What Is the Airbag Control Module and Its Replacement Cost?

airbag control module

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Many people can’t help but express appreciation for the invaluable protection airbags can bring. With this safety device, drivers and passengers have the last defense against serious injury or the possibility of death that come with road accidents

Yet, with all the technological sophistication with which airbags are made, they can only provide maximum protection. Owing to factory defects or owner misuse, airbags have been themselves the cause of injury in the past. 

This calls for a complete understanding of how these tools should be properly used and the mechanism with which they are designed to be operated or controlled. The mechanism being referred to is the airbag control module

What is an Airbag Control Module

The airbag control module is the controlling computer for a car’s airbag system. Other names used for it are Airbag ECU and SRS ECU. SRS stands for Supplementary Restraint System.

Monitoring the car’s airbag system has two main purposes: 

  • The module keeps under a systematic review the airbag system for functionality.
  • The module also recognizes signals that will indicate a collision. It then deploys not only the airbags but also other safety features such as seat belt pretensioners.

The module looks like a case of an average size of 10 sq. cm, and carries an electrical socket. Normally, you would see a sticker on it with details like the manufacturer, serial number, part number, and the airbag or SRS icon.

Besides the main function of monitoring the airbag system and deployment of airbags, the module also stores crash data and exchanges information with the engine of your car.

Even if the bags have not been deployed in a case where there is no actual collision, the module can give you valuable information/details of the incident.

During a minor impact, the sensors induce the module to “wake up” and then the module stores information in a downloadable memory. Up to 8 seconds of information before the impact can be collected and stored.

Information that can be obtained include:

  • Vehicle speed
  • Engine speed
  • Throttle position
  • Brake light switch (whether ON of OFF)
  • Impact speed change
  • Airbag deployment
  • Seat belt use
  • Seat belt pretensioner deployment
  • The stored information can be used in legal disputes, and it is not illegal for you to download it when necessary.

    If you own the car, such information is yours. If it isn’t, but the vehicle is part of the evidence in a legal case, the information contained in the module is also part of the evidence.

    Permission to inspect the vehicle along with the stored information should be obtained from the authorities.


    Airbag Control Location

    Typically the airbag control module is located in the center front of the cabin of a vehicle and bolted to the floor.

    However, depending on the make and model of your vehicle, the location of the module may be at the kick panel, under the radio or behind the steering wheel.


    Replacing/Resetting an Airbag Module

    Replacing Airbag Module

    A faulty SRS module needs to be replaced immediately. If your module is faulty, the airbags of your vehicle may not be able to protect you and your passengers. One sign of malfunction is the Airbag light / SRS light being “ON” though the car has not been involved in an accident.

    In this case, the data in the module may have been corrupted, or the module itself is damaged, or it has been exposed to water. Generally, the solution for such cases calls for a replacement of the unit.

    The SRS light being “ON” may also be interpreted as just a need for resetting the module. If the car has been involved in an accident and the bags have been deployed during that time, the airbags need to be replaced and the module reset.

    It is advised that you don’t go to a car dealership if all you need is to reset the module, and in cases where a replacement is called for, it is not at a dealership that you are recommended to go. This is because it can cause you a huge out-of-pocket expense.

    Why? Often, car dealerships need to special order the airbag module, which means incurring more fees in the process.

    Rather, look for an affordable repair service that can save you hundreds of dollars. Usually, they do more than just repair the damaged part – they go look for the root of the problem and upgrade components if needed.


    Remove Airbag Control Module for Reset

    In case you need to remove the airbag control module on your own, here are the steps:

  • Disconnect the positive lead on the battery.
  • Wait for three minutes before removing the module. Unplug the airbag control module harness wiring plugs.
  • Send the module to a technician to reset.
  • Remove Airbag Control Module

    Airbag Module Installation

    After the reset airbag control module has been done, you may want to install it yourself. Do the following:

  • Check if all components of the module are properly connected.
  • Disconnect the battery terminals.
  • Insert the module into its compartment and then connect all the harness wiring plugs. Fasten the module in place carefully.
  • Reconnect the battery terminals.
  • Airbag Module Replacement Cost

    Do your research seriously when looking for a good, but affordable service because if indeed the problem calls for a replacement, a new airbag module installation can cost you up to $5000. Costs vary depending on the make and model of the vehicle.

    Basically, the cost also depends on the number of parts that may also need to be replaced along with the module. The prices of these other parts to be replaced also differ from vehicle to vehicle. 


    Safety Instructions

    Be very careful when resetting or replacing the module. Failure to follow instructions can result in injury due to accidental airbag deployment. Read your service manual carefully.

    The following needs to be strictly observed:

  • Do not probe the electrical connectors found in seat belts and airbags.
  • Do not tamper with these parts: safety belt buckle, retractor pretensioners, safety belt inflators and adaptive load limiting retractors.
  • Turn the ignition switch off before disconnecting the battery cables.
  • Stick with the 3-minute rule when servicing the module. Before 3 minutes have passed, there is still a good chance for airbag or seat-belt pretensioner to take place.

  • About the Author Simon Adams

    Simon graduated with a Mechanical and Electrical Engineering Degree. He has over 20 years of servicing experience in both Japanese and German car dealerships. He now acts as a freelance mechanic's instructor for local schools.

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