No start, Crazy story, not normal "key error" message
 

This will be a decently long post just a heads up, new to this forum and volvos but not cars AT ALL. I've ran shops for the last 13 years, im not an automotive genius but I'm far from car dumb... on to this ridiculous story of my VERY FIRST VOLVO...

So I purchased this car knowing it had a "sleight" starting problem. Did my research and wanted a C30 for a few years now so pulled the trigger being confident I could fix it quickly and get this car half priced...BOY WAS I WRONG. So when I bought it it ran great, still does, but would throw the " KEY ERROR" message once or twice a day. After a week, it went downhill fast, only starting after battery unhooked for 1-3 days, so I replaced the SCU and it did nothing, took the ECU off, cleaned connections not that it looked like it needed it and put back in. Took CEM out, no corrosion, took board out of casing, no corrosion, cleaned all anyways and out back. Still nothing. Took it to the dealer and now after a month I have it back, this fixed nothing and was a waste of time. At first they thought it was the SCL and replaced it, nothing. Spent 3 weeks messing with it to just be stumped the whole time, stating there was no communication between CEM and ECU, software update did nothing. Then one day they put a battery charger on it and it started a few times, mind you battery was tested by me and them a dozen times and is putting out over 12v. After that it lost comm again and asked for 7 hrs of wiring diag time. After another week, they again were nowhere and the tech bumped the dangling SCU with his hand and it starter up, several times for 2 days. Again, then back to nothing. So I brought it back to me (my shop) and it seems to be starting randomly, few times throughout the morning but not afternoon, and I am so frustrated its not even funny, I'm ready to give up but I do not want to its a fun car, exactly what I wanted, im reaching out for help, someone please help me lol. Thanks in advance.

P.S. quick recap...battery good, Cleaned CEM and ECU. Replaced SCL and SCU... about to give up...Also will throw random SCL error but once every few days...

As a Volvo shop owner/tech for 40 years - I've heard stories like this many times. And now you know why the car was for sale. You can mess with it for XXXXX time not sure when it will start so you can take your wife/girlfriend/partner out in a nice car for a nice evening - OR -you can sell it to the next sucker and find a different car that will be fixable. Some cars can't be fixed.

If it's your toy, your hobby or challenge - you can try - but the if people with the factory equipment and training can't fix it - you won't find the answer here or on sweedespeed.

I'm aware this is crazy weird and will be a weird challenge, but from what I can tell the dealer didn't really do all they tried to get me approved, almost zero wiring got looked at, a few parts were thrown at it, and the month it was there they looked at it a handful of times. Not a huge dealership and zero confidence coming out of there... but you're not wrong, it probably would be best to turn tail but I can't do to someone else what has been done to me here. It's not ok, as I've watched this for years running shops, I can't be the one responsible for that. I'm hoping for another crazy case and someone read it but we will see, either way like I said, its looking like that's gonna happen if I can't find any wiring faults in the next week or so. Thanks bud...