2016 Forester Mileage drop after MAF sensor change

[lmdew]

2016 Forester,

Had a lean on #4.  I forget the code but it pointed to the O2 sensor or MAF.  Nephew changed the to a Denso  unit.  Mileage dropped from 24 to 16.  He swapped the original back, but mileage is still down.  I told him don't troubleshoot with the parts cannon.  MAF was the only thing he could get over the holidays in time.  Is there a good Free OBDII app we could download on his phone to see the fuel trim and O2 sensor readings.  Thanks, Larry

[Daskuppler]

On 12/28/2022 at 6:31 PM, lmdew said:

2016 Forester,

Had a lean on #4.  I forget the code but it pointed to the O2 sensor or MAF.  Nephew changed the to a Denso  unit.  Mileage dropped from 24 to 16.  He swapped the original back, but mileage is still down.  I told him don't troubleshoot with the parts cannon.  MAF was the only thing he could get over the holidays in time.  Is there a good Free OBDII app we could download on his phone to see the fuel trim and O2 sensor readings.  Thanks, Larry

Nothing free that I know of. I use the Innova 5610 scanner, it works best week on Subarus and is available on Amazon.

[heartless]

On 12/28/2022 at 7:31 PM, lmdew said:

2016 Forester,

 Is there a good Free OBDII app we could download on his phone to see the fuel trim and O2 sensor readings.  Thanks, Larry

there are lots of apps, but you still have to have a dongle to plug into the OBDII port to transfer the info to the app .. that dongle wont be free.

[brus brother]

any new codes?

disconnect battery and let the computer relearn?

Edited December 30, 2022 by brus brother

[lmdew]

No new codes.  They are on their way back to WA.  Gas mileage is a little better.

Subaru MAF back in.