Workshop Manuals Factory service & repair Vauxhall
Vauxhall Astra J05 · Body Systems
05 · Body & interior

DTC B3891

Make
Vauxhall
Model
Astra J
Section
Lighting › Other Information › DTC B3891
Body SystemsDTC B3891

DTC B3891

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 B3891 02: Trailer Fog Lamps Circuit Short to Ground
DTC B3891 04: Trailer Fog Lamps Circuit Open

Diagnostic Fault Information



Circuit
Short to Ground
Open/High Resistance
Short to Voltage
Signal Performance

Trailer Fog Lamps Control
3891 02
3891 04
-
-
 

Circuit/System Description

The front fog lamp switch signal circuit is grounded momentarily by pressing the front fog lamp switch. The body control module (BCM) sends this message to the trailer lighting converter. The trailer lighting converter applies voltage to the trailer fog lamps through their supply circuit.

Conditions for Running the DTC

B3891 02 or B3891 04

The appropriate trailer fog lamps signal is active

Conditions for Setting the DTC

B3891 02

The trailer lighting converter detects a short to ground on the control circuit.

B3891 04

The trailer lighting converter detects an open control circuit.

Conditions for Clearing the DTC

The condition for setting the DTC is not longer present.

Action Taken When the DTC Sets

The appropriate trailer fog lamp is inoperative.

Reference Information


Schematic Reference

Trailer Connector/Provision Schematics


Connector End View Reference

Component Connector End Views


Description and Operation

Exterior Lighting Systems Description and Operation


Electrical Information Reference


Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Ignition ON, perform the Trailer Fog Lamp(s) test. The trailer fog lamps should be ON/OFF

Circuit/System Testing

Trailer Fog Lamp Malfunction RPO VQ9

1. Ignition OFF, test for less than 5 Ω between the X88 Trailer Connector terminal 3, 11, 13 and ground.
⇒ If greater than the specified value, test the appropriate ground circuit for an open/high resistance.
2. Connect a test lamp between the X88 Trailer Connector terminal 2 and ground.
3. Command the Trailer Fog Lamp(s) test with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
⇒ If the test lamp is always ON, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K68 Trailer Lighting Control Module.
⇒ If the test lamp is always OFF, test the signal circuit for a short to ground or an open/high resistance. If the circuits test normal, replace the K68 Trailer Lighting Control Module.
4. If all the circuits test normal, test the fog lamps circuit at the trailer.

Trailer Fog Lamp Malfunction RPO D8G

1. Ignition OFF, remove the appropriate bulb and inspect.
⇒ If bulb is faulty, replace bulb.
2. Ignition OFF, remove the bulb of the appropriate component listed below:
  •  E29LR Fog Lamp - Left Rear
  •  E29RR Fog Lamp - Right Rear
3. Test for less than 5 Ω between the ground circuit harness connector wiring color WH and ground.
⇒ If greater than the specified value, test the appropriate ground circuit for an open/high resistance.
4. Connect a test lamp between the appropriate control circuit terminal listed below and ground:
  •  E29LR Fog Lamp - Left Rear wiring color dark BU
  •  E29RR Fog Lamp - Right Rear wiring color GY
5. Command the Trailer Fog Lamp(s) test with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
⇒ If the test lamp is always ON, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K68 Trailer Lighting Control Module.
⇒ If the test lamp is always OFF, test the signal circuit for a short to ground or an open/high resistance. If the circuits test normal, replace the K68 Trailer Lighting Control Module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for trailer lighting converter replacement, setup, and programming

Parts & tools for this job For Vauxhall Astra

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