Chuck W.

The battery was a Red Top and over three years old, so I wasn't too shocked when I came out to a dead battery Tuesday. I replaced the battery and all appeared fine. However, when I went to start it I noticed no immobilizer light on the dash and when I hit the remote the red lights on the door did not flash. I tried several DIY things including the manual activation of the immobilizer and putting in the spare DME and trying another remote. Still no immobilizer lights.

Any ideas before I tow it to the shop? TIA

95 C4 993

Replace the battery in the immobilzer. Then buy 2 extra batteries and put them in your car with a small phillips screwdriver.

95 C4 993

I have been down this road a couple of times and low and behold, I had bad batteries in both immobilizers. Not saying its the answer but its worth a shot.

geolab

What kind of battery did you get? is it a porsche battery?
If so, in the EU the porsche batteries come uncharged and you have to charge them.
Check if the new battery is charged, if its a porsche one.

Slow Guy

I don't think this is a Immobilizer Remote problem.

Was the battery fully charged when you installed it? I would suspect that the battery cables are not making full connections. I don't THINK the DME relay would behave like this but I'm not certain.

Also, could there be a fuse/relay for the immobilizer itself?

Randy 1

Call me crazy, but isn't there a code inputted by turning the key on and off? I remember I was having the same problem after the car had sit for 3-4 years, even with a fresh battery. I had a friend come over, and I hazily remember some sort of fancy code using the key...

edit: ah ha, I assume that's what "manual activation of the immobilizer". Well, then, I'm stumped.

Chuck W.

I bought another Red Top and put it on the charger all night. Everything in the car powers up strong. The battery if fine. I just checked both remote batteries and they both were strong.

geolab

Now that you have the workshop manual, please refer to page 1456 to 1481 alarm system diagnosis.
there is a step by step diagram, I am sure your answer is in there

95 C4 993

Mine is a 4 digit code. What the hell, give mine a shot

Immobilizer Code 3688

Chuck W.

Good point....I'll see if I (a non-tech) can figure it out.

Chuck W.

Hah,,,,great stuff. But not enough for me to figure this out.

Chuck W.

OK....I go out and reconnect the battery....The car starts.....I pull 5 feet forward and it dies. Again, no immobilizer light. Try the battery disconnect several times during the day and the last time the immobilizer light comes on and the car fires up.

I figured it out. There is a problem I can't solve so it'll get towed in next week.

I will post what the problem was.

Slow Guy

Chuck, did this get resolved? What was the cause? IMWTK

Chuck W.

I wish...My machanic is busy and can't see it until the end of this week or the first of next week. I'll post the problem when he figures it out.

24FPS

love it if there's a reply or another thread with what solved Chuck's problemo.

had similar issue with my cab & a new DME seemed to solve. but I'm also looking into installing new ground straps off battery & starter. prob was intermittent for me.

new battery & alternator... THEN 3rd DME worked until a snafu today.

993 cab will go to Indy ASAP.