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

DTC B3938

Make
Vauxhall
Model
Astra J
Section
Vehicle Access › Other Information › DTC B3938
Body SystemsDTC B3938

DTC B3938

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 Descriptor

DTC B3938 02: Fuel Door Actuator Lock Circuit Short to Ground

Diagnostic Fault Information



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

Control
B3938 02
1
1
-

1. Fuel Filler Door Release Inoperative
 

Circuit/System Description

The locking and unlocking of the fuel door is a function of the power door lock system. The fuel door release actuator is supplied by the door lock signal circuit and the driver door unlock signal circuit which is switched through the fuel door relay. The fuel door relay coil is controlled by the body control module (BCM). When the vehicles doors are unlocked, the body control module (BCM) will respond by applying voltage to the fuel door relay coil control circuit. This energizes the coil causing the switch contacts to close. With the switch contacts closed, the driver door unlock circuit supplies B+ or ground to the fuel door release actuator , unlocking the fuel door.

Conditions for Running the DTC

The system voltage is 9-18 V.

Conditions for Setting the DTC

The BCM detects a short to ground on the fuel filler door relay control circuit.

Action Taken When the DTC Sets

The remote fuel filler door will be inoperative.

Conditions for Clearing the DTC

•  This DTC will be current for as long as the fault is present.
•  When the fault is no longer present, the DTC will be a history DTC.
•  A history DTC will clear after 50 ignition cycles.

Reference Information


Schematic Reference

Release Systems Schematics


Connector End View Reference

Component Connector End Views


Description and Operation

Fuel Fill Door Description and Operation


Electrical Information Reference


Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Command the door latches to LOCK and UNLOCK with a scan tool, each interior door lock knob should move between LOCK and UNLOCK
⇒ If any or all doors do not LOCK or UNLOCK, refer to Symptoms - Vehicle Access .
2. Command the door latches to LOCK and UNLOCK with a scan tool, the fuel door unlatch actuator should LOCK and UNLOCK while changing between the commanded states

Circuit/System Testing

1. Ignition OFF, disconnect the X2 harness connector at the X50A fuse block - underhood.
2. Connect a test lamp between the control circuit terminal 36 and ground.
3. Command the door latches to LOCK with a scan tool, the test lamp should briefly illuminate while commanding the LOCK state.
⇒ If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K9 body control module.
⇒ If the test lamp is always OFF, test the control circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the K9 body control module.
4. If all circuits test normal, test or replace the X50A fuse block - underhood .

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

•  Control Module References for BCM replacement, setup and programming

Parts & tools for this job For Vauxhall Astra

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