HELP Airbag Light...The dealer says bad Alternator

[DCinVA]

Could it be true?

My airbag light came on the other day, and after a bunch of research here on pelican and the other usual sources, It looks like the most probable cause is the seatbelt buckle. So I cleaned all the electrical connections, and took it to my local Porsche dealer to read out the codes, fix the issue, and reset the fault.

The dealer tells me that the reason the airbag light is on is because the alternator is not putting out enough voltage, and the battery might have a shorted cell as well.

Now..... I am not saying they are wrong, but this does not really make much sense to me. It is like going in with a flat tire, and having them tell you the fan belt is at fault.

Can anyone out there help make some sense of this? Is this really possible? I am well versed in repairing cars, and with the help of everyone here I do most of my own work, and only farm out the things that are way over my head, or things that I really don't want to mess with, or in this case, things that require a special integration tool to read and reset fault codes.

Oh, and in addition the total cost to repair is $2,000 + , and the alternator alone is $1,000.

Any advise would be very helpful.

In distress

Dave

[nosnow4pc]

Did they give you the airbag fault code? It should have come up with something, that would be helpful for the more knowledgable members to see if what they say makes sense.

As for the alt and battery if you are versed in car repair take the alt out and have a local shop rebuild it for a fraction of the cost. I bought a Napa battery for less than $100.00

[DCinVA]

I had a very brief conversation with the service rep while I was eating lunch with friends. I called him back and left a message asking the following 3 questions.

1) Is the alternator and battery problem related to the Airbag light? (I took the car in for Airbag Light, they told me I needed an alternator, I guess I am not convinced the alternator is related to the Airbag Light)

2) What was the airbag fault code from the computer?

3) Were you able to reset the fault code for the Airbag?


Two hours later no reply from the service rep.

Frankly I am not sure whats going on. The dealer communication is pretty poor. Sometimes service reps treat customers like idiots, without realizing that many of us are probably more knowledgable about the cars than they are.

[DCinVA]

Thanks for replys. Here is the latest, and hopefully the end of this issue.

I spoke with the service rep, and the code from the ACU was "Insufficient Power Supply". This is probably due to the fact that the car is not driven often, and has had the battery go dead several times over the past year. The dealer was able to clear the code from the ACU, and the rep finally conceded that the car would probably be fine if I were to drive it more often. So it appears that perhaps I do not need to replace the alternator after all. The really good news is that they decided to not charge me for the diagnosis, and clearing the code.

So the answer to my initial question is "YES", a low battery, or bad alternator can cause the airbag light to come on.

I think it might be a good move to invest in a tool to read the fault codes.

[mcmike27]

A good idea is also a battery tender from Porsche $100.00 (when the car is not being drive for extended periods) and a inexpensive battery load tester to see if after it's been fully charged is still up to snuff...if not a new battery is in order.

[dad911]

Time to find a good independent shop.

[Zeke]

Not good if your car has had a low battery several times and you drove it to charge the battery. alternators are not designed to charge a very low battery, only maintain it.

You may still need an alternator. Why not have the output checked?

[Wayne 962]

Terrible example of a dealer trying to rip people off. They probably recognized that you were smarter than they thought and decided not to charge you in the end.

-Wayne

[DCinVA]

My saga continues.

I pulled the alternator today, I must say it is not a job for the timid. Pulled the battery as well. Alternator tested at 130 amps and 14.4 volts. That is good. Had the battery tested as well, and it checks OK. I did buy a new battery as a precaution.

I Re-Installed the alternator, and the new battery, and before I put the car back together I tested the voltage with the car running. Everything is in spec. I buttoned it up and went for a ride. After about 20 minutes, the battery light came on (and I think I may have said a bad word). Luckily I was not far from home. I pulled into the garage hooked up my voltmeter, and the alternator is not charging at all.

I think I am going to make a very stong cocktail.

This is an interesting article which may help explain my alternator issues.
http://forums.pelicanparts.com/porsche-996-997-forum/408495-alternator-repair-regulator-replacement.html

Thank god we have this board to help us sort out these wierd issues.

[DCinVA]

End of story...

So it turns out that the alternator charges fine when the engine is cold, but as the engine warms up, it fails to put out enough voltage to keep the electrical systems happy.

I called our friends here at Pelican, and had them overnight a rebuilt alternator to me. I placed the order at 5:30PM EST (I live in Va), and the alternator arrived the following day at 1:00PM EST. Thanks go out to Darren, who rushed my order to the shipping area to make the overnight deadline.

I installed the rebuilt unit in under an hour, it is much easier the second time around. Now the charging system is putting out 14.4 volts, which is the high end of the acceptable range, and it even charges at that level when the engine is warm.

The final chapter...

The new owner picked it up last night, and he is extremely happy with the car. He called me when he got home to tell me how much fun he had driving it home !!

I will truly miss this car, but it is time to focus on other things.

Dave

[Zeke]

Well, I guess your dealer wasn't so much of a rip off after all. Glad you had the perseverance to find the problem.

[stinson]

thanks everyone for good info. I am just starting this quest as my air bag light just came on. So, is the short answer to clean the contacts on the seat belt before attacking the alternator?

[paulv]

Originally Posted by dad911

Time to find a good independent shop.

Ain't that the truth!!!

I always worry about people's stories about how a dealer "thinks" what the problem is -- I would expect a dealer to have a definitive answer considering what they charge!!

Regards,
paul...

[Zeke]

Originally Posted by stinson

thanks everyone for good info. I am just starting this quest as my air bag light just came on. So, is the short answer to clean the contacts on the seat belt before attacking the alternator?

Worked for me. I used distilled water and distilled vinegar followed by electronic contact cleaner. I suspected water soluble dirt or some food substance. The contact cleaner was to get rid of any oily type of contaminate. Clean compressed air helped.

OK now for a year.

[stinson]

My 97 Boxter has an airbag light on. I bought an OBD2 reader today and it says all systems are good. How can this be?

[paulv]

Originally Posted by stinson

My 97 Boxter has an airbag light on. I bought an OBD2 reader today and it says all [emission]systems are good. How can this be?

Regards,
paul...

[pogo]

"Originally Posted by stinson
My 97 Boxter has an airbag light on. I bought an OBD2 reader today and it says all [emission]systems are good. How can this be?"

The airbag code is a "manufacturer specific" code. Your OBD2 scanner only knows generic codes. There is a Porsche scanner that reads the codes unique to Porsche, which I understand is far more expensive.

[johnsjmc]

A dead battery can indeed trip the airbag light. I let mine run down parked too long with the radio and other accessories on . The car cranked slowly and then wouldn,t start. After a recharge it starts fine but the airbag light is on. I had it reset at an Indy with their generic scan tool(Autel brand or something like that?). It has stayed off .

[Luccia at Pelican Parts]

We have some great diagnostic scanners HERE as well and some that can turn off the airbag light. We use the AutoEnginuity tool on a lot of our in house projects.