Home » Automobile engg » How Does the SRS Airbag or SRS System Works? [Explained]

How Does the SRS Airbag or SRS System Works? [Explained]

The SRS airbag system is one of the most important car interior parts. You might have probably come across the SRS light and wondered what it means. If your goal is to learn about SRS, then you are in the right place.

This article gives an overview of:

  • What SRS System is
  • Components of SRS system
  • Functions of SRS system
  • What turns SRS system light on and how turn it off

What Does SRS Mean?

Every vehicle has SRS displayed on its steering wheel or dashboard. In cars, it means “Supplemental Restraint System.” It has the critical function of controlling automatic seatbelts, restraints, and airbags. The primary purpose of SRS is to protect the driver and the passengers during collisions.

The SRS system automatically detects braking, deceleration, impact location, and the presence of a passenger on the front seat. After detection, it sends a signal to the airbag control unit to determine which seat belts should be tightened and which airbags to activate.

Basic SRS Components

Airbags have several components, each with a specific function. The components work together to ensure that inflation occurs at the right time. Here are the seven components of SRC;

#1 Inflator

An inflator is part of the airbag module whose function is to inflate the airbag before it comes out to protect the driver and front-seat passengers. The inflation system works by mixing potassium nitrate and sodium azide to produce nitrogen gas for instant inflation.

#2 Impact Sensors

Impact sensors usually “notify” the airbag system of any impact; thus, they let it know when to inflate. In other words, impact sensors activate the SRS system if there is a sudden halt in acceleration while driving at 15 miles per hour or more.

#3 Indicator Lamp

This is the warning light for car SRS. It usually illuminates for a few seconds during diagnostic checks if the airbag system is working normally. However, if SRS has a problem, the indicator lamp will remain lit.

#4 Clock Spring

The clock coil spring connects the airbag to the steering wheel. This only applies to the driver’s side and not the front passenger seats. The clock spring has a wound wire that allows the steering wheel to rotate without interfering with the electrical connection to the car horn, airbag, and steering wheel.

#5 Airbag

The airbag is a bag that inflates the front of the front passenger or the driver to reduce the impact of the collision on the body. It is shielded from scorching by a heat shield coat. Most airbags are made from nylon fabric material.

#6 Wiring Harness

A wiring harness is a series of wires that connect the various airbag system parts. Suppose any of these wires disconnect or malfunction; then the entire airbag system is out of order.

What Can Cause SRS Light

SRS light demonstrates a problem with airbag systems. Some vehicles display SRS letters, while others use a stick figure. Still, in some vehicles, the light resembles a buckled-up person with an airbag in front of them. Several issues can turn on SRS lights. However, the best way to determine the exact problem is to use an airbag diagnostic scan tool. The most common causes of SRS lights are;

Faulty SRS Computer

Faulty SRS computers can occur due to aging, excess vibration, and water damage. For this case, you may need a repair or replacement.

Previous Collisions

Suppose your airbag fails to deploy after an accident, then SRS lights will turn on. It occurs because collisions trigger crash sensors.

Failure of SRS Battery Backup

SRS computers need backup batteries to keep any data it receives; they work even when cars are off. Therefore, if the battery is low or dead, then SRS lights will go on.

Defective Clock Spring

A Clockspring maintains the connection between the steering wheel and the SRS computer even when turning the wheel. Suppose it is not working; the driver’s side airbag may not deploy during accidents. In addition, the SRS light also notifies you by turning it on.


The corrosion is primarily due to water damage. Corrosion not only turns on SRS lights but also reduces the efficiency of the SRS system.

A Defective Seat Occupancy Sensor

Whenever a passenger occupies the front seat, a sensor updates the SRS system of their presence and weight. If this sensor malfunctions, the SRS light may turn on.

Seat Belt Latch Failure

SRS systems have sensors to monitor seat belt fastening. However, suppose something gets into the belt buckle; it may interfere with the connection. Thus you may need to clean foreign objects.

How to Turn SRS Light Off

SRS lights are a warning of airbag issues. Whenever they are on, it means there is an issue that needs fixing. Resetting the light will not solve anything; you must resolve the underlying issue before turning off the lights.

There are three steps of putting off SRS lights:

  1. Insert the key into the ignition and turn the switch to the “on” position.
  2. Press and hold the reset button on the trip odometer
  3. Turn the ignition button to the “on” position. Do not start the engine; instead, continue holding the trip odometer reset button till “00000” appears on the trip button and the lights go off.

In summary

SRS is essential for reducing both the long and short-term consequences of an accident on the driver and front-seat occupants; therefore, it requires regular maintenance. Suppose its lights turn on, don’t be ignored but instead diagnose and fix the causative issue.

Resetting won’t help; instead, you can use the SRS OBD2 scanner to fix the issue and reset the SRS lights. Don’t take your life for granted; thus, improve your safety by ensuring your airbag is in perfect working condition.

So for now, I hope that you have learned about the “SRS Airbag“. If you have any questions or doubts about this article, feel free to ask in the comments. If you got this article helpful, please share it with your friends.

Want free PDFs in your inbox? Then subscribe to our newsletter.

Read more in our blog:

  1. What are the different Types of Transmission System? [PDF]
  2. The complete list of Car Engine Parts [Explained with Functions] (PDF)
  3. What are the Engine Performance Parameters? [Definitions & PDF]
About Tim Miller

My name is Tim Miller - a car mechanic and blogger. I come from Denver, Colorado. Cars, Engines, and Mechanic Tools are everything to me and they drive me to discover more and more.

2 thoughts on “How Does the SRS Airbag or SRS System Works? [Explained]”

  1. Wow, this article helped me to understand how SRS Airbag really works. What a great read.


Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.