Drive as if the airbags won't work
This isn't a pull-over-now light unless it comes with smoke or a burning smell, so find somewhere safe and switch off if it does. Otherwise it's a get-it-checked-now light. Wear your seatbelt, leave more room, and keep trips short until it's read. Don't unplug anything under the seats or behind the steering wheel to try to fix it: airbags are set off by an explosive charge and can fire during the wrong work. If you've just had a crash and anyone is hurt or in danger, call 000.
What should the light normally do?
It should come on briefly when you start the car, then go out. That's the system checking itself. Genesis's Australian owner's manual gives about three to six seconds, and other makes will be close, but go by your own manual. It also lists what counts as a fault, and that list is a good test for any car.
Signs the system has a fault
- The light doesn't come on at all when you start the car.
- It stays on after those first few seconds.
- It comes on while you're driving.
- It blinks while the engine's running.
- It's on and the steering wheel buttons have stopped working.
Why does it matter if the car drives fine?
Because you won't find out until you need it. CAA-Quebec, the Canadian motoring club, lists the risks: airbags that don't deploy in a collision, airbags that deploy unexpectedly, and seatbelts that lose their tension support. Genesis's manual warns that a fault can raise the risk of serious injury or death.
The light can't tell you which part is at fault or how serious it is. Only the stored code can.
What usually causes it?
- The clock spring: the coiled ribbon that keeps the driver's airbag and wheel buttons connected as the wheel turns. RACV says if the light's on and the steering wheel controls stop working, it likely needs replacing without delay.
- Seatbelt pretensioners: the devices that pull the belt tight in a crash. They're on the same system as the airbags.
- Seat sensors: Auto Express lists the occupant classification system, which tells the car if someone's in the seat.
- Wiring under the seats: plugs can be knocked by moving the seats or by things stored under them.
- A low battery: a flat battery or a jump start can leave a fault stored.
- An earlier crash or water damage: a past repair that didn't deal with everything, or damp reaching the connectors.
Is the airbag off light the same thing?
No. NRMA's list of dash symbols counts airbag warning and airbag deactivated as separate lights. On cars with a passenger airbag switch or a seat sensor, the deactivated symbol can simply be showing what the system is set to. Check the owner's manual, and if the passenger airbag shows off with an adult in the seat, have it looked at.
What will the mechanic do?
They'll connect a scan tool that can read the airbag computer, often called the SRS (supplemental restraint system) module. A basic engine code reader usually can't see it. The code names a circuit, such as the driver's airbag or a seat sensor.
A good mechanic tests that circuit before replacing anything, and follows the maker's steps for making the system safe first. Then they clear the code and check the light does what it should: on for a few seconds, then out. If it comes back, the fault's still there.
This suits a mechanic or auto electrician who has a scan tool for your make. See diagnostics. Independents can buy the same repair information as dealers for cars made from 2002 on, so ask whether they have it for your car.
What to ask before you say yes
- Which code did you find, and which part does it point to?
- What did you test to confirm it?
- Is a seatbelt pretensioner involved?
- Has the light stayed off after a restart?
- Does anything suggest a past crash or repair?
Buying a used car?
Watch the dash as you turn the key. If the airbag light doesn't come on at all, that's a fault too, and worth raising before you pay. A pre-purchase inspection can cover it. The light also doesn't tell you whether a car has an open recall, so ask the maker about that separately.
What you can do, and what has to stay with the mechanic
You can
- Watch what the light does when you start the car.
- Check nothing is jammed under the front seats, leaving the wiring alone.
- Check the seatbelts buckle and retract properly.
- Note what happened first: a flat battery, a spill, seat work or a bump.
Leave to the mechanic
- Reading the airbag computer.
- Testing or replacing the clock spring, sensors, wiring or pretensioners.
- Making the system safe before working on it.
- Clearing the code once the fault is fixed.
If it were us
We'd have the code read this week, and we wouldn't let anyone clear it without finding the cause. You can usually still drive to the mechanic, so there's no need for a tow unless something else is wrong. If the car carries kids or does long highway trips, we'd move it to the top of the list. It's often a small fault, and it's good to know the system is working again.