction Block Replacement

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