first time posting so excuse any mistakes, but i'm out of ideas and could really use some help.

First things first: got my new car early 2018 and it seemed perfect! My very first drive was the drive home (~ 1800km). It all went perfect.

Skip ahead to the start of 2018 winter. While parking, switched into R and the whole care shook a bit and then all warning messages started popping up in the hud. Check engine, Brake system, parking, pedestrian collision system, you name it. Ofc, i panicked and called my mechanic. Being an IT person i laughed when he told me to turn it off and on again, but i did it and i worked. The check engine light remained but the car was operating normally. Turns out, after measuring, the battery was barely holding a 18% charge so we switched that and all was well...

Every now and then after changing gears (leaving a parking spot or just picking someone up) the car would shake a bit when pressing the accelerator in D (think of a manual transmission when you press the accelerator too fast and release the clutch -sort of a mini burnout) but that happened like maybe once per month, if even that and the guy i'm working with on it now says it was most likely because the oil in the transmission was quite old.

Fast forward to November 2019, had a bit of a road-trip and google thought a freaking animal path was a road and this happened:


I managed to pull the car out with the help of some nice people but afterwards i could not drive faster than 65-70kmh. The steering would shake and the trepidation did not feel good. Found a nice guy with a water hose and did my best to get the mud out from the wheels and anywhere else i could find any. Still the same. Got home, eventually, went into a car wash and had the underside cleaned. Still the same. Drove to my mechanic, he cleaned it as well, took wheels off and all the shaking finally went away.

A few weeks later the whole dash board lit up again, like the first time and i drove it back to the mechanic. He took it to a electrician who kept it for about a month. Car went back to the mechanic for testing and then to me with the message "we fixed it!" They did not...

At this point i should point out there is no authorized dealership or service point for Volvo in my town, the closest is a 3 hour drive and now, when the warning lights went on the car would enter "limp mode" and would not switch out of gear 3 unless stopped and then only into R.

The electrician i mentioned earlier worked at a bigger dealership that bought the rights to open a Volvo dealership and said he'd take it in to his workplace where his colleagues were currently being trained. Not much could be done, the trainers could/would not touch the car but did suggest that a cable harness/bundle between the transmission and TCM should be checked. He checked, fixed it and returned the car, but, as you can guess the problem reappeared.

At this point i gave up on my mechanic and electrician and started asking around. Found a guy that used to work at the Volvo dealership (before it closed a few years back) and now had his own shop. Guy seems great and knowledgeable, i spent a few good hours with him in his shop today trying to figure it out, no luck.

If you are familiar with the VIDA car diagnostics SW, here are some photos of what it reports:
(ignore the time stamp, it's because the laptop he uses hat the clock set back/wrong etc)



After bashing our heads against all the walls we decided that since every module seems to lose connectivity to the ECM we should take a look at it. Even though its not that easy to get at (behind a wheel well and in a plastic casing) it looked "weird"



notice the top left corner of the unit

Almost as if water got to it and corroded it. The cables themselves seemed fine but we started to think the ECM had water damage




Its not really visible in the pic but the 2 pieces of the housing seemed to have a strong glue (black silicone?) keeping them together. It goes all the way around and opening it might have meant we had to heat it up, who knows how much and who knows what more damage we might end up causing. We decided against it.

After putting it all back together the error messages kept showing up. The first module to report errors seemed to be the PAM (parking assist module). We went to the back and checked:




no idea what the green connector is for, does not fit anywhere -maybe some option i don't have equipped?

All was dry, all looked well. Another dead end.

Now we literally have no idea what else to check. The PAC was in pristine shape, no sign of any short circuit or water damage or anything.

Still:


Resetting/Erasing the errors resulted in:




At this point, any ideas/suggestions are welcome.

Thanks in advance.