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

DTC B3890

Make
Vauxhall
Model
Astra J
Section
Diagnostic Information and Procedures › Miscellaneous › DTC B3890
Body SystemsDTC B3890

DTC B3890

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 B3890 02: Trailer Backup Lamps Circuit Short to Ground
DTC B3890 04: Trailer Backup Lamps Circuit Open

Diagnostic Fault Information



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

Trailer Backup Lamps Control
3890 02
3890 04
-
-
 

Circuit/System Description

When the transmission is placed in the reverse position, the engine control module (ECM) sends a serial data message to the body control module (BCM). The message indicates that the gear selector is in the reverse position. The BCM sends this message to the trailer lighting converter. The trailer lighting converter then applies a voltage to the trailer backup lamps through their supply circuit.

Conditions for Running the DTC

B3890 02 or B3890 04

The appropriate trailer backup lamp signal is active.

Conditions for Setting the DTC

B3890 02

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

B3890 04

The trailer lighting converter detects an open control circuit.

Conditions for Clearing the DTC

The condition for setting the DTC is no longer present.

Action Taken When the DTC Sets

The appropriate trailer backup 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 Backup Lamps test. The trailer backup lamp should be ON/OFF.

Circuit/System Testing

Trailer Backup 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 8 and ground.
3. Command the Trailer Backup Lamps 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 backup lamp circuit at the trailer.

Trailer Backup Lamp Malfunction RPO D8G

1. Ignition OFF, remove the appropriate bulb and inspect.
⇒ If bulb is faulty, replace bulb.
2. Ignition OFF, remove the harness connector of the appropriate component listed below:
  •  E5A Backup Lamp - Left
  •  E5B Backup Lamp - Right
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:
  •  E5A Backup Lamp - Left wiring color BU
  •  E5B Backup Lamp - Right wiring color GY
5. Command the Trailer Backup Lamps 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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