S80 Diesel Loss of Power

I definitely understand your frustration. I've experienced almost the exact same symptoms with my S80, although I'm riding a gasoline model. My mechanic pointed to a crankcase ventilation issue in my vehicle. The error codes matched yours? I advise you to also check your crankcase for any leaks; an improper crankcase ventilation can lead to oil leaks. I am no expert but my hunch is that you should have the components replaced. Let me know how it goes.

Thanks for the quick reply! When you say crankcase ventilation issue, was it definitely the valve itself that was faulty, or could it have been something else related to the ventilation system? And how did you confirm it was the valve specifically?

Good question! I can see why you're doing your research, but I do believe you are going down the wrong path. Truthfully, I lack the expertise to pinpoint the exact source. I was completely clueless about what crankcase ventilation even was, that's why I just took it to my local trusted mechanic. He replaced the valve directly, because it was the cheapest option and he didn't want me to spend useless money on troubleshooting first. If the issue still arose afterwards, we would have considered other factors. And that fixed it. I suggest you take your car to a trusted workshop and explain the issue over there.

Thanks so much for sharing your experience! That's really helpful. I took it to a local shop, and they confirmed it was the crankcase ventilation valve. Quoted 360€ for the replacement, which seems reasonable. Getting it sorted this week. Cheers!