I have an Opel Frontera 1999 2.2 Diesel. It refused to turn over a couple of years ago and it's taken me this long to get to doing anything about it. I was advised that it was something wrong with the key/immobiliser so the garage replaced it with a secondhand system consisting of ECU, Immobiliser, Ignition, Key, Key card reader ( i think it was called) and RCL controller ( not sure if that one was used or not in the end).
The garage ( who I trust and I also think they are very competent) said that they tried everything but couldn't get the jeep to turn over. The main problem was they couldn't do any troubleshooting because they couldn't get the diagnostics unit to connect with either ECU - ie the old one or the new one. The suspicion was that there was some issue with the wiring loom. Does this sound plausible? It does to me I suppose especially because the problem was originally intermittent and it ultimately took a few months to break completely. If it does then I think I will elect to scrap the car because it just seems like it might not be the end of the line with the repairs, but I just wanted to ask here in case there might be something else obvious that we were missing.