Phantom Problem....engine immobilizer
 

My 04 8 has 20000 miles on it. Within the past two months my engine immobilizer will trip and shut everything down. First it started when i would come out of the grocery store or something and car wouldnt start. Key light flashing (engine immobilizer). Now it does it while im driving 65 down the interstate. It shuts everything down. Dealership ran diag., had communication errors, but couldnt find a source. Has a new ecu. No loose grounds. They were on the phone with tech support for hours trying to figure it out. anyone have any other ideas. They said it might be the fuse box is bad, but i dont want to spend $600+ because it "might" solve the problem. HELP!!!!!

This may sound stupid....Have you tried using a different key for awhile?

Make sure you don't have other ID chip keys on your keyring - they can confuse the pickup.

S

Yeah that was the first thing i tried. Thanks though. Dealer cant seem to find where the communication errors are coming from.

Well it is not engine immobilizer....rb race flash deletes immobilizer. Really lost now. Stalls while driving, cant restart. Wont turn over. Disconnect battery to reset pcm. Starts right up. No idea what to check now. What would shut everything down and have to reset pcm to start back up???? New pcm already installed!!!!

As easy as this sounds, i have this same problem right now..after swapping harnesses three times (yes the entire car wiring harness) it looks like the original harness had a main fuse melted to shit. It would still start if i reset or let it sit overnight and drive for about 10 minutes or however long the battery would last. BUT not sure how long that fuse has been blown or if that was the problem

So did rewiring, fuse fix the problem?