Daleford

I am repairing a 2012 Civic LX that had a minor front end collision. The passengers air bag deployed and the drivers bag didn't. Can anyone explain how this could happen? Driver not wearing his seat belt possibly, although both drivers and passengers seat belts are blown.
I had the system scanned and it is not showing any codes for the control module! How can this be if it blew 2 belts and the RH bag?

ezone

I suppose there is a warning light on for the SRS, right?

Try using a dealer level scanner, there should be deployment codes stored that are permanent and cannot be erased.
Unless someone already replaced the control unit? No, there would be other fault codes.

Do not trust any fault codes (except the deployment codes) that come from an SRS unit that has fired charges. Get your new control unit installed, then see if there are new fault codes, and go from there.

Follow the official SRS replacement parts list according to whatever items were deployed, for safety and liability reasons.


One more thing: BEFORE ordering an SRS control unit, impact sensors, etc. get them out and see who made them.
It will be either TRW or Continental.
You MUST get the correct manufacturers parts, they cannot be interchanged.

(Honda changed SRS suppliers during the production run of the 12 model year, this is why you need to check whose name is on the system.)

Probably hit harder on the side that blew the bag.
The system decided this is what needed to be deployed. Was anyone killed in the accident? No? the SRS system worked OK then LOL


HTH

Daleford

Yes, the SRS light is on and no, nobody got hurt I don't think.
I did notice on car-part.com they list 3 different control boxes. Mine is a TRW.
So even though the control is not putting out any codes, that means nothing?
Because it has fired, get a new control, correct?
Thanks for the info.

ezone

Used? 3 different choices? Uhhhh.....
My advice:
Buy a correct new unit, looked up in a real Honda parts catalog by entering the vehicles VIN.
Don't skimp on safety.
I know I don't ever want to be standing in front of a judge and jury explaining why any airbag related item wasn't 100% on a car I repaired.


The TRW SRS listing in this dealer parts catalog says SRS UNIT (REWRITABLE) (TRW) ('11-'12, VERIFY SRS UNIT MFR.& SRS UNIT P/N B4 ORDERING)
Yeah, it actually says B4 like it was written by a bunch of 12 year olds LOL

If it's deployed any charges, there will be permanent codes stored.
Period.

WHY someone can't read those codes may be an entirely different matter. Scanner compatibility issues are always a possibility if one doesn't have the Honda HDS scanner (I'm not saying the dealer scanner is perfect by any means LOL but it's best suited for the job)

It's also possible there may be a problem or fault codes related to the gauge control module, it controls the SRS light per request from the SRS control unit via the F-CAN bus.

Don't forget wiring too.
There's a whole troubleshooting guide for covering 'no communication with the Honda HDS scanner'.

AAAaaand give this PDF a read: https://www.google.com/url?sa=t&rct=...mgVoTAujLNIu3w

Yes, standard procedure. Plus impact sensors and all the deployed items.

A collision list copied and pasted from Hondas service info:

After a collision where the front seat belt tensioners deployed, replace these items:
• SRS unit
• Front seat belt(s)
• Front impact sensor(s)
After a collision where the front airbag(s) deployed, replace these items:
• SRS unit
• Deployed front airbag(s)
• Front seat belt(s)
• Front impact sensor(s)


There's a lot more on the list to be replaced if it fired the side airbag(s) or side curtain airbag(s).

Once the new SRS control unit is installed, connected, etc., it has to be initialized. Calibration of the seat weight sensors and occupant detection systems must be completed before the system is considered operable.

Then you can check for new fault codes that weren't readable with the blown original control unit, and fix those. (Bodyshops and insurance adjusters just love when I tell them about this part of the job LOL)


HTH

Daleford

I do thank you for your information and time spent. Although expensive, will consider all.
Last question: When they say replace belts, must both ends be replaced? The retractor end for sure but can the buckle end be reused as one would think that it would not be affected.
[on a budget but be assured I am picturing that judge that you mentioned]
LOL

Mad Dog Tannen

I just put a piece of tape over my SRS light on my Volvo, but then again it was a Volvo (safe anyways).

ezone

Just the retractor(s) that were deployed.

AFAIK that model doesn't use explosive charges on the buckles (but many other cars sure do)...So unless physically damaged-- the buckles should be OK.

You touch an airbag, someone could try to hold you liable for anything related to it. And it may not be just the shop that suffers, they can go after you personally and everything you ever thought about having.

Sure seems like almost anyone in this country could be looking for a free ride, lawsuits are a damn quick way to become a millionaire.
Our shop has been called into court over much more trivial things in the past (service manager handled it), I just know I'd sure hate for it to be over anything related to a safety system I had my fingers in.

Judges and juries are never 'car people'.
Guess who they tend to rule in favor of?
They have no sympathy for a humble mechanic, and cutting corners doesn't fly at all in a courtroom.
I try to document everything and follow the manufacturers' printed recommendations. CYA all the way.

/pessimistic rant

Daleford

Ezone - once again I thank you for all your info.
BTW, the buckle end does have 2 small wires going to the head but one would assume they would be for a belt warning [not clicked] light.

ezone

Correct....

FYI that buckle state data is also used by the SRS control unit, so a bad buckle switch can result in an SRS warning light and corresponding code.