Hello All, I know this is a frequent problem with the 964. My 1991 C4 will not pass VA. State inspection with these dash lights on so I am trying to find the most expedient way to kill them.

I have cleaned the air bag sensors but the lights came back on immediately. My good friends at Intersport did attempt to clear the lights...but didn't look at the diagnosis log...and still charged me $100 leaving me with no sense of the problem or fix. I have sprayed and cleaned the seat belt clasps and the driver side connector beneath the seat.

Any other thoughts? the consensus seemed to be the air bag sensors in the front.
Anyone local to Falls Church with a bosch hammer who could help me out?

Thanks
John

1991 Red Carrera 4
Former car was 1982 911SC

 

John, I think the problem is also caused by a bad solder joint on the back side of the clock. I don't know the particulars, but do a quick search and I'm sure you'll find the issue. My car has the same problem but I have a scanner to reset it. I think mine problem is at the sensors since the lights come on when the body flexes.

 

I agree that the likelyhood are cold solder joints on the clock - had the same problem, light resets would last a week or two.

I disassembled the clock and resoldered all of the connections on the boards. That was 3 years ago, and NO LIGHTS SINCE!

 

Also have the airbag light only. But My clock light is out at night. Is this replacable?

 

John, have you posted your query about the hammer to Dorkiphus? (www.dorkiphus.net)

 

Some important notes on this.

Although I have read about this being a problem with dirty connectors in the Air bag sensor or even in the clock, in this case it was a bad Air Bag Sensor. The read-out clearly stated a grounding problem and a circuit problem in the left sensor.

The bad news is that according to the mechanic (my new friends at Autobahn, Fairfax) this sensor is "discontinued". He has initiated a search for a replacement part (say for the 993) or changed part number and has promised to contact me.

The good news, (and why they are my new friends) is that they had a spare used one kicking around and Voila! it worked and I now have a dash free of warning lights and a new inspection sticker. Life is good.

So anyway, if you can get a diagnostic pulled when/if this happens and it reads a bad circuit and bad grounding it is probably speaking the truth and you need to locate a new sensor. It did specify Left vs Right so that was helpful.

The shop was great. When I showed up the owner pulled out the hammer and did a quick diagnosis and that meant a lot to me and was really helpful. Kudos to them for transparency and good customer relations.

 

My Air Bag and Seat Belt lights have come on as well. A year ago, Porsche of Arlington told me that both lights go on together to show that there is a problem with the gauge. Therefore, a cold solder joint within the clock gauge makes sense to me. Mine was cleared with diagnostic a tool and was fine for almost a year. I would be interested in learning what steps LouZ took to take apart his clock and what joints were worked on. It is annoying! Thanks KFB

 

Clock repair DIY here

 

Just what I was looking for. Thanks Dave R.

 

Clock repair DIY here

Yep! That's what I followed with SUCCESS!

 

hmmm...agree the clock is a wildcard. Perhaps the difference is that the error codes would NOT clear. Thus indicating an actual airbag failure vs a failure caused by a slowly deteriorating condition exacerbated by normal driving vibration, eg bad solder joint isystem n the clock.

I think it important to debate these oddities so the next guy has a clean list of troubleshooting steps. I was convinced that the problem was in the airbag system once it was obvious the codes were not going away