2016 Forester - "Check Engine"

Oct 2, 2023
Reaction score
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!
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?
Last edited:
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?

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments. After that, you can post your question and our members will help you out.

Ask a Question

Members online

No members online now.

Forum statistics

Latest member

Latest Threads