Read https://www.swedespeed.com/threads/2016-xc90-t5-intermittent-seasonal-p0171.660776/?post_id=8017552&nested_view=1&sortby=oldest#post-8017552 which suggested resetting the ECU. Disconnected the main 12V battery in the trunk (along with the plastic module on top of the positive terminals ...

Replaced the PCV today (sheared a bolt torquing it down - added a couple hours to the project while I ran out for an extractor), as well as the upstream O2 sensor. The washer gasket on what I think is the pressure valve on the PCV was cracked (looked like it might have been "stuck on" and ...

Hey all - I've got a 2016 XC90 just shy of 80k miles. Threw a P0171 code (fuel trim too lean on bank 1) a couple months back. After doing some homework on this site and others, I've tried/crossed off: No squealing from the oil cap/PCV. Looks like the PCV might be leaking a very tiny amount of oil, b...