Error code B1402 is displayed and the check engine light is on - what does this mean?
The DTC B1402 is a body control module fault code that is recognized by the OBD/EOBD system and indicates a problem with the airbag warning light system. This trouble code mainly affects the airbag warning light in the dashboard and its control circuit. Depending on the vehicle manufacturer, slight variations in the code definition may occur.
What causes can this fault code have?
- Defective airbag warning light in the dashboard
- Damaged wiring to the warning light system
- Loose or corroded plug connections
- Faulty body control module (BCM)
- Blown fuse in the airbag circuit
- Defective lamp driver in the control unit
- Short circuit in the wiring
- Overvoltage damage to the warning light system
What symptoms occur in parallel with fault code B1402?
- Airbag warning light does not work: The warning light does not light up or stays on permanently
- Missing system test: No lamp test is performed when the vehicle is started
- Intermittent illumination: The warning light flickers irregularly
- Other warning lights affected: Other warning lights may not be working properly
- OBD fault code saved: Fault code B1402 is stored in the fault memory
How to fix the problem of fault code B1402?
- Repairing EOBD fault code B1402 requires a systematic approach to diagnosing and rectifying the warning light problem.
- Checking and replacing the faulty airbag warning light in the dashboard, including removing the instrument panel and installing a new light
- Checking and repairing the wiring between the body control module and the warning light, with continuity testing of all cables and replacement of damaged cable sections
- Cleaning and securing all plug connections in the warning light circuit, with contact spray treatment and firm reconnection
- Replacement of the body control module in the event of an internal defect in the lamp driver, after prior coding and programming of the new control unit
- Checking and replacing the corresponding fuse in the fuse box, followed by a functional check of the entire system
- Repair of short circuits or earth faults in the wiring by selectively replacing affected cable sections
FAQ - Frequently asked questions about DTC B1402
Can I continue driving with error code B1402?
Yes, the vehicle is basically ready to drive, but the airbag warning light is not working properly. This may result in you not being informed of any airbag system faults, which poses a safety risk.
How much does it cost to repair error code B1402?
The repair costs vary depending on the cause: bulb replacement 50-150 euros, wiring repair 100-300 euros, BCM replacement 400-800 euros. Diagnosis costs an additional 80-120 euros.
Can I repair code B1402 myself?
Simple repairs such as replacing fuses or cleaning plug connections are possible. For wiring problems or BCM replacement, you should visit a specialist workshop, as special diagnostic equipment is required.
How can I tell if the airbag warning light on B1402 is faulty?
When the ignition is switched on, the airbag warning light should light up briefly and then go out. If it remains off or lights up continuously, this indicates fault code B1402.
Does fault code B1402 disappear by itself?
No, this DTC does not disappear automatically. After the repair, the fault memory must be deleted with an OBD diagnostic device to remove the code.
Can code B1402 affect other airbag functions?
Error code B1402 primarily only affects the warning light itself. The airbag functionality is normally retained, but you will not receive any visual warnings for other airbag problems.