how to change a ecu on an AUDI A6 Quattro

The ECU is inside a black plastic box, which is screwed onto the frame of the car inside the area where the battery and brake fluid resevoir are located. This area, which is under the under, has a plastic cover over top of it which must first be removed. Once you have located the ECU weatherproof housing, remove the 3 or 4 screws that hold the cover on - very easy to do. Once removed, you can identify the ECU easily inside the box. There a screws holding this down as well as it being plugged in. Remove all of these attachments and replace the unit with your new one. Reverse these steps to finish the job. Done!

Great answer and Thank You for Your time. Is this information, however, accurate for the 1997 AFC engine? I am dealing with a no start after a battery drain. I am dealing with no spark to My ignition coils as well as No fuel to injectors, however I have fuel to the rail and the filter. Very confused. I'm looking for an open or a double ground anywhere and believe it could be the relationship between ECU and ECM however I'm not sure. I'm rebuilding after a head gasket job. I checked timing but not confident it's there and I'm hearing the car want to turn over but no spark or fuel. I'd like to think this was electrical as I'd done near a dozen timing belt changes on these cars. Please help!