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Electrical problem - engine computer relay/fuse box short and burnout
I wonder if others have had a problem like this: I drove my car to work as usual yesterday, noticed nothing out of the ordinary. But when I came out to drive home at about 6:15 pm, the car wouldn't start -- engine cranked over easily, all electrical systems seemed operational, etc., but the engine just wouldn't catch and start up. I turned it off, let it sit for at least 10 minutes, tried again (several times) - no luck. I eventually had it towed (via flatbed) to the local dealer. They just called to say that the engine computer relay and fuse box had shorted and burned out. Projected cost: $650 for parts and labor, and it will take a couple of days to get everything together and fixed.
Does anybody know whether this is a common problem on 993s? Is there anything I could do (or should have done) to prevent it? Or is it just one of those things that sometimes happen to a car and I should not worry about it?
Not a mechanic here, but that sounds like the DME relay went bad. Which by the way is a common problem. As far as burning and shorting out I have not heard of that. If that has happened others will chime in. IIRC a DME is only 28.00 USD. Many P-car owners cary a spare DME relay in the glove box.
I concur with my buddy. I think you're being taken for a ride.
The DME relay (failing) causes these EXACT symptoms. You can get them on ebay for around 20 bucks or so. $tealerships will charge in the 30's.
If they haven't done anything to your car I would GO THERE NOW and take a look at the fuse/relay box (just under the carpet/mat on the passenger side). if there's no "melted disaster" when u lift off the cover then you know you're being stiffed. Go to the parts dept. get a new relay, put it in yourself and never go back to that $tealership again.
And carry a spare with you!
Originally Posted by danpugh
I wonder if others have had a problem like this: I drove my car to work as usual yesterday, noticed nothing out of the ordinary. But when I came out to drive home at about 6:15 pm, the car wouldn't start -- engine cranked over easily, all electrical systems seemed operational, etc., but the engine just wouldn't catch and start up. I turned it off, let it sit for at least 10 minutes, tried again (several times) - no luck. I eventually had it towed (via flatbed) to the local dealer. They just called to say that the engine computer relay and fuse box had shorted and burned out. Projected cost: $650 for parts and labor, and it will take a couple of days to get everything together and fixed.
Does anybody know whether this is a common problem on 993s? Is there anything I could do (or should have done) to prevent it? Or is it just one of those things that sometimes happen to a car and I should not worry about it?
To close the loop on this -- I went to Rockville Porsche/Audi in Rockville, Maryland, which I have used one other time for brake system work. I think they do a good job, though to be honest I have no real basis for comparison. Although they are expensive, I presume this is true of all dealer repair shops.
I picked up the car this morning, and the problem seems to have been exactly as they diagnosed -- the DME relay had burned out, and had managed to do so in such a way that it burned a hole in the fuse plate/box (or whatever the connection panel is called) at the point where the relay connects to the box. The repair technicians gave me the burned out relay and fuse box, and it is apparent even to my uneducated eye that it is quite damaged - the melted plastic and hole on the fuse box are about the size of a nickel or a quarter, and the relay has a darkly scored spot near one of its electrical prongs.
My theory is that I didn't smell anything because it probably happened while I was driving, such that the smell had largely dissipated by the time I parked and shut off the engine. Returning a few hours later to drive home, the damage had been done and the engine computer would not let the engine start even though the starter and all other electrical systems were still operational. I'd be interested in others' thoughts on whether such a scenario could occur.
In any event, thanks to all for your input and interest. The car seems to be driving just fine now. She seems happy with her nice new $700 fuse box and DME relay. My next mission is to do as several have suggested and obtain a backup DME relay (and learn how to install it) in case the relay fails again in some future year, hopefully without also damaging the fuse box...
My next mission is to do as several have suggested and obtain a backup DME relay (and learn how to install it)
It takes longer to open the hood and remove the fuse box cover than replacing the DME. It is a simple plug and go relay. Sucks you burned out the panel. Do yourself a favor and keep an extra in the glove box. They never fail at a good time as you can attest to. have a good one and glad to see you back on the road.
Just for curiosity, was the burnt DME relay part# starting with 944... or 993...? I am still running on the 944... but carrying the 993... in the glove box. Maybe I should switch to the 993... and keep the 944... as a spare, just in case.
Just for curiosity, was the burnt DME relay part# starting with 944... or 993...? I am still running on the 944... but carrying the 993... in the glove box. Maybe I should switch to the 993... and keep the 944... as a spare, just in case.
That's EXACTLY what I did! ..."944" part no. delegated to the glovebox !!! --- '993' in the '993'.
Assuming I'm looking at the correct number, the part number on the burned-out relay is:
993.615.227.00
I'm guessing it is pin number 4 that burned out so spectacularly, if that is of interest to anyone (the number itself is obscured by carbon or melted plastic, but I'm inferring the number from the remaining visible pattern). No other pin seems to have been affected.
As I'm the fourth owner of this car, I don't know whether this relay is original or if it may have been replaced at some point in the past.
Also, to confirm what several have stated about the approximate price of this part, by coincidence I received my latest Performance Products catalog in the mail today, and they offer this relay (page 169) at a price of $24.95. I plan to inlude it in my next order.
I had this issue today on my 96 4s, but noticed someone installed a made in China relay (I just purchased this car, was one of Rudy’s, a reseller bought it at auction in Amelia & I picked it up from them a month later, they claim to have changed a window switch once I pressed why they took 12 days to release the car to me). Installed the correct part but the damage was done. even though car is running fine I’m changing the box or at the least taking it apart today as there was
melted plastic on the box. Bummer… but at least the car was in my garage so out of pocket was light. Also this part has gone up to around $75 for same day local purchase in LA.
11-03-2006, 03:53 PM
Electrical problem - engine computer relay/fuse box short and burnout
Projected cost: $650 for parts and labor, and it will take a couple of days to get everything together and fixed. 
...don't even think the engine will turn over
