B3882

DTC B3881 or B3882

Diagnostic Instructions

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

DTC Descriptors
DTC B3881 02
- Tail Lamp Circuit Short to Ground

DTC B3881 04
- Tail Lamp Circuit Open

DTC B3882 02
- Right Tail Lamp Circuit Short to Ground

DTC B3882 04
- Right Tail Lamp Circuit Open

Diagnostic Fault Information





Circuit/System Description

The headlamp switch is supplied with ground at all times. When the headlamp switch is placed in either the park or low beam position, ground is applied through the tail lamp signal circuit to the body control module (BCM). The BCM responds by applying battery voltage to the left and to the right tail lamp control circuits. This energizes the tail lamps, side marker lamps, position lamps, park/turn signal lamps.

Conditions for Running the DTC

The headlamp switch is in park or low beam position.

Conditions for Setting the DTC

B3881 02 or B3882 02

The BCM detects a short to ground on the appropriate tail lamp control circuit.

B3881 04 or B3882 04

The BCM detects an open circuit on the appropriate tail lamp control circuit.

Action Taken When the DTC Sets

The appropriate tail lamp is inoperative.

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 Lighting Systems Description and Operation (Exterior Lighting Systems Description and Operation)
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, turn the headlamp switch between the PARK and OFF positions. The tail lamps should turn ON and OFF when changing between the selected states.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the E42 tail lamp assembly.
2. Test for less than 5 ohm between the ground circuit terminal C 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 B and ground.
4. Turn the tail lamps ON and OFF using the headlamp switch. 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, test or replace the E42 tail lamp assembly.

Repair Instructions

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

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