From time to time, I'll get asked about an issue where the customer has no communication with the airbag control module.
( ACM ) (Sometimes also referred to as: RCM - Restraint Control Module ; DERM or SDM - Sensing Diagnostic Module ; SRS unit / SRSM module - supplemental restraint system ) When I do hear about this issue, its when I speak to customer's who have already sent in the module to us for reset, but sometimes it happens as of result of something before the reset.
The main reason I wanted to write this article is to help you guys know in advance! (without having to actually pay for a reset or anything)!
The interesting thing with this problem - There isn't ONE specific problem that always causes this problem. There can be different causes and different solutions! Here's a few that I've come across over the years... Many of my customer's are
highly experienced Body Shop owners and Professionals will find these pretty simple and common knowledge. If thats you, Just think of some of these as refresher or a "check list"
The Problem: "So you have an airbag light on but you are not able
to pull any airbag codes from the airbag system at the moment..."
Airbag Module "No Communication" issues commonly fall into these problem areas:
Common Causes:
Communication Pins at plug - Inspect the communication pins where the harness plugs into the front of the module. Look for signs for corrosion or damage. Those pins sometimes can become bent, pushed back in or even broken off.
Module is improperly grounded - A simple but overlooked problem. Module has to be completely bolted down / installed as designed.
The Scanner - Make sure the scanner being used to read the airbag diagnostic codes is able to: *access the airbag system. Many scanners are set to read just the basic engine codes. *support the Year Make Model of the vehicle. Some scanners may be outdated. This problem is more common with newer year vehicles.
Wiring or Harness around the airbag control module shouldn't be severed or damaged anywhere (not very common... but a possibility)
Finally - If all these common problem areas all check out fine, then the final possibility to consider is that the airbag module is internally faulty / fried. Because the module is basically a electronic circuit board this can be caused by a very wide range of reasons. If you determine that is the case, there would be no benefit to have the module reset. There would be no benefit to send it in for a reset. We do keep a very
large inventory of airbag modules. If we have one that matches your module, we can ship it out to you. Your original module's part number has to match the one we are sending to you. If you want to purchase a replacement from our stock, reply to us with your part number. (or
search our inventory on
myairbags.com ) (side note - on some vehicles... when you use a module that is not original to your car, no matter - new or used, you may have to "marry" it to your car using a scanner. This is why most people prefer to use our reset service... when possible) I know this article will help point a lot of you folks in the right direction. If it doesn't give you any direction, please let text, email or call us.
Together, we will continue to try to figure this out for you.