Help - car has died.... ECU ??

Hi all,
Travelling along this morning and the oil level light popped on. So I stopped,topped up the oil but the light remained on. Definitely enough oil as read on the dipstick so thinking a faulty sensor I continued on my journey. About 20 miles later in traffic, just shunting at low speed and the car suddenly died. When attempting to restart it I had all the gears ( D,R,1,2,3,4 etc ) all lit up red. Engine management light and abs light also permanently on, it turns over but won't fire up. Just had fault codes read and the gearbox is saying missing command from ECU, Engine says missing command from ECU and any attempts to connect to the ECU directly fail ?? I've been told by a local garage that an ECU fault is plausible.
Does a faulty component on the ECU seem likely ?? After my alarm horn exploits I'm quite keen to try to repair it myself as I've heard there can be problems with drains blocking and water getting in there, does this all seem plausible to you knowledgable bods ??
Worst case scenario I understand I'm looking at the best part of 1K to get a new one and I've seen some A8 ECU's on A8parts - Does anyone know if these are different units or are they just generic ECU's flashed with a different program ??
any help/advice from you chaps is much appeciated as I'm feeling really deflated now and IF there is a good time for car problems it certainly isn't 2 bloody weeks before xmas
Help ....

[ainarssems]

If You cannot connect to ECU then it sounds like ECU or wiring/power problem. Which car is it? I have spare ECU for PF S8 AHC engine. I can also adapt immobilizer to accept new ECU if You are local.

Its a 2000 facelift S8... can't remember the engine code off hand.
I'm guessing the drain plugs have been blocked earlier in the cars life resulting in water getting at the ECU. Its annoying cos I'm really on the ball at keeping them clear since I've had it.
Whilst waiting for recovery it did start on one occasion,ran for about 5 seconds then died again. With my electronic mind that just shouts dry solder joint to me, some kind of intermittent contact. My garage are going to get it out and try rebooting/reprogramming it but if that fails I'll have a look myself and see if there's any obvious pcb damage/dry joints/blown components etc
Cheers for the offer tho mate - You wouldn't happen to know if the ECU is different between models then would you ?, Would there be a difference between the FL A8 4.2 ECU and the FL S8 4.2 ECU ??

[Conan_the_Librarian]

Originally Posted by daz.g

You wouldn't happen to know if the ECU is different between models then would you ?, Would there be a difference between the FL A8 4.2 ECU and the FL S8 4.2 ECU ??

Yes, there are lots of different models of ECU out there. There will be a part number on it if you give me that I can find any alternatives for you.

I've left the car with a garage so can't get to it to read the code - will it not be the same for any other 2000 FL S8 ?

[Conan_the_Librarian]

I have found 5 ECUs for the AQH and 9 for the AVP engine you might have in a 2000 FL S8.