2012 Subaru Forester OEM Catalytic Converter Manifold Replacement

After dealing with a couple different converter manifold setups, I just wanted to reliable solution to be rid of my P0420 check engine code once and for all; and the best solution to that was to replace it with a new OEM unit.
Also, while I was in there I decided to try to fit up the full undertray splash guard that comes on the turbo models in order to keep this new manifold protected a bit better from the northeast winter road salt spray.
OEM Non-PZEV Converter Part Number: 44620ac581
Forester XT Splash Guard OEM Part Number: 56410SC001
00:00 - Intro
00:46 - The Problem
03:23 - PZEV vs Non-PZEV
06:18 - Fed. Warantee?
07:14 - Removing The Mid-Pipe
10:15 - Removing The Splash Guards
10:40 - Disconnecting The O2 Sensors
11:41 - Removing The Manifold
12:23 - Swapping The O2 Sensors
14:09 - Note On Gaskets
15:02 - Installing The New Manifold
15:48 - Reinstalling The Mid-Pipe
16:54 - Re-Connecting The O2 Sensors
17:16 - Installing The "Turbo" Splash Guard
21:09 - Outro

[@jellipig]

Very helpful - thanks for the guide. I have the exact same car (PZEV, 146k miles) and I just did this with an aftermarket $460 converter from RockAuto. We'll see how long it lasts.
Cataclean did not fix the code
New Rear o2 sensor also did not fix the code
I guess my converter was fouled/damaged by excessive oil burn, so replacing cat was the only way (besides tuning out the code) to fix

[@PeterHernandez-lg2eh]

Good to know about the computer Pezv issue

[@ianyates8483]

On the engine splash guard (UK we call them under-trays) those 2 clips on the back tuck under a separate transmission splash guard on my 2010 sh

[@TwoFourSevenDIY]

Cool, thanks for the info!

[@jonathoncapaul2854]

Got a Forester that has a p0420 but the cam caps and valve covers are leaking too. I’m almost certain it consumes some oil too. Think I should just replace the cat and sensors and see how long it’ll last?

[@TwoFourSevenDIY]

It's hard to say. If it's consuming oil it's guaranteed to harm the cat again ... how long will it take to start seeing a p0420 again? Who knows.
Personally I would sort out your leaks and consumption issue first ... a new cat it's a decent amount a money to be taking chances with possibly damaging it

[@JohnKihl]

OK, we have the identical sh forester. On our vehicle we wheir Not able to have the Oil consumption issue fixed?
! So we are forced to use chemicals to keep carbon build up under control.
What suggestions like Cataclean would you give to keep the new cat converter as clean as you can?

[@TwoFourSevenDIY]

I've never attempted to use cat cleaner

[@JohnKihl]

Thank you for the reply, what did you end up doing to remedy the oil burning issue?

[@TwoFourSevenDIY]

The dealer performed the consumption fix waaay back at 50k miles.

[@JohnKihl]

What did they end up doing?

[@TwoFourSevenDIY]

Basically it was a tolerance issue in the original FB25 case halves, so they pull the engine, split the case halves, reuse your rotating assembly and put it into two new revised case halves and reinstall everything.

[@PeterHernandez-lg2eh]

Troubleshooting a po302 on my 2006 Subaru sti. My be a catalytic converter issue

[@TwoFourSevenDIY]

P0302 is a missfire code ... unlikely that it is a converter issue.