So, have you been experiencing a strange light that pops up on your dashboard and the sign looks like a man that is sitting on a seat with a big circle in front of him? In that case, you are probably experiencing an air bag sensor problem.
- Airbag History
- What Is An Airbag Sensor?
- How It Works
- Where Is It Located?
- How To Reset
- How To Replace
- Cost To Replace
- Causes Of Failure
- Cheap Sensors?
The airbag is one of the most important systems in our car, and this system is basically there to protect us in case of an accident. The airbag has to be always in good order to prevent some incidents that will have catastrophic consequences.
The air bag system is extremely smart and knows when there is an impact on the car. All of this is made possible by the great number of air bag sensors that are installed around the vehicle. These sensors basically tell the vehicle when there is a crash, and that it needs to activate the airbags right away.
All this action is performed in a fraction of a second. There are inflation systems that make these airbags explode and save your skin. That’s why airbags are important, and we are going to cover them in this article in great detail.
Here, we are going to discuss what the airbag system is, and what airbags are in the first place. We will learn what is an air bag sensor, and how this system communicates with the sensors. Plus, we’ll look at where the sensors are located in the car. So, let’s begin.
The idea of a safety system that includes airbags is very old. It takes its roots back in the early years of the 20th century. But this idea was very hard to create into practice at the time since it required some advanced technology to be developed in order to make it work. Namely the airbag sensor.
The system was firstly developed by the Japanese scientist Yasuzaburou Kobori back in 1964. However, the first successful implementation of an airbag system was in the early 70s. Many American automakers were working on the idea and GM was the most successful in this pursuit and unveiled the first airbag-equipped cars in 1973. The first airbag system was included in the 1973 Chevrolet Impala.
But these airbags didn’t see immense popularity until the 90s when they became the standard, and almost every car started to adopt these systems. All these airbags need at least one air bag sensor to work. But what is an airbag sensor?
Air bag sensors are electronic devices that are laid out in many places on your vehicle. There are a few types of sensors, there are electrical and mechanical. For example, carmakers like Toyota use electromechanical air bag sensors. Their way of deploying airbags is by using a pin that is driven into the sodium azide packets which are used to inflate the airbags.
Other automakers use different electrical sensors, and when there is a crash, the electrical circuit is complete and this activates the airbag. These electric sensors are much simpler to understand.
The job of these sensors is to react when there is an impact and activate instantly. When there is an impact, these sensors send a message to the airbag control module. Then, this airbag control module sends alarm messages to the seatbelts and the airbags.
Depending mostly on the place of the impact, the detonation of the airbags most frequently happens on the driver’s side. If there are occupants, other airbags blow up in order to deliver maximum safety for the occupants.
By looking at this, we can conclude that the airbag sensors are pretty effective at their task. But unfortunately, they can fail and cause air bag sensor failure.
When a sensor fails, it basically doesn’t work. And if your airbag is malfunctioning, it will not open in case of an accident. So that’s why we need to see how this system works in practice.
How Do Airbags Work
The air bag system is thus reliant on input from the air bag sensor. There are multiple of these sensors scattered around the car. All of these sensors are connected to the SRS module.
This module is the brain of your air bag system. This module also controls seatbelts. When there is a hit, the information from the sensor travels to the airbag module, or SRS module as it is called. Then this module is directing the airbags to explode.
Unfortunately, when these sensors are malfunctioning, they’re not sending data to the SRS module and that’s why they do not activate. If they are faulty, you will be notified with an air bag sensor light on the dashboard.
When you are seeing this light? The best thing is to address the problem as soon as possible to prevent any accidents.
Air Bag Sensor Location
Air bag sensors are scattered around the car. The frontal hit sensors are usually installed on the bumpers. Basically, they are at the same height as the bumper and where the front crash bar is located.
So, what happens if you have an impact above the headlight? For example, let’s say you hit a trailer, which is taller than the crash bar. In this scenario, the air bag sensor will not react and the frontal airbags will not deploy. So, you have to keep in mind that in some incidents, the airbags don’t deploy. So, we cannot blame the sensors for malfunctioning.
When you have a malfunctioned sensor, you will be notified by an air bag sensor light on the dashboard.
Other places where these sensors are located are on the roof and on the sides. You got to have sensors on the roof in case of a rollover, and on the sides in case of a side impact.
Some people think that there is no air bag sensor in the back. That’s not true, as there are sensors that are on the back wheel arches and these are detecting if there is a hit from behind.
The impact from behind is also dangerous and can hurt you, especially if the force is too strong. That’s why there are airbags that open and save a lot of people on the roads.
Air Bag Sensor Light
The reasons why the airbag light turns on are airbag system malfunctions. There can be four things why there is a light on your dashboard. And these things are a faulty air bag sensor, faulty airbag, faulty SRS module, or already activated airbags if you have been involved in an accident.
The first reason is the faulty airbag sensor. In order to see which of your sensors is faulty, you need to connect your car to an OBD2 scanner. The OBD2 scanner will scan your vehicle and will uncover all of its secrets. It will tell you every detail and all the parts that are malfunctioning.
But for this job, you are going to need a more advanced scanner that has a lot more options in order to dive deep and see what’s going on inside of your car.
This scanner is going to tell you everything you need to know. It will tell you if you are having a faulty air bag sensor. If you have a malfunctioned airbag or your SRS module, the OBDII sensor will inform you.
With this input, you should know what your next steps are going to be. If it’s the sensor, then you will have to replace it. This is also the same with the air bag.
You need to address these issues on time. That’s before they turn into something even worse, and if you happen to be involved in an accident, you could end up hurt much more without than with a properly functioning airbag.
Also, if your car was involved in an accident and the airbags exploded you need to recalibrate your SRS module and repair your seatbelts.
If the car was in a crash and these things were not sorted, you are having a malfunctioning airbag system.
How To Reset Air Bag Sensor
The simplest way to reset an airbag sensor is by unplugging your power cable. Just unbolt the positive cable from your battery and make sure that you keep it removed for a period of time, around 2 or 3 minutes.
This will turn the computer off and then you can plug the battery cable back in. By plugging the battery cable back into the car, you will reset everything that is inside of the car, and the systems will have to recalibrate and reset.
Another way to reset an airbag sensor is with an OBD2 scanner tool. Just connect your OBD2 scanner tool to the OBD2 port. Scan the car for errors and clear all the errors.
If some error appeared by accident, it will be removed from the car computer. If there is a serious malfunction. The error is going to be more persistent and will appear again.
So, if the error appears again on the code scanner, you have some problems going on inside your car. If it’s the sensor, then it is a good idea to locate the sensor and see if it’s plugged in correctly.
Sensors can get unplugged by accident and cause error codes to appear. You can find the front sensors around the front crash bar.
Every car is different. So, you will need to investigate more to find their correct location to replace them properly or see if they are connected.
If the SRS module is bad, then you will have to recalibrate this module. Some shops do this type of work and return defective SRS modules to life. This is a much better option than getting a new expensive SRS module for your car.
Air Bag Sensor Replacement
In order to replace the sensor, you first need to find the faulty sensor. In order to do this, you have to scan the car for codes. Make sure that you scan the car with a more advanced code scanner that will tell you the exact sensor that is malfunctioning. You don’t want to get a new sensor and then realize that this is the wrong sensor.
In order to do this job properly, you need to get the right air bag sensor. This sensor is probably going to cost you some money since sensors are not cheap. But we are going to cover the prices in the next chapter.
So, in order to replace the sensor as we said you need to scan the car for error codes. Make sure that you locate the right sensor.
Then unplug the positive battery cable. This will make sure that your airbags will not get blown up by accident. If you don’t shut the power down, this replacement can be really expensive. So, unplug the positive battery terminal.
After you have removed the positive terminal now it’s time to remove the sensor. But first, you need to locate it. It is usually found on the front crash bar but it is also useful to find a diagram of your vehicle online that will tell you the exact position. Just unplug the old one and plug the new sensor in.
Plug in the positive terminal of the battery and scan the car for codes. This is important because you don’t want the same annoying sensor lights on the dash. After you scan the car for codes, delete all the codes and you will be good to go. No more annoying airbag light on the dash.
Air Bag Sensor Replacement Cost
Sensors are usually expensive pieces of equipment. They are not cheap and cost some money to be replaced. The job of professionally diagnosing this issue is going to cost you more than $50.
Shops that offer these services usually require a hefty price in order to get these things scanned and diagnosed. Just plugging it into the computer alone is going to cost more than $50. So, keep this in mind.
If you want to take things into your own hands, you can get a scanner for a fairly cheap price. These scanners can be found on Amazon or eBay and are really inexpensive options.
But unfortunately, these scanners will not take you anywhere. This is because these scanners are reading only the codes that you later have to reference online and see what they mean. This is time-consuming in the first place. That’s especially if you have plenty of codes and you have to go through them all on Google.
Another aspect is that these scanners are not giving the right data that you need. You may Google these issues online, but they will not tell you a lot.
In order to solve this issue, you have to access each code and see the details, see which values are these codes giving in order to get the right solution.
So, a more expensive scanner will be needed and this scanner can cost a few hundred dollars.
Also, the main part is the air bag sensor. This sensor is going to cost you between $200 to $400 depending on the make and model of vehicle that you are running.
Also, the hourly rate for replacement matters. Most shops are charging between $50 and 100 per hour.
Airbag Light Repair
As we said, seeing the airbag light being illuminated can be caused by a malfunctioned airbag, a bad air bag sensor, and a broken SRS module.
We have discussed the air bag sensor, now let’s discuss the malfunctioned airbag and the broken SRS module.
Airbags are known to malfunction and stop working. This does not happen very often but it happens in some cases. But the system is smart enough to recognize this problem and detect it on time. This will result in an error code or a warning on your dash.
This warning will give you a clear idea that you are having an issue with your airbags and this has to be resolved on time.
Another reason why these lights come on is the bad SRS module. This often happens when the car was previously in an accident, but the repairs on the SRS module were not carried through.
With this broken SRS module, you are not getting anywhere. Even though you have airbags you don’t have working airbags. Since the SRS module is broken. The airbags will not deploy if there is an impact.
This SRS module has to be recalibrated and returned to working order. If you don’t have a properly working airbag system, the best thing to do is to avoid driving the car until you get all these things sorted out.
Can You Drive A Car With Bad Air Bag Sensors
You can continue driving like this, but this will be at your own risk. In case of an accident, your airbags will malfunction and you cannot know which ones will open and if some of them open at all.
In this case, you are also risking the safety of your passengers. It’s especially so if they are a lot of people in your car at the time. Even if they are not that close to you, you may end up being responsible for their death in the worst-case scenario.
In most fatal accidents usually, the side passenger is the one that bears the brunt of the impact. So, knowing this, you better get your air bag sensor and airbag light sorted out on time.
You never know what may happen and what to expect. Even if you are the most careful driver in the world. Driving a car is pure luck, to be honest. But we can also make sure that everything on our side is perfectly fine and we can hope that we are going to be safe if our airbags are in good condition.
Where To Find A Cheap Air Bag Sensor
If you can’t afford a new air bag sensor, finding a cheap second-hand sensor is also a good idea. You can find these sensors online on stores like eBay or Amazon as second-hand items. And they go for relatively cheap prices. Maybe half of the price for a new sensor.
So, these online stores are a good way to get a second-hand part. But you cannot be sure if the sensor will be good. You could potentially buy a malfunctioned sensor. There are a lot of scammers which sell malfunctioned parts and equipment out there. So, it’s best to keep your eyes open to where you buy and look for a reputable seller.
Also, if there is a junkyard near you, it is a good idea to pay them a visit. In these self-serving junkyards, you can find almost anything. And all that for a fair price. Most parts from these places are a pure bargain. So, if you have a free weekend, pay a visit to your local junkyard and see what they offer.
You will be amazed by the things that you are going to discover over there.
Air Bag Sensor: Conclusion
In this article, we have covered everything you need to know when it comes to the air bag sensor. We learned what airbag sensors are, and how they work. We also learned the integral parts of every airbag system and those are the air bag sensor, the airbag, and the SRS module.
All these integral parts form the security net for you and your passengers. Then we have covered a lot when it comes to diagnosing a bad air bag sensor using a code reader and we learned how you can replace this air bag sensor.
And lastly, we have covered the costs when it comes to replacing an air bag sensor. This is important since you have to get this part in order to make your air bag system work again.
FAQs On Air Bag Sensor
If you’re still curious to learn more about an air bag sensor, our FAQs here might help…
How Fast Does An Airbag Deploy
To ensure that you’re well cushioned and protected from an impact as quickly as possible, the airbags take little to no time to deploy. This is necessary, of course, as it has to deploy fully before your head and body impact the steering wheel, dashboard, or windscreen. A typical airbag would take as little as just 15 to 50 milliseconds to decide if it wants to deploy, based on computation data from the airbag module. And, input from the crash sensors throughout your car. Once it fully computes and does deploy, the entire airbag would deploy at a speed equivalent to between 100mph to 200mph.
At What Speed Do Airbags Deploy
Airbags are designed to cushion you against an impact, even at lower speeds. However, the minimum threshold for airbag deployment does vary depending on the circumstance. For example, if you didn’t wear your seatbelt and suffered a frontal collision, the airbags would deploy at speeds as low as 10 to 12mph. However, if you did wear the seatbelt, it would then only deploy at speeds above 16mph for a frontal collision. The logic here is that even if you suffered a serious frontal collision, at such low speeds, the seatbelt should be more than enough to keep you in place and prevent a head-on impact against the dashboard or windshield.
How Much Do Air Bags Cost
If the airbags on your car had already been deployed, you’ll need to replace them outright, as you can’t re-use an already-deployed airbag. However, the cost to replace a set of airbags alone is rather costly. And, the price varies depending on which airbag it is. For example, the driver-side airbags might cost between $150 to $600 for a single bag. A passenger-side airbag, meanwhile, is going to run you at least $300 to $800. Then, there’s the entire airbag module itself, which is another $400 to $1,200 to replace. In total then, you could be looking at between $1,000 to $5,000 (as a rough average) to replace every airbag on your car.
Where Is The Airbag Module Located
The central computing power of your car’s airbags (as well as other safety systems, such as the seatbelt and safety restraints) is the airbag module. It works by collecting impact data from numerous crash sensors throughout your car. When a collision does occur, the airbag module is able to speedily compute which airbags to deploy, and promptly deploys them. Oftentimes, the airbag module is located within the center console, or deep inside the center of the dashboard. In some cars, it might instead be found behind the steering wheel, or even underneath the driver’s and passenger’s seats.
Does An Airbag Hurt
Yes, airbags do hurt… Although, at least they prevent you from getting even worse injuries had they not deployed. When an airbag hits you, the speed at which it deploys could easily leave your face with burn marks, abrasions, and scratches. The same goes for your arms, neck, and upper torso. These burn marks are also caused by chemical burns, as the airbag emits sodium hydroxide and aerosol once it’s deployed. They’re not harmful, but they will burn somewhat. This is in addition to dust and small bits of shrapnel (it isn’t sharp or solid shrapnel, at least) that’ll explode into the air following an airbag deployment.
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