JDM Hatch running rich/P0420
 

Hi all,

Looking for some help with my JDM hatch. Car threw up a P0420 code when driving steadily on the motorway - cat efficiency low bank 1.

Fitted a new genuine front Lambda and cleared the code. Car was ok for a couple of days but then got the same P0420 code. Smells like it’s running rich and using a ton of fuel (more than usual for a Subaru!)

It’s booked for mapping next week (for uk fuel) but is there anything else I should be looking at in the meantime? Hoping it’s just the map needs looking at as it’s a completely standard car with the JDM map on it.

Any thoughts?

See attached.
Maybe the rear O2 sensor ??

cheers Don.

it’s had a new rear 02 sensor in the last couple of months unfortunately, fitted by the previous owner. I’ll give it a change anyway…never know if someone has fitted the wrong one!

well, checking the receipts this evening that came with the car and after a bit of Googling and searching ICP, turns out the rear lambda the previous owner put on the car is for a forester STi!

hoping and praying that this was the problem all along. Correct sensor ordered, fingers crossed

Looks like it could be the problem
Item 1 Forester STi
Item2 JDM Hatch

https://cimg7.ibsrv.net/gimg/www.sco...c800dfca26.png

I do hope so…appreciate all the info