2016 Forester - "Check Engine"

[clanofwolves]

Hey guys,

My wife's 2016 Forester 2.5i 6-speed just had, on a very cold morning here, the following come up on her dash screen, "Check Engine, Emission Control System needs to be checked." She is at her mother's home 3 hours away, so I cannot attach my Foxwell scanner on it and pull codes. But I just wanted to ask what you guys have seen with this, as the car has had no issues, and she says other than the dash indicator, the car is running great.

Thanks in advance!

 

[clanofwolves]

So the car's in the driveway, drove back fine my wife said. I pulled the code and it's: "PO171 System Too Lean Bank 1." MAP sensor cleaning or? Maybe I need to run and get the live readings of the fuel trim?

 

[clanofwolves]

Interesting detail: since the "check engine" code came on during a very cold startup (25 deg), I erased the code and during my wife's warmer startup and current AM's drive, the code has not returned. That said, it seems the issue is cold initiated, so something is reducing in size and causing an issue. I'm not sure if this makes troubleshooting easier?