With pillows for … diagnostics

One of the biggest problems that owners of post-accident vehicles may face is the lack of proper functioning of individual passive safety elements. The problem is the greater, the higher the level of technical perfection of the systems used in them. In such a case, even a dozen or so elements of the vehicle's passive safety system, commonly referred to as SRS, must be subjected to detailed diagnostics.

SRS, what is it?

First, a little theory. The Supplementary Restraint System (SRS) consists mainly of airbags and curtain airbags, retractable seat belts and their pretensioners. In addition to all this, there are also sensors that inform, for example, the airbag controller about a potential impact, or auxiliary systems, including the activation of an alarm, the activation of a fire extinguishing system, or - in the most advanced version - automatic notification of emergency services about an accident. 

 With vision...

 One of the most important components of the SRS system are the airbags and that is what we will be focusing on in this article. As experts say, checking their condition should begin with the so-called organoleptic control, i.e. in this case, visual control. Using this method, we will check, among other things, whether there are traces of unwanted interference on the covers and cushion covers, including, for example, gluing the joints and fixing this component. In addition, we can tell from a sticker affixed to the socket whether the serial airbag controller is installed in the vehicle or if it has been replaced, for example, after a collision. The installation status of the latter should also be checked organoleptically. The controller must be properly positioned in the central tunnel, between the driver and passenger seats. Attention! Don't forget to correctly place the "arrow" on the controller body. It should face the front of the car. Why is it so important? The answer is simple: the position of the driver ensures that the airbags will function properly in the event of an accident.

… And with the help of a tester

Before starting the test, be sure to read the contents of the sticker informing about the date of use of the airbags. The latter, depending on the car model and manufacturer, ranges from 10 to 15 years. After this period, the pillows should be replaced. The examination itself is carried out using a diagnosticoscope or a special pillow tester. These devices allow, among other things, determining the serial numbers of the airbag controller, the number of the last one installed on a given vehicle, reading possible fault codes, as well as the status of the entire system. The most extensive diagnostic scopes (testers) also allow you to display the electrical circuit of the SRS system and thus fine-tune the airbag controller. This information is especially important when the controller itself needs to be replaced.

Sensor as controller

However, as always, and in the case of airbag diagnostics, there is no single effective method for checking all types of airbags used in a given vehicle. So which pillows are a problem for diagnosticians? Side airbags in some vehicles can be a problem. These are, among others, o side airbags installed in Peugeot and Citroen. They are not activated from the main airbag controller, but are activated by the so-called side impact sensor, which is an independent controller of the SRS system. Therefore, their control is impossible without full knowledge of the type of SRI used. Another problem may be correct diagnosis of airbags installed in SRS systems equipped with an emergency power supply, or activation of airbags via AC. Fortunately, such troubles can be caused by older cars, mostly from Volvo, Kia or Saab.