Airbags are an important safety measure in case of an accident. But if they go off when you don’t need them to, that might hurt. So, as a precaution, many of us disconnect the battery if it’s needed to work on them.
But still, can airbag go off with battery disconnected?
Yes, the airbags will go off even if you disconnect the battery. That’s because they have a backup power supply. But some cars’ airbag systems might not have backup power stored. In that case, the airbags will not go off after disconnecting the battery. Even then, you need to discharge the residual energy first.
That being said, how do the airbags actually work? Can they accidentally deploy and hurt you?
We will be talking about all that in the next few sections. So, you might want to check that out.
Understanding The Power Requirement of Airbag System
First, let’s get to know how the airbags work.
Take a look at the simple airbag circuit diagram. There are three sensors: two primary crash sensors and one safing sensor. All these sensors must trigger in order to deploy the airbags.
In the event of a crash, these sensors send a signal to inflate the airbags. The collision force must be at least 16 mph. The airbags get power from the battery, which ignites NaN3 and KNO3. These two gases react and produce nitrogen, which then inflates the airbag.
So, as you can see from the circuit, airbags have two power supplies. In normal cases, it gets its power from the main 12-volt battery. When it is dead or disconnected, it will get power from the backup power supply, which is usually a large capacitor.
Can Airbag Go Off With Battery Disconnected?
The answer is yes and no at the same time. This depends on the airbag system of your car. There are two possible cases. We must consider both of them for an exact answer.
Yes, In Case The Airbag System Doesn’t Have A Capacitor
Some airbag systems only have one power source operating them, which is the main 12-volt battery. So, disconnecting it will disable the SRS (Supplementary Restraint System), which does not have backup power.
However, there might be some residual power left in the system. That might trigger the airbags too. So, it’s best to wait some time after disconnecting the battery if you want to remove the airbags.
Make sure you always maintain safety protocols. That’s because car batteries may shock you if you’re not careful.
It’s better to wait for at least 5 minutes for the residual electricity to die down. Or, if you don’t want to wait that long, turn on the AC or other electronic components so that the power depletes faster.
No, In Case The Airbag System Has A Capacitor
Disconnecting the battery will not be enough in some cars, as the SRS has a backup power system. If you disconnect the main battery, the airbag system will get its power from the backup capacitor. That means they can still deploy, and it’s not safe for you to work on it.
Most modern-day vehicles have this safety feature. This ensures safety for the driver and the passenger even if the battery is somehow disabled in a crash.
But that doesn’t mean it’s impossible to disable the airbags in those cars. You just have to disconnect a few extra parts. We will be going over that shortly.
Although disconnecting the battery might reset your airbags, in that case you should go get help from a mechanic. That’s because resetting the airbag might complicate things.
Do Airbags Deploy If The Car Is Off?
Yes, the airbags have a chance to deploy even if the engine is off, as long as the ignition is on. That’s because ignition powers the vehicle’s electrical system, so all the electronic devices in your car will be up and running. That includes the airbags.
The airbags should not go off if the ignition is off. But in some cases, they might still go off for a short time if there is residual energy within the system. The residual energy will be there for a minute to an hour after you turn the ignition off.
That is actually a good feature if you take your safety into account. Accidents can happen at any time. Another car might bump into yours when you are stuck in traffic or even parking your car.
This is why you have to be extra careful when working on your steering wheel or the airbag system. Accidental airbag deployment doesn’t happen that often. But if it does, it will hurt you. That’s because to match the impact of the accident, the airbags deploy at a high speed.
The usual deployment speed of an airbag is 100–200 mph, which is faster than the blink of an eye. If that hits your face, the least it will do is break your nose.
Can Airbags Be Turned Off?
Yes, for sure. But not all cars have this feature. This feature is installed only to turn off the passenger airbag.
You must read your car’s instruction manual to find out if you have this function. This feature is often called PACOS, or the passenger airbag cutoff system. If your car doesn’t have this installed, your passenger airbag cannot be turned off unless you do it manually.
Typically, the PACOS is found on the passenger side of the dashboard. The switch will only have the “on” and “off” positions. You will need a unique key that you will have to enter into the switch.
Then turn the switch from “on” to “off.” If you manage to successfully deactivate the passenger airbag, a light on your dashboard will confirm it.
Some modern cars have an automatic disabling system that turns off the passenger airbag. For instance, if the passenger seat is empty, the vehicle will automatically turn off the passenger airbag.
But it’s not recommended to turn off the passenger airbag. Unless there is a child in it with a rear-facing child seat. It is against the law to travel with a child seat with the passenger airbag activated.
Can An Airbag Be Removed Without Disconnecting The Battery?
Yes, sure, you can remove an airbag with the battery still connected. But it is very dangerous. It will be like carrying a chainsaw that is still on and running.
It is not recommended to try to remove an airbag while the battery is still connected. Even disconnecting the battery does not deactivate the airbags, so the risk of the airbags popping up is very high.
Airbags go off faster than a blink of an eye—nearly 200 miles per hour. If you try to remove the airbags without following the proper procedure, they might pop. That will happen so fast, you won’t even know what just happened.
You would suffer significant injuries if something similar occurred. You may only sustain a broken nose if you’re lucky. But in the worst-case scenario, you might get your neck broken.
So, do not even think of removing the airbags with the battery attached. Follow the proper procedure, which we have mentioned below.
- Disconnect the battery.
- Take out the airbag fuse. You can use an OBD scanner to check
- Open up the dashboard.
- Disable the passenger seat airbag.
- Take out the lower panel of the steering wheel
- Disable the driver seat airbag.
We have explained the process in a concise way. How to deactivate airbags is explained in detail here.
Can you survive a car crash without an airbag?
Without an airbag, your odds of surviving a car accident are almost zero. However, that depends on the accident you’re in. Airbags might not always be able to protect you, but they certainly increase your chance of surviving.
What triggers an airbag to go off?
Airbags usually go off when the car detects an impact of at least 10 to 16 mph. Some cars have a higher threshold limit for that because a lesser impact can be handled with the seatbelt alone. Those systems deploy airbags at a speed of not less than 25 mph.
Why did my airbag deploy for no reason?
If your airbag is deployed for no reason, that could mean there is an issue with your car. Usually, the issue is linked to a fault in the car’s safety systems. But environmental conditions or tampering with the SRS could also make it happen.
What is the price of replacing an airbag that has been deployed?
Replacing a deployed airbag can cost a lot, sometimes even more than the airbag itself. The process of replacing an airbag is complex and time-consuming, and it might cost you at least a thousand dollars.
Can airbag go off with battery disconnected? Yes, they can, because airbags have a backup power supply. So, even if the battery is disconnected, they can still do their job.
Airbags may still go off with the power supply detached from it, due to the residual energy. Therefore, it’s preferable to put off working on them for a while.