SRS Light on: how would you diagnose (2nd of 2 lights on my son's D2)
 

Hi all.

Same story as my other post: Son just came home for the holidays from college, and (as usual) there are a couple of new lights on.

One is the SRS light on the dash.

How would you recommend troubleshooting it?

Seems like it could be three (3) things: air bag itself, the rotary collar (clock spring) or the wiring from the collar to whatever controller manages the air bag. Guess it could also be one of the other airbags in the car as well?

I checked the other functions -- horn, audio, cruise -- that also go thru the rotary collar/clock spring, and they all seem to work fine.

Would this eliminate the rotary collar? Wish this were the issue because it seems pretty straightforward to replace.

If no the collar, how would I check/test the steering wheel airbag itself without setting it off, side curtain airbags (same problem), and the wiring from the airbags to the controller.

Anyone who could help me with the best (read shortest) steps to diagnosis/fix, it would be most appreciated.

Check the connections for the seat belt tensioners they can get knocked loose or gunked up and cause the light to come on

So the SRS signals an issue with more than just the airbags?

Is there a list of all the things that can be traced to an SRS light being on?

Want to start with the easiest/most likely and work my way down the list (starting with the belt tensioners).

Now one question re. the tensioner. Does it use the same ground as the door locks and windows.

My son's D2 has a rear driver window that can be balky, a rear driver side door lock that doesn't work.

It seems that the tensioner sensor might well be in the same harness branch as these two other features.

Thoughts?

The SRS light can be on for any fault in the restraint system. This could be a bad rotary coupler, bad airbag igniter in any airbag, bad connection somewhere, bad seatbelt pretensioner, bad crash sensor, etc etc. You will have to get it scanned by someone with a capable scanner .The light will NOT go off after repair unless cleared with a scanner able to communicate with the system

In the case of my truck, the fault turned out to be a short in the connector at the DCU under the console. It can be time consuming to diagnose. It was in the case of my truck. Here's a link to my saga.



And Bill, the answers to all your questions about how the system works and is connected are in the Restraint Systems section of the RAVE DII workshop manual. If you don't have a copy of it you can download it from the site linked in my signature.

OK, pulled the SRS codes and had a single fault with the message

"open circuit fault airbag circuit"

or something like that. May have mentioned the steering wheel or front, can't remember?

Does that eliminate the tensioners and point back to the rotary collar?

Depends on which airbag. The driver's airbag circuit runs through the rotary coupler; the passenger airbag does not. But yes, the pretensioners appear to be out of scope. Plus again, as in my case, it was a fault in the connector at the DCU that was reading as an airbag circuit fault.

You can and should diagnose connectivity with a multimeter to isolate the problem. That's how I determined the problem was in the connector and not the airbag itself or the rotary coupler. It is often time consuming and tedious, but the mantra is diagnose, diagnose, diagnose to avoid throwing parts at symptoms.

Thanks.

My normal modus operandi is to start throwing parts at it, but I'm trying to be more disciplined.

Yes, I have the RAV manual and will look at, but in the meantime where do the aribags terminate to a body control or similar unit?

I thought I saw somewhere that the leads from the aribags go thru the rotary coupler then in/under the center console?

I thought all the controller's were under the dash, behind the glovebox.

My SRS light has been coming on randomly the last couple of months also. I don't know if it coincidence or not, but cycling all of the seatbelts seems to make it go away.

That's a real easy way to have an airbag blow up without giving the rest of the diagnostic information .
Airbag should be disconnected from harness before any SRS circuit is tested. .....
And yes, I have seen it happen.