Airbag Warning Light Won't Turn Off: What to Do?
Airbag warning light won't turn off: What to do?
If the airbag warning light stays on continuously after starting the engine, there is a malfunction in the SRS system. The restraint system – airbags and seat belt tensioners – may then be deactivated and would not deploy in an accident. The cause must be determined by diagnosis and corrected before the light goes out.
Normally, the airbag warning light illuminates for a few seconds after turning on the ignition and then goes out again. This brief self-test indicates that the system is functioning. If the light remains on continuously, blinks, or suddenly illuminates while driving, the control unit stores an error code that points to the problem.
Common causes of a continuously illuminated airbag warning light
The most common causes are defective connectors under the front seats, a worn spiral cable in the steering wheel, a defective seat occupancy mat on the passenger side, or a voltage drop due to a weak battery. Stored crash data after an accident can also keep the light permanently active.
| Cause | Frequency | Typical symptoms |
|---|---|---|
| Connector under the seat | Very common | Light turns on/off when moving seat |
| Spiral cable (Clock Spring) | Common | Light + horn/steering wheel buttons don't work |
| Seat occupancy mat defective | Common | Passenger airbag disabled, light on |
| Weak battery / voltage drop | Common | Light after jump start or battery replacement |
| Crash data in control unit | After accident | Light stays on permanently after collision |
| Seat belt buckle contact dirty | Occasionally | Light + seat belt warning doesn't work correctly |
| Crash sensor defective | Rare | Error code shows specific sensor |
| Control unit defect (internal) | Rare | Multiple error codes simultaneously, not erasable |
Connectors as the most common cause
The yellow or orange connectors under the front seats are critical points in the SRS system. They carry signals for side airbags, seat belt tensioners, seat belt buckle switches, and seat occupancy detection. Even micro-interruptions from loose contacts, moisture ingress, or corrosion on the pins can trigger the fault. In vehicles with adjustable seats, these connectors are stressed with every seat adjustment.
Spiral cable in the steering wheel
The spiral cable (also called spiral cable or clock spring) provides the electrical connection between the stationary dashboard and the rotating steering wheel. It supplies power to the driver airbag, horn, and steering wheel buttons. Due to wear from every steering movement, the spiral cable can break after years. Note: Even if the horn still works, the spiral cable can still be defective – the airbag line can be interrupted separately.
What does the airbag light mean for safety?
When the airbag warning light is continuously illuminated, the control unit has deactivated the restraint system in whole or in part. In the event of an accident, airbags and seat belt tensioners may not deploy. The vehicle is roadworthy, but occupant protection is significantly reduced.
| Situation | Meaning | Recommendation |
|---|---|---|
| Light on briefly, then off | Normal self-test – system OK | No action needed |
| Light on continuously | Error stored, system possibly off | Visit workshop soon |
| Light blinks | Active error, system deactivated | Perform diagnosis immediately |
| Light doesn't come on at all | Warning lamp defective or tampered with | Check immediately – TÜV-relevant |
Can you drive with the airbag light on?
Basically, the vehicle is roadworthy and there is no legal driving ban. However, occupant protection is limited and at the next main inspection (TÜV), the sticker will be refused if the airbag warning light is continuously illuminated. In the event of an accident, liability issues can also arise.
- Continue driving: Technically possible, but with reduced safety level
- TÜV/inspection: Continuously illuminated airbag light = significant defect, no sticker
- Insurance: In case of personal injury, reductions may threaten if the SRS was demonstrably defective
- Recommendation: Have the cause determined and corrected soon
Diagnosis: How the cause is found
The exact cause of the fault is determined by reading the error memory in the airbag control unit. This requires a diagnostic device with access to the SRS system – simple OBD-2 adapters are not sufficient. The error code read shows exactly which component or circuit is affected.
- Connect diagnostic device: Connect OBD-2 port (usually in driver's footwell) with SRS-capable device
- Read error memory: Select SRS control unit and read stored codes
- Analyze error code: Code provides information about affected component and fault type
- Visual inspection: Visually check connectors, cables, and affected components
- Repair/replace component: Repair or replace defective component
- Clear error memory: After repair, delete error code with diagnostic device
- Check: Turn ignition off/on – light must go out after self-test
Important: The warning light usually does not go out on its own, even if the cause has been corrected. The error code must be actively deleted from the control unit's memory.
What can I check myself?
Without a diagnostic device, options are limited. You can check the connectors under the front seats for secure fit and measure battery voltage. Work on the airbag system itself – such as on the steering wheel or side airbags – may only be performed by trained professionals.
| Can check yourself | Professional workshop only |
|---|---|
| Check connectors under seat for secure fit | Replace spiral cable in steering wheel |
| Measure battery voltage | Replace seat occupancy mat |
| Visual inspection for obvious cable damage | Replace crash sensors |
| Read error memory with own diagnostic device | Repair or reprogram control unit |
| Check seat belt buckle for dirt | Delete crash data in EEPROM |
Repair costs for illuminated airbag light
Costs vary greatly depending on the cause – from simple connector correction to control unit repair. Exact prices for replacement parts such as spiral cables, seat occupancy mats, or crash sensors can be found in our shop. Airbag24 offers professional repairs for all brands – TÜV-safe and significantly cheaper than the authorized dealer.
| Repair | What is done? | Solution |
|---|---|---|
| Connector repair | Clean contacts, replace connector | Workshop or specialist |
| Replace spiral cable | Remove steering wheel, renew spiral cable | Workshop (observe explosives law) |
| Seat occupancy mat | Open seat cushion, replace mat | Specialist like Airbag24 |
| Delete crash data | EEPROM programming in control unit | Specialist only (Airbag24) |
| Control unit repair | Replace defective components, reprogram | Specialist like Airbag24 |
Frequently asked questions about the airbag warning light
Here you will find answers to the most important questions about the continuously illuminated airbag warning light.
Can I clear the airbag light by disconnecting the battery?
No. Airbag error codes are stored in the non-volatile EEPROM memory of the control unit and remain even without power supply. Disconnecting the battery has no effect on stored SRS error codes – a diagnostic device with SRS access is required to clear them.
Why does the airbag light come on after a battery replacement?
When replacing the battery, the on-board voltage drops briefly. The airbag control unit registers this voltage drop as an error and stores an under-voltage code. In most cases, this error code must be cleared with a diagnostic device, after which the light goes out.
Is it allowed to disable the warning light?
No. Tampering with, bypassing, or removing the airbag warning light is not permitted and poses a significant safety risk. Additionally, it is TÜV-relevant: the warning light must briefly illuminate during the self-test and then go out. If it is missing entirely, this will also be flagged.
When should I go to the workshop immediately?
You should act immediately if the light comes on after an accident or impact, if it suddenly illuminates while driving, or if other warning lights are active at the same time. In these cases, there may be a serious defect in the restraint system that poses an immediate safety risk.