Just recently bought a 2012 S80, first thing I did was change the oil, 18 miles after the oil change the check engine light came on while the car was running. P0171: system too lean bank one.
I don't really live close to a dealer and would prefer not to have to take it to a mechanic. If anyone has any solution or things to check it would be greatly appreciated.
Thank you.
Also I have a scanner that does show me live engine data but I do not know how to interpret it or if a value is good or not.

 

You might accidentally cause vacuum leak somewhere. Especially check the 90 elbow (next to PCV valve) connected to air intake hose. To see if there is any leaking on either end