ducnine

I have the airbag/seatbelt light on my new-to-me 90 964. According to the owners manual, the airbags should have been checked out at 10yrs and then every 2yrs after.

*What is the dealer doing when the "Check" the airbags?

*When you do the clock mod or make your own "hammer" as I have seen in some other threads, are you just cheating the system so the light won't go on?

*DOes this require changing the airbags out? Cost?

LouZ

When you have the airbag AND seatbelt lights, it's a good bet that the clock circuit was either disconnected while the battery was connected, or the clock circuit board has "cold"solder joint(s). It appears that you have read the threads about repairing the circuit board on the clock. This does not CHEAT the system, it fixes an intermittent fault that triggered the lights.

The debate is still ongoing on the true life expectancy of the actual airbag, it is 16 years old. (I'm not concerned,others may have a different feeling). The hand-built "hammer" will turn off the fault code and reset the lights after the circuit board fix.

dfinnegan

There seem to be two common problems with the airbag and seat belt lights. One has to do with the connections to the crash sensors in the front trunk. Cleaning them can sometimes cure the light problem.

The second has to do with the cold solder joints on the back of the clock. These sometimes need to be resoldered. See this site for a write-up of the procedure.

As for the Hammer, it can be used to reset the fault so that the lights go out. It is likely that they will come back on, but it could be a day, month or year.

I'm not sure if the home made hammer can reset the airbag fault. See this thread for a start toward understanding the home made software.

Cheers,
Dave

JasonAndreas

The first thing they do is check the airbag warning lamp by turning on the ignition. The light should stay illuminated for ~5 seconds for MY89-91 and ~2.5 seconds for MY92+. If the lamp is dim they check the bulb and the supply voltage. The next thing to do is remove the fuse for the "instrument voltage supply" (i.e. clock fuse) for ~30 seconds with the ignition turned on. You then read off the error codes from the airbag control unit looking for, "warning lamp: short to Ub or ground, error not present". Then you plug the fuse back in and clear the fault codes. The dealer is also supposed to check for covers, stickers, etc. covering the airbags on the steering wheel and on the passenger side.

No, the clock mod just reduces the current draw on the battery by removing the warning lamp for the convertible top. With the DIY hammer all you're doing is erasing the fault code. If the fault still exists the code (and warning lamp) will return.

No it doesn't involve removing the airbags and you shouldn't be charged for more than 15 minutes. The most time consumning part of this is waiting for the Bosch Hammer to interrogate the control units and figure out what is connected to the car.

FotoVeloce

Hm.. this is good info. I've had both illuminated on my car since I got it, was not a big worry to me as I always have my belt and I don't care about a 16 year old airbag (in fact I'd rather remove it).

So, if I have the lights due to a battery disconnect then the bags are likely to be OK and all I need to do is get ahold of a scanner and clear it? I'm afraid to ask how much those Bosch Hammer's go for... would a Sear's 10lb mallet do the work just as well?

Sorry.. but seriously it sounds like 'The Hammer' is the right tool for the job. How many thousands do they charge for those? :/

LouZ

AS a point of clarification, I got my 90 C2 and the lights were on. I had the car Hammered, an dthe code was reset and the lights were out.....for a week!

I "built" the Hammer (from ECUFix) and checked the faults, then erased the code and, again the lights went out....for a couple of days. Finally, I pulled the clock out and disassembled the circuit board and resoldered all of the connections, reassembled the clock, reinstalled, reset the codes with the hammer and.................................to date, NO LIGHTS!!!!!!!!!!

dfinnegan

The Bosch Hammer (KTS 301) is only available used and they run approx $1800; last time I looked.

The home made hammer referenced above is free; except for parts, of course.

Zedmau5

i have a similar problem with my 951... the airbag and seatbelt lights are on.

Its going in the shop tomorrow to have that problem looked at... how much will they charge me for a fix?

FotoVeloce

As much as I prefer to have the 'real-deal' tools... I think I can justify a variance in favor of some new set of wheels and some slicks...

wow.. that's not cheap!!

ducnine

So does this mean that the light does not come on at all...even at start up?
Or it comes on for a few seconds at start up and then goes away like it should?

last toy

The seatbelt comes on as a pre-caution when the air bag light stays on. I was told Porsche designed the system that way to remind the owner that the airbag might not deploy so make sure the seat belt is engaged. i would clean the front contacts first before re- solderimg the circuit board. I understand thta once you solder one contact, you might have to solder all of the contacts because they get brittle. I went to a Porsche dealer when mine came on when I was out of town and it cost me $200 for them to tell me I need new seat belt receptacles and air bag system components, etc. What a joke. I went to my Porsche shop at home and they cleaned the contacts and reset the codes for a few bucks.

bigchillcar

i installed a new stereo last night and negelected to disconnect the neagtive terminal at the battery during the install, which i read later i was supposed to do. it was a huge job installing the new stereo as an unbelievable amount of old wiring had to be removed. now i have a great working stereo, but i've got three warning lights: first the 'airbag' and then the 'seatbelt', which i just read comes on auomatically if the 'airbag' light is triggered. okay. i also have the convertible top light on?? i had the top down during the install..not sure if this has anything to do with it. my fear is that i may have inadvertently cut something important during the removal of all the old wiring, which included amps, etc. in the front trunk, old front/rear radar detector components and even some kind of fancy hands free phone system with mic stuff on the steering wheel. i'm going to try and recycle the top for that. for the other stuff, i'm stuck..looks like i'll have to find an exotic car shop, as there's no porsche dealer in arkansas..
ryan