Robert Coats

So I’m just driving along in my ’91 C4 with 57k miles and the airbag, seatbelt and master caution (!) lamps all pop on. I use the cancel switch to make the master caution lamp go out, but the airbag and seatbelt lamps stay on.

Next, I do and note the following:

Unfasten my seatbelt, and then fasten it back (no change)

Arrive at my destination, and turn the car off. As I do, I catch a glimpse of the BATTERY warning light as it briefly flashes when I shut the car off. Hmmmmm. I never noticed that before. Maybe it’s a clue as to why my airbag and seatbelt lamps won’t go out? Let’s try again.

Sure enough, I restart the car, the airbag and seatbelt lights are steady, and, as soon I as I shut off the car, I see the BATTERY lamp flash, just for half-second or so.

Question #1: Does your BATTERY lamp flash briefly when you turn the car off?

Question #2 What would cause the airbag AND seatbelt lights to stay lit?

Question #3 Any troubleshooting ideas or places/things to check to solve this puzzle?

Question/theory….I have a hunch the battery may be dying. The car starts just fine, but the brief flash of the battery lamp at shut off doesn’t seem right. Maybe the seatbelt/airbag circuit senses the battery isn’t 100%, and that’s why they are staying on? Maybe the brief flash of the battery light indicates the battery is starting to die?

Finally, it's been very hot an humid here in Atlanta this week, and I know heat will kill a battery faster than cold. Barring any suggestions from you folks, I'll take the car in to have the battery tested and see what I get.

Jay H

Robert:

My battery light does not flash when I shut my car off.

If I remember correctly, Porsche released a TSB having to do with a faulty clock that made the seat belt and air bag lights come on for 'no good reason'. A search of the archieves may shed some more light on this. (This may or may not be your problem.)

Resetting the lights with the hammer helps initially, but the faulty clock circuitry makes them come on again. Also, I would assume a scan of the codes with a hammer would reveal the source of the error.

Good Luck,
Jay
90 964

FlyYellow

I had/have the same problem on my car. The hammer code signified that the passenger side airbag crash sensor was faulty. I had it replaced and 2 months later it went back on. So I'm having the dealer replace it again.

My experience in warning lights is the same as you described. I'm starting to wonder that if my stiff suspension doesn't cause these sensors to produce a fault code.

Cheers,

Boris

Randall G.

Hi Robert,

My car had the same problem, pretty much as Jay described. Besides the airbag and seat-belt lights, I also saw the battery light intermittently. Had the lights reset twice before replacing the clock, the lights came back on a short while later.

Since replacing the clock (3 years ago), all has been fine.