PCV service turns into oil pan work.

[abscate]

You can beg borrow or steal a used oil filler cap , and drill a hole into it, to vent the crankcase to a tube running under the car. This will save your seals from popping out.

[altalake]

'04 XC70 170,000km - I completed the PCV service (FCP Euro suggests 3 1/2 hours - about 10% of what it took me) but with the oil sump return still plugged. Fired it up and it runs fine on initial start at 1,500rpm but with a dash warning "Reduced Engine Performance" and, once it drops down to idle, runs terribly. Haven't tried driving it yet.
VIDA shows 5 faults: BCM-0004, BCM-1000, BCM-0115, ECM-91B7 Throttle valve - Faulty signal, ECM-130A Air Leakage intake
I suspect it's the last two that are relevant. Checked hoses and pipes and connectors and everything looks good.
The car ran fine with no dash warnings despite a fully clogged PCV oil trap before I dug into it.
Any ideas of what I might have missed or messed up?
Thanks.

[vtl]

You introduced an air leak. Get it smoked. I have this one, it's sort of expensive, but, unlike my cheap DIY attempts, it actually worked.: www.amazon.com/AutoLine-Pro-Automotive- ... B07JVT1NG2

[altalake]

Thanks for the quick reply and good suggestion but it turned out to be something simpler. The electrical connector to the ETM - the one that's so hard to release - was not properly seated. All good now with no relevant error codes.

[altalake]

Follow up a year later.......
I did drive it with the plugged oil return passage for over 1,000km before getting the oil passage cleaned by a shop. No oil blow by and not even one drop of oil on the splash pan after a year.

[scot850]

Thanks for taking the time to update this thread.

Neil