986 Alternator issue. Non Starter, ECU not found
 

Hi All,

I'm a long time reader, but first time poster. I've hit a bit of a wall (metaphorically, thankfully) with my 2000 2.7 Manual 986.

I've just had a few things go on the car - it's high miles (180K) and it's in use most days. New clutch, new Dual Mass, a pre-cat O2 sensor and a new battery all in short succession. Then the alternator shuffled off this mortal coil. I'd driven for about 2 hours, stopped for snacks and then couldn't restart without a jump. So I replaced the alternator with a used one that I had lying around - just to get by and check that there were no other gremlins in the system. 70 miles later, after driving for about 90 minutes, the car seemed to stall as I slowed from 60 to 20 in a queue of traffic. I tried the key and nothing. As I was still rolling, I tried to bump and again nothing. So I pulled up and noticed an electrical burning smell from the area behind the drivers seat, so I assumed the alternator was toast. I checked some fuses, the battery (13V) and I was fortunately very close to a garage who tried a starter/boost pack on it which had the same result. Ultimately had to just scratch my head and finish my journey on the back of a recovery truck.

The car doesn't even try to crank. The ignition switch lights up the dash but does nothing after that. I connected my generic OBDII reader, which has worked in the past and still works on my other cars, and it can't find the ECU.

I've recharged the battery fully - nothing.
I've checked every fuse - nothing.
I've had the alarm/immobiliser out to check for water damage (as I've had this before with the car, but magically survived a good drying out!) - nothing. (remote opens and locks etc)
Swapped the alternator back and checked all the cables for scorching etc - nothing.
I've taken the ECU out of the rear trunk and had a look inside and that all seems pristine too - no burning or scorching etc.

I've just bought an ignition switch as I know these can be tricksy, so I'll try that when it arrives, but I don't think it'll do anything for me as it seems a further along kind of problem to my (non) expert eye since the ECU isn't being found.

All in all, I'm a bit flummoxed. Has anybody had this or anything like it and/or can an anybody offer a suggestion for something to try that I've missed?

Many thanks!

Steve