9 Causes Airbag Light On in Your Car

Last Updated on November 25, 2019 by themechanic

Airbags can save your life if you’re ever in an accident. It is important that you have functional airbags for this reason. You don’t want to find out the hard way that your airbags are not working because it could result in serious injury or death if an accident occurs. Fortunately, modern cars have an airbag warning light built into the dashboard. This airbag light will activate whenever a problem is detected with the airbag system. It won’t indicate exactly what the problem with the airbag is, but it will be enough for you to have the problem investigated by a mechanic.

The airbag light normally turns on after you start your engine. But as soon as you put on your seatbelt, the light deactivates. If you notice the airbag light staying on, then it means your airbags are faulty in some way. Sometimes the seatbelt light may be shared with the airbag light, meaning that either your seatbelt or airbag is the problem when the light is on. That is why putting on the seatbelt should deactivate the light. If it doesn’t, then it is your airbag at fault.

Common Causes Airbag Light on

Do not ignore the illumination of the airbag light. You may think to yourself that it’s no big deal because you assume that you won’t get into an accident. But there is always the chance that you could get into an accident, so why risk it? Have your airbag system checked by a licensed mechanic before it is too late.

Below are the top 9 causes of the airbag light coming on in your car. One of these will likely be the reason for your illuminating airbag light.

1. Seatbelt Not On

In many cases, the airbag light may be on simply because your seatbelt is not on. This only applies to the driver’s seatbelt since the car cannot detect if anyone else is sitting down in the cabin. There may also be a problem where seatbelt buckle doesn’t click properly, so make sure that you hear the click. Otherwise, that may keep the airbag light on as well.

2. Deactivated Airbag

You may have a functional airbag that is just deactivated in the system. The airbag needs to be activated before it will work for you in an accident situation. You may wonder, why would the airbag be deactivated? Well, it could be due to a crash sensor glitch or an error that the mechanic made when they were working on your vehicle.

3. Airbag Backup Battery is Low

The airbag system has a backup battery which relies on the primary car battery for its power. This backup battery may lose power if the primary battery is low on power too. This can also happen if you’ve just been in an accident as well. Whatever the reason, a low backup battery in the airbag system will cause the airbag light to turn on.

4. Corroded / Failure Crash Sensors

If water were to get onto your crash sensors, they will start to corrode very quickly. Any type of water damage to your vehicle can cause this to happen. Your airbag system is very sensitive when it comes to its crash sensors. Water damage will distort their functionality and cause the airbag light to illuminate.

5. Post-Accident

Not all car accidents are big catastrophes which cause airbags to be deployed. Sometimes you may get into a small accident or vender bender which isn’t serious enough to deploy the airbags. However, it is still serious enough to activate the crash sensors. This means your airbag light will illuminate until you get the sensors reset again.

6. Minor Accident

The airbag system is comprised of sensors and a computer. The system will normally deploy your airbags if you crash your vehicle into something at a minimum of 8 miles per hour. However, there may be times when you crash into something as you’re driving less than 8 miles per hour. Perhaps you pull up too close to your garage door in the driveway or accidentally bump into your mailbox. Whatever the case, a small accident like this that seems insignificant could still trigger the computer to illuminate the airbag light. It might be confused and think the airbag already deployed even though it didn’t.

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7. Failure Airbag ECU

The airbag electronic control unit is responsible for deploying the airbag when there is an accident. There are separate crash sensors which send information about the impact to the airbag ECU. This information includes the type of collision and the seriousness of it. If the ECU determines that the crash is worthy of airbag deployment, then it will activate the airbags. If the ECU is malfunctioning, however, then the airbag light will come on.

8. Failure Pretensioner Seatbelt

A pretensioner seatbelt is the type of seatbelt which automatically locks the belt down if there is an accident. That way, you won’t be able to get pushed forward by the intensity of the crash. This pretensioner is technically part of the airbag system. That is why if there is a malfunction in the pretensioner seatbelt, the airbag light will come on. All components of the airbag system must remain functional, even indirect ones like this.

9. Failure Spiral Cable

Spiral cable attach in steering wheel and connected to horn pad and driver airbag system. If the spiral cable failure, the air bag will come on. Common symptom of spiral cable failure is: the horn not working when you push horn pad.

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