I purchased a used 2009 S80 T6 with 57k miles. It was a corporate car in its previous life and It ran great and smooth. Eventually, code P0171 appeared and I began
troubleshooting: Cleaning the throttle body (it was gunked up), cleaned the mass airflow sensor with a mass airflow cleaner.

Can a busted diaphragm on an oil trap cause no start? My 2009 S80 apparently had a malfunctioning oil trap and caused the engine power to drop while I was driving. After returning home I was going to drive the auto store to have them read the codes, however, my car sputtered and stopped. This happened after a few attempts and it has not left the driveway since.

I just bought a new oil trap and I am running through my troubleshooting options before installing this part.

 

I've never seen a vacuum leak in an oil trap cause a car to stall and not restart. I'd start with basics - don't know how competent your scan tool is but good ones or VIDA can view all sorts of live information. Spark, injector pulse, fuel pressure. And measure the fuel pressure with a gauge also.

 

It is possible that some of the oil made its way into the intake. Did you see any smoke / oil consumption prior to the stall out? You may want to inspect the intake (MAF, throttle body) to make sure its clean. If need be you can try cleaning the MAF (don't use carb cleaner, use a product like CRC MAF Cleaner - about $8 a can at Autozone or Walmart.)