Hi!

Posting here, not the english section, but please feel free to write back på norsk! Hoping someone here has some good tips on what either I could try, alternatively where I could take the car that knows electronics (Oslo/Asker area).

Have a 2007 V50 1,6 diesel that has been going into "limp home" mode for ever (won't go over 2,9k rpm). In the beginning simply turning the engine off/on would normally resolve the issue. It usually occurred on warmer days. When the issue got worse, it would sometimes go away when the weather turned cold. No error msg comes up in the display.

When it started at around 116k km, the local Bilia verksted claimed it needed the 120k service (including new DFP filter). This seemed to fix the problem, for a few months. When it came back, Bilia claimed it was an "intermittent" alternator ("dynamo") issue, that was causing multiple faults due to low voltage. This also seemed to fix the problem, for a few months. Last trip to Bilia they simply cleaned the battery terminals, which fixed the problem all the way to the nearest grocery store.

At this point discouraged, I bought a scanner and started checking error codes myself. Thought I found the likely culprit based on the error msgs, and replaced the
MAF
sensor from Volvo. No luck (though it continues to have an error code on the
MAF
sensor). Then this winter, it developed a new problem where it would give a "traction control" error. This would cause the car to run at 1,5 rpm & not respond to the accelerator pedal. There were two error codes on the pedal. Bought a new one and replaced it, problem went away - for a couple months.

Took it to a new mechanic, who spent 4-5hrs (over three weeks) without figuring out what the issue was. Found this vid on cleaning the
CEM
(https://www.youtube.com/watch?v=QkG_tGTdoYk), which I tried with some hope last night, also no change.

The fact that it would not work for weeks, then suddenly run fine (often in connection to the weather conditions) makes me think this is a sensor issue that is floating around a fault value. Maybe a bad connection somewhere causing low value due to corrosion. Maybe a faulty engine control unit ("styreenhet"). The car today only has less than 125k km, and otherwise seems mechanically ok.

If you've made it this far, thanks for reading. As in the title, any tips greatly appreciated!