Airbag Light -- New Variety

[1schoir]

MY97 Base Boxster, 16K miles (long story about mileage).

The airbag light has been on more than it has been off since I bought the car 2 years ago. Initially, I replaced both seat belt buckles with the recommended parts and reset the light with my Durametric.

I later learned of an updated (superceding) TSB (number 6924) which also recommends installing "service set belt buckle" (2 sets) and bought the two sets but have not yet installed them. When the airbag light goes on now, the Durametric reads codes as follows:

Fault Number: 21

Description: Ignition circuit, driver

Repair Infomation: This code applies to the driver airbag, and the connection between the steering wheel and the airbag.

If I reset it, it displays the same fault again within 1 second of pressing "clear codes."

Once in a while, in addition to displaying fault number 21, it will simultaneously display the following (the previous fault number 21 always pops up):

Fault Number: 45

Description: Belt buckle, driver

Repair Infomation: Driver side belt buckle may have been unplugged at some time, check connector to belt recepticle.

If I clear this fault code, it will not reappear for 5 or 6 miles.

The question is how to proceed? Do I first follow the steps in the TSB for installing the "service set belt buckle", which is essentially a set of ground wires, connectors, heat shrink tubing, etc. , and which are installed to create a better ground for the seat belts?

Or, do I first deal with the steering wheel ground issue? If so, how do I cure this apparent airbag to steering wheel ground problem?

Note: I removed the steering wheel and sprayed some DeOxit on the connectors I could see, but that did not resolve the problem.

Any suggestions or comments or photos of which ground is involved with the steering wheel much appreciated.

Regards, Maurice.

[rsfeller]

Maurice,

Got great answers but some info:

When I bought my 2.5L used I had similar issues and although I know I had the seatbelt fault I believe I saw the air bag (SRS) fault you mentioned. I'm trying to check my screenshots of the durametric to "back this up".

I bought the kit buckles and ground set too. I noted when I got everything apart that the ground wires appeared to have been done by the PO so I sent the kit back and installed the buckles. That problem never reared it's ugly head.

About the same time I replaced the horn issue with the bad bushings in the air bag frame. After that was fixed (which included disengaging the air bag lead) and putting it back on the "other error" never appeared again.

I don't have you answer but getting the air bag out is a 10 minute job. It may be worth checking the wires in that area for cuts/chafes. I don't recall how the circular spring wiring is in the Boxster but in my Saabs their failure has always triggers SRS lights. I've relplaced the twice in my Saab with 260K miles.

Shawn

Ohio

[1schoir]

Maurice,

Got great answers but some info:

When I bought my 2.5L used I had similar issues and although I know I had the seatbelt fault I believe I saw the air bag (SRS) fault you mentioned. I'm trying to check my screenshots of the durametric to "back this up".

I bought the kit buckles and ground set too. I noted when I got everything apart that the ground wires appeared to have been done by the PO so I sent the kit back and installed the buckles. That problem never reared it's ugly head.

About the same time I replaced the horn issue with the bad bushings in the air bag frame. After that was fixed (which included disengaging the air bag lead) and putting it back on the "other error" never appeared again.

I don't have you answer but getting the air bag out is a 10 minute job. It may be worth checking the wires in that area for cuts/chafes. I don't recall how the circular spring wiring is in the Boxster but in my Saabs their failure has always triggers SRS lights. I've relplaced the twice in my Saab with 260K miles.

Shawn

Ohio

Shawn:

Thanks for the info. Will definitely check the wires for cuts/chafes as this most recent variety of airbag light only reared its ugly head about 3 months ago.

Regards, Maurice.

[1schoir]

Maurice,

Got great answers but some info:

When I bought my 2.5L used I had similar issues and although I know I had the seatbelt fault I believe I saw the air bag (SRS) fault you mentioned. I'm trying to check my screenshots of the durametric to "back this up".

I bought the kit buckles and ground set too. I noted when I got everything apart that the ground wires appeared to have been done by the PO so I sent the kit back and installed the buckles. That problem never reared it's ugly head.

About the same time I replaced the horn issue with the bad bushings in the air bag frame. After that was fixed (which included disengaging the air bag lead) and putting it back on the "other error" never appeared again.

I don't have you answer but getting the air bag out is a 10 minute job. It may be worth checking the wires in that area for cuts/chafes. I don't recall how the circular spring wiring is in the Boxster but in my Saabs their failure has always triggers SRS lights. I've relplaced the twice in my Saab with 260K miles.

Shawn

Ohio

Shawn:

Thanks for the info. Will definitely check the wires for cuts/chafes as this most recent variety of airbag light only reared its ugly head about 3 months ago.

Regards, Maurice.

Anybody know how many ground wires exist between the air bag in the steering wheel and the car chassis and between the steering wheel and the car chassis? Locations?

Regards, Maurice.

[juniinc]

OK Maurice, I bet it is your seat buckle receptacle. According to my experience & research the most frequent cause is a fault in the relay in the seat belt. 986 has a relay that detects and records whether the seat belt was being worn if the airbag deploys. You would most likely have to replace your seat belt buckle receptacle(986 FAQ). Also I've seen some cases related to faulty reading, all it needed was computer to be reseted. Same thing that happened to my 350 Z last week.

Maurice,

Got great answers but some info:

When I bought my 2.5L used I had similar issues and although I know I had the seatbelt fault I believe I saw the air bag (SRS) fault you mentioned. I'm trying to check my screenshots of the durametric to "back this up".

I bought the kit buckles and ground set too. I noted when I got everything apart that the ground wires appeared to have been done by the PO so I sent the kit back and installed the buckles. That problem never reared it's ugly head.

About the same time I replaced the horn issue with the bad bushings in the air bag frame. After that was fixed (which included disengaging the air bag lead) and putting it back on the "other error" never appeared again.

I don't have you answer but getting the air bag out is a 10 minute job. It may be worth checking the wires in that area for cuts/chafes. I don't recall how the circular spring wiring is in the Boxster but in my Saabs their failure has always triggers SRS lights. I've relplaced the twice in my Saab with 260K miles.

Shawn

Ohio

Shawn:

Thanks for the info. Will definitely check the wires for cuts/chafes as this most recent variety of airbag light only reared its ugly head about 3 months ago.

Regards, Maurice.

Anybody know how many ground wires exist between the air bag in the steering wheel and the car chassis and between the steering wheel and the car chassis? Locations?

Regards, Maurice.

Edited October 12, 2007 by juniinc

[tonymccandless]

Maurice

Any progress yet ? Believe it or not our 1998 2.5 is now showing same problem and excellent indie in Scotland is having a hard time getting it sorted. We replaced the spool in the steering wheel a few months ago which had started breaking up and since then that dammed light won't go off and gives out the same error code 21 as yours.

He is working on it today after doing all wiring traces yesterday and is going to swap in another airbag from a Boxster in for service to see if it gives different readings and the light goes off.

V.frustating as we have sold the car and said we would get the light fixed before handing it over. If this takes any longer we will be abel to hand it over as a vintage :D

[1schoir]

Maurice

Any progress yet ? Believe it or not our 1998 2.5 is now showing same problem and excellent indie in Scotland is having a hard time getting it sorted. We replaced the spool in the steering wheel a few months ago which had started breaking up and since then that dammed light won't go off and gives out the same error code 21 as yours.

He is working on it today after doing all wiring traces yesterday and is going to swap in another airbag from a Boxster in for service to see if it gives different readings and the light goes off.

V.frustating as we have sold the car and said we would get the light fixed before handing it over. If this takes any longer we will be abel to hand it over as a vintage :D

Tony:

Some work, but no definite progress yet. I removed the air bag on the steering wheel again and cleaned all of the contacts between the airbag and steering wheel and any grounds to the chassis in that area, after removing the instrument cluster. Fault code 21 is still there, as are the seat belt buckle codes.

I am going to attempt to attack this in reverse, i.e., by pulling out the seats and installing the "service belt buckle sets" on both sides according the the TSB (#6924, dated 01/04) to try to get rid of those codes first.

If I get really lucky, it might be that my Durametric is mistaken and the "21" code is really not called for. We'll see.

If your mechanic pinpoints something definitive, please let me know. I'll keep you posted as well.

Regards, Maurice.

[tonymccandless]

Maurice

Feedback from mechanic is no progress and he cannot find the cause. Looks like only hope is for you to get a result with the seat belt buckle replacement.

[Loren]

Folks -- if you have seat belt codes fix those first. That fix also includes fixing the grounds which could cause many other faults.

[tonymccandless]

Thanks Loren

Car is being put back together now and Peter is checking the wiring on the passenger and driver side floor pans. He stated that you can get kit for this but he uses his own fix. Sounds as if it might be linked to other reference I read to grounding problems.

He mentioned that his experience on seat belt reference was to do with the tensioners. Not sure if this is in line with experience from the folks here or not.

Btw where do I get hold of the TIB's that refer to this ?

[1schoir]

Thanks Loren

Car is being put back together now and Peter is checking the wiring on the passenger and driver side floor pans. He stated that you can get kit for this but he uses his own fix. Sounds as if it might be linked to other reference I read to grounding problems.

He mentioned that his experience on seat belt reference was to do with the tensioners. Not sure if this is in line with experience from the folks here or not.

Btw where do I get hold of the TIB's that refer to this ?

Tony:

The prevailing wisdom is that the airbag light is caused by a defective/insufficient ground not on the tensioner side, but rather on the seat belt buckle side (female side).

The Technical Service Bulletin that deals with this issue is number 6924, dated 21JUL04. It deals with fault codes 45, 46, 48 and 49.

One way to get access to the TSB's is to become a contributing member of RennTech.org (click on "Quick Menu" above and scroll down to "Current TSB's).

Regards, Maurice.

[1schoir]

Folks -- if you have seat belt codes fix those first. That fix also includes fixing the grounds which could cause many other faults.

Well, I have now replaced both seat belt buckles and installed/spliced/soldered all of the "gold plated and greased" leads and the ground leads that come in the "service set belt buckle" on both sides of the car. It was a straightforward procedure once the steps in the TSB were translated into real world language. I've got lots of photos and may do a write up of that procedure when I get some time.

The good news is that I have now gotten rid of all the seat belt related fault codes that it was previously exhibiting. :clapping:

The bad news is that I still have the Fault Code 21 (ignition circuit driver- Repair Infomation: This code applies to the driver airbag, and the connection between the steering wheel and the airbag) and that after I clear it with the Durametric unit, the airbag light comes back on, along with the code, although now, instead of reappearing instantaneously, there seems to be a lag of 2 seconds before it reappears (could be my imagination). :o

Any additional info as to specific points where the driver airbag connections between the steering wheel and airbag would be appreciated. The last time I had it open, I thought there was only one connection between the airbag and the steering wheel. Am I missing something?

Regards, Maurice.

[Loren]

Usually that means the connection is open - not connected.

Like someone remove the steering wheel and forgot to hook it back up - or broke the clock spring on the steering wheel connection.

Best take the steering wheel off and have a look -- with the battery disconnected and the key OUT of the ignition.

[1schoir]

Usually that means the connection is open - not connected.

Like someone remove the steering wheel and forgot to hook it back up - or broke the clock spring on the steering wheel connection.

Best take the steering wheel off and have a look -- with the battery disconnected and the key OUT of the ignition.

Loren:

Thanks for the info. I will remove the steering wheel and examine those components closely and post results.

Regards, Maurice.

[mikefocke]

And do do the write up for the TSB work you did so others can benefit.

Good luck in finding the cure.

[1schoir]

Folks -- if you have seat belt codes fix those first. That fix also includes fixing the grounds which could cause many other faults.

Update.

Well, this should come as no surprise to anyone on this board for any length of time, but...Truer words were never spoken.

Approximately four weeks after I had completed the airbag light TSB procedure, I was about to remove the steering wheel again to see if I could isolate the cause of the remaining Fault Code 21 but I decided to reset the airbag light one more time with my Durametric before proceeding.

Surprise! Now the light did not come back on immediately, and it has not come back on since.

The only thing I can think of is that after the TSB procedure (which involved fixing the grounds and replacing leads causing the seat belt codes as described above), it took a number of cycles for the fix to take effect on that fault code. As Loren said, "fixing the grounds which could cause many other faults" may have been the key.

No airbag light on in the dash is quite a relief after more than a year of constant on.

Regards, Maurice.

[juniinc]

Hey Maurice , thought I mentioned it - all it needed was computer to be reseted,,,LOL

Folks -- if you have seat belt codes fix those first. That fix also includes fixing the grounds which could cause many other faults.

Update.

Well, this should come as no surprise to anyone on this board for any length of time, but...Truer words were never spoken.

Approximately four weeks after I had completed the airbag light TSB procedure, I was about to remove the steering wheel again to see if I could isolate the cause of the remaining Fault Code 21 but I decided to reset the airbag light one more time with my Durametric before proceeding.

Surprise! Now the light did not come back on immediately, and it has not come back on since.

The only thing I can think of is that after the TSB procedure (which involved fixing the grounds and replacing leads causing the seat belt codes as described above), it took a number of cycles for the fix to take effect on that fault code. As Loren said, "fixing the grounds which could cause many other faults" may have been the key.

No airbag light on in the dash is quite a relief after more than a year of constant on.

Regards, Maurice.

[mikeatfhc]

I have the same seatbelt buckle problm as you - without the code 21.

Had the driver's and passenger's buckles replaced but now Duramentric reports code (I believe 48) Driver's seat belt buckle.

I am having a hard time searching for the ground fix. Any pointers?

The write-up would be great.

[Loren]

I have the same seatbelt buckle problm as you - without the code 21.

Had the driver's and passenger's buckles replaced but now Duramentric reports code (I believe 48) Driver's seat belt buckle.

I am having a hard time searching for the ground fix. Any pointers?

The write-up would be great.

The fix is fully documented in a Porsche TSB. All Contributing Members here can read that TSB (online here).

[mikeatfhc]

I have the same seatbelt buckle problm as you - without the code 21.

Had the driver's and passenger's buckles replaced but now Duramentric reports code (I believe 48) Driver's seat belt buckle.

I am having a hard time searching for the ground fix. Any pointers?

The write-up would be great.

The fix is fully documented in a Porsche TSB. All Contributing Members here can read that TSB (online here).

I am a member of ALLDATA and they had not updated the TSB to include the ground fix. I just logged in with them and they now have it. It's probably time I become a contributing member here has I now have two Pcars and have been lurking for quite a while.

My problem is that the previous owner had the belt buckles changed by an independent prior to my purchase of the vehicle thus turning off the air bag light and now I have the light and the driver's belt code. I figure I am going to have to remove the driver's seat and see if the independent actually did the ground point repair as well. Or, try replacing the belt buckle again on my own.

[Loren]

Check the resistance across the good buckle (passenger side) and compare it to the bad buckle (drivers side). The should be very close.

The new buckles have gold contacts so they should almost never need to be replaced again (or at least until you hit 250,000 miles ;) )

[mikeatfhc]

Do you suggest I check the resistance from the metal inside the buckle to say the nut which bolts it the seat? If so will do.

I suspect that the independent who did the work didn't follow the TSB completely and may have just switched the buckles alone, but who knows. One thing I did notice was that my new copy of Durametric would not reset the airbag light at all. I updated the software from the site and have yet to try that to see if I can at least reset the light.

I'll let you know how this goes, now if the rain would stop just for a few minutes...

Thanks for the help.

[Loren]

Checking resistance across the electrical connections should be fine (when buckled).

My Durametric software does reset air bag lights - so I know that should work. (I also have a PST2 and PIWIS if you are ever in my area and need help).

[mikeatfhc]

Ok now I am little confused. How can I check resistance with the buckle engaged? Say one lead on the metal of the male (inserted) end of the buckle while the buckle is engaged and the other lead on the mounting bolt to the seat?

I may take you up on that offer sometime Loren - I have a nasty OEL that has been giving me fits. Countless seaches just bring numerous returns of possible fixes. I am no slouch but I am definately not an OBDII mechanic by any stretch.

I have followed your threads as a lurker for some time - thanks for all you help.

And my sincerest apologies for this hijack!

[Loren]

You disconnect the electrical connector for the buckle and read across that electrical connector. You can try it buckled and unbuckled - as I recall when buckled in changes by about 100 ohms.