Airbag Check Guide

March 14, 2012

To ensure reliable airbag deployment, an occasional airbag check is crucial. Learn how to test for and avoid the 3 most common problems with airbags.

There are several ways to conduct an airbag check. Making sure your airbag is working properly can help reassure that you and your passengers are safe. So, check to see if your airbag system is operating correctly.

Airbag Diagnostic Tests
Most cars today can do an airbag diagnostic test. The test checks to see if all the sensors and circuits of the airbag are functioning. If the system detects any problems, it gives you a signal through the airbag indicator by flashing the light several times, giving you the specific problem the test has detected. These flashes are codes, each having its own meaning.

Airbag Diagnostic Codes
The airbag codes are double digit numbers. To read the codes, count the number of times the light flashes, wait for the pause and count the flashes again. For example, two flashes, a pause and four flashes mean that your airbag system's problem is a code 24.

Code 12 means your battery voltage is low, while 13 means the airbag circuit is shorted or grounded. Code14 means the short or ground is on the primary crash sensor circuit. You need to check if the airbag is mounted properly to your car if you read code 21. Code 22 means the safing sensor output is shorted to battery voltage, while 23 means the safing sensor input feed or return circuit is open. Code 24 means the output feed is open. Codes 32 to 35 pertain to problems with the airbags on the driver and passenger sides. Codes 41 to 45 pertain to problems with the RH and LF primary crash sensor. Airbag diagnostic codes go up to 53.

It is important that you familiarize yourself with these codes so you get the appropriate airbag repair services.

Resetting the Airbag Light
After running the diagnostic, the air bag light needs to be reset. If needed, you can ask a professional to do an airbag reset job for you. However, you can do this yourself. First, loosen the retaining nut on the negative cable wire. Then, take off the clamp from the negative terminal on your battery. Wait a few seconds before reconnecting the terminal. Put the retaining nut back on, making sure that it is tight. This should reset the airbag module. To verify that everything has been reset, turn on the ignition and check to see that the light is not flashing. If the airbag light is not flashing, then the resetting was successful.

Why There Is No Airbag Deployment after an Accident

If you've had no airbag deployment after a car accident, there may not be something wrong with your car. Airbags are an essential part of your car safety features and they can be the difference between life and death of the passengers inside the car. Here are a few common reasons why there might be no airbag deployment after an accident.

Speed Threshold
Most airbags are designed to deploy at a certain speed. Accidents that don't trip the sensor will not cause the airbags to deploy. There are cases where airbag deployment during a low speed accident has hurt the driver more than the actual accident. Most airbags are designed to have a threshold barrier of 14 mph, above which they will deploy. There is also a lower limit of 8 mph, below which the airbag will not deploy. These specifications change from model to model, so read the owner's manual completely.

Passenger Sensors
Most cars have sensors that detect the passengers sitting inside the car. That means if you have a single person in the driver's seat, only the air bag in the driver's side will inflate. Children cannot be detected by the sensors that are calibrated to an adult's body weight. Make sure that you seat children in the back seat just for this reason.

Accident Direction
The actual direction of the accident also makes a difference. For example, your front airbags should not deploy on side impacts or rollovers. This is because side airbags, curtain airbags and rollover airbags have to deploy to deal with the side to side deceleration.

There are more reasons why your airbags may not deploy after accidents. Take a closer look at the driver's manual for more information on your particular car model.

3 Common Airbag Problems to Avoid

Airbag problems can occur in nearly every car. Here are the three that occur most frequently.

  • Smothering. Airbags can inflate with so much pressure that drivers who are placed improperly in their seats can suffocate. Place yourself about ten inches from the steering wheel to get the best protection without any injuries. Airbag failure is rare, but it's a good idea to protect yourself before an accident happens
  • Facial injuries. An improperly tilted steering wheel can cause the airbag to inflate right into your face. Whiplash injuries and neck and back injuries are very common. Adjust the steering wheel so that the airbag is tilted towards your chest and not your face. If you have an adjustable steering wheel you can do this yourself. If not, get in touch with an experienced technician to have it done
  • Child injuries. Never place children in the front passenger seat where they can be suffocated by an airbag deployment meant for adults. Place children in the back seat, no matter what the situation. Use child safety devices and seat belts to protect them

Airbag Problem Recalls

In recent years, several different car manufacturers have had to call back their car models due to problems with airbag inflation. Here are a few of the well known airbag recalls that you should be aware of.

  • Honda. Honda recalled more than 80,000 models in several different countries due to defective airbags and defective airbag inflation. A press release from the company stated that defective airbag inflators were the main fault and the reason for the extensive recalls. The company also cautioned drivers that airbag inflation could result in metal fragments slicing through the bag material and injuring drivers and passengers
  • Nissan. On May 5, 2010, Nissan stated that models of 134,000 Infiniti G35 would be recalled due to the problems of defective airbag wiring and defective plugs. Other models included in the recall were the G35 Sedan models of 2005 and 2006, and the G35 Coupe of 2005 to 2007
  • Chrysler. Chrysler recalled more than 135,000 models of their Caravan and Grand Caravan models for the same reason. The problem with the airbags was attributed to water seepage into the car sensors. This would delay the deployment of the airbag in case of accidents

Take a look at the US Consumer Product Safety Commission to find the latest updated recalls made by the US government.

Where to Get an Airbag Deactivation

An airbag deactivation is necessary if you plan to get rid of your vehicle airbag system, or if you'll be dismantling certain parts of the car. This shuts off the airbag computer so that you can remove the airbags or drive without them being able to deploy.

  • Mechanic shops. Some mechanics will perform the airbag deactivation process for you. This is a fairly specialized task, however, and many mechanics are likely to not be able to do it for you
  • Specialty service shops. The best way to have your airbags deactivated, reset or recalibrated is to take your car to a special service or contractor who works on airbags specifically. Generally, these specialty services are quite expensive. It's not uncommon to spend well over $1,000 per airbag to reset or deactivate them
  • Dealerships. Some dealership mechanics will also deactivate and remove airbags for you. This depends upon the individual mechanic and dealership, so you may need to ask around in your area in order to find a worker who is familiar with the process for your particular type of car

Where to Find Your Airbag ECU

The airbag ECU, also known as the airbag crash unit or airbag crash module, is a vital piece of equipment that controls the deployment of the airbag.

What It Does
The airbag ECU constantly exchanges information with the engine. It senses a crash immediately, allowing the deployment of the airbag in a fraction of a second. The airbag ECU also stores the crash data. It's this that prevents the airbag being reused.

Replacement ECU
In the event of a crash or a fault in the system, a replacement ECU is needed in order for the airbag to work. The airbag ECU has to be removed and the cleared. A number of companies offer this service. You remove the airbag ECU, send it to them, they clear it and return it for you to replace.

A diagnostic on the ECU will not clear the airbag ECU. It has to be fully cleared in order for the airbag to be operational. When removing or installing an airbag ECU you should always remove the negative battery cable from the terminal first. After replacement, turn the key to accessories, then replace the cable. This way, you'll be out of the way in case of a malfunction that causes the airbag to deploy.

Location The airbag ECU is generally located near the gear stick of a car, usually in front or behind it. You need to remove the transmission tunnel in order to access it. In some vehicles it's located under the passenger seat or inside the glove box.

Related Questions and Answers

Do Used Airbags Have a Higher Chance of Failure?

Yes, used airbags have a higher chance of failure, as they are older than a brand new factory replacement airbag. Like any material, an airbag grows weaker over time, and the likelihood for used airbags failure is more likely because the device must be disconnected from one vehicle and installed in another. If used airbags are installed improperly in a vehicle, they may not deploy in the event of an accident, or they may cause the airbag warning light to stay lit on your vehicle, indicating an improper installation. Used airbags can help you save a little money over a new model, but ensure that used airbags are functional before purchasing them.

What Are Some Signs that You Have a Bad Airbag Control Module?

A bad airbag control module is normally signified by an airbag or supplemental restraint system warning light appearing on your dashboard. This light points to a fault somewhere in the airbag system. This fault light indicates an electrical issue in the airbag control module system that prevents the restraint from inflating properly in the event of an incident. Whenever a bad airbag control module is indicated via warning light, you should take your car in for service immediately to have the fault repaired. You can also drive with increased peace of mind after the airbag control module is repaired, as your airbags will properly deploy when needed.

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