Air Bag Sensor

Air Bag Sensor – How To Fix A Malfunctioning Air Bag Sensor?

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.

The airbag is one of the most important systems on 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 bad system is extremely smart and knows when there is an impact to 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.

History Of The Airbag System

Transmission Leak Repair Costs

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 of the 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 saw 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?

What Is An Air Bag 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 Does The Airbag System Works?

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 the 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.

Where Are The Airbag Sensors Located In The Car?

Air bag sensors are scattered around the car. The frontal hit sensors are usually installed on the bumpers. Basically, they are on 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 open. 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 (thank God) open and save a lot of people on the roads.

What Are The Reasons Why The Airbag Light Turns On?

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 An Airbag Sensor?

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 like 2 or 3 minutes.

This will turn the computer off and then you can plug the battery cable back in. With plugging the battery cable back to 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 of 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.

How To Replace An Airbag Sensor?

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 going to 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.

What Is The Cost For Replacing A Bad Airbag Sensor?

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 which 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. This will be good to know and what you can expect from this.

What Can Cause Your Airbag Light To Come On?

As we said, airbag light can be caused by a malfunctioned airbag, bad air bag sensor, and 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.

What Will Happen If I Continue Driving Like This?

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 Cheap 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 that 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.

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1 Comment

  • John W. Sullivan Says

    Yes sir they have us drivers right by the balls Those sensors you would think would be able to be reconditioned and not recycled and the malfunctioning parts replaced but no… nobody makes money that way.. those should be able to be reconditioned. They aren’t like a rubber tire which just wears due to surface contact with the road. or brake shoes which ironically can be reconditioned simply because all is not useless when one part is worn. Alternators, starter motors, and such are reconditioned and helps to save us money.. not a lot but some. Oh yes, this is a complicated issue. Does the end justify the means though? We are needlessly using up our planet’s resources… all in the name of money. I believe we are being taken for one hell of a ride. Enough said.

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