2018 Subaru Forester — catalyst efficiency code but car drives normally

If it were in my driveway, two 2018 Subaru Foresters can feel identical and have different causes, so measure before you copy someone else's repair. Don't erase codes until someone who can help has seen them. This is from a 2018 Subaru Forester in Detroit with 105,500 miles. Stop there until you know. I'll update if anything new shows up.

Intermittent stuff lies if you only catch it once. Move a coil or plug on the 2018 Subaru Forester if it's cylinder-specific and see whether the code follows. Don't erase codes until someone who can help has seen them. On “catalyst efficiency code but car drives normally,” that was the fork that mattered for me. If you share a photo of the worksheet, easier to sanity-check. This is me being the wet blanket on purpose.