Airbag light on: the real risk, the causes, and inspections
Updated · Autofy
Airbag light on: the real risk, the causes, and inspections
An airbag light that stays on means the control unit has found a fault in the passive safety system: the airbags, and sometimes the seatbelt pretensioners, may not deploy in a crash. The car drives normally, but protection is no longer guaranteed. The most common causes are a connector under a seat, the steering wheel clockspring or a weak battery. An airbag light left on fails the French contrôle technique as a major defect, and fails the UK MOT too.
What this light monitors
The light shows a seated passenger with a balloon in front. It's driven by the airbag control unit, which constantly checks the front and side airbags, curtains, seatbelt pretensioners and crash sensors.
With the ignition on, it lights up for a few seconds then goes out: that's the self-test. If it stays on or flashes, the unit has found a fault and may disable all or part of the system.
The real risk
The car drives normally and nothing feels different behind the wheel. That's exactly why this light is easy to ignore. But in a crash, one or more airbags may not deploy, and the pretensioners may not hold occupants in place. It's a safety fault, not a comfort one.
Most common causes
- A connector under a front seat. Seat moved forward, back or removed, a mat jammed, a vacuum cleaner pushed too close: the side airbag or pretensioner connector works loose or corrodes.
- The steering wheel clockspring, which links the driver's airbag to the rest of the car. It wears with steering. Common sign: the horn or wheel buttons stop working at the same time.
- A weak battery, or one disconnected recently, leaving a stored fault.
- A crash sensor or the control unit, more rarely.
- An airbag that has already deployed and wasn't replaced, on a previously crashed car.
Only a diagnostic scan reads the code and identifies the faulty part. Never unplug an airbag connector yourself with the ignition on: an accidental deployment can injure you.
Airbag light and inspections
In France, an airbag light that stays on is a major defect: the test fails and a re-test is required after repair.
Since 1 January 2026, vehicles fitted with Takata airbags under an outstanding stop-drive recall fail for a critical defect. The details are in our inspection guide. If your car is affected, the replacement is free at the manufacturer.
Don't forget it until the inspection
A light that doesn't change how the car drives tends to be forgotten, until inspection day. Autofy keeps the fault in your list, ranked by severity (passive safety sits near the top), and factors it into your car's health score until it's fixed. Every other light is in our dashboard warning lights guide.