Subaru Outback P0420 Again! Big Lesson Learned | Quick Diag and How to Replace the Converter 

EXCELLENT, I've been researching the P0420 for two days now. Your explanation and demonstration of the Temp, Pre and Post sensor readings really helped to bring all this together. Plus the added feed back from the muffler shop is good, but, not sure if I'm ready to spend $$$ on an OEM, darn.

Amazing and wonderful details ,Thanks for taking your time and sharing to the broader Subaru owners

Sometimes aftermarket products don't cut it... $1,700 for a freaking Catalytic Converter that's a crying shame...Well done

Great input! Thanks for the advice you gave us!

Very good video! Way to have confidence in your diagnosis to not only call a bad part on the replacement but also to convince the customer to spend $$$ on an OEM converter.

Your video gave me more knowledge on this subject, thanks.

Best video on this topic I've seen.

i really like the way this was presented 💕❤

I was able to clean mine using citric acid. It even took the rust off the pipe. 15k miles and 1.5 years later no p0420 code.

New subscriber,great video,thank you!!

Super informative thank you.

interesting information. thank you

Excellent tutorial:}

Thank you very helpful

Thank you for this informative video! But jeez, as if the oil burning and head gasket issues aren't bad enough, throw super expensive converters into the equation. On our 07 Forester, we'll just keep resetting the check engine light until we get a new (non Subaru) car.

great job, thanks

Very good description, demonstration and explanation. Now I'm just concerned about how expensive tomorrow's exhaust workshop bill could be... (identical car, in Straya) 😬

Part f the issue with some of the aftermarket converter/manifolds, is the FLOW, if you will, they restrict flow to and or from the converter, causing the sensors to read and throw codes.

Im about to just straight pipe mine if the replacement i ordered failed 😂 i didnt buy the OE spec converter but at this point any new converter is better than the box of rocks i got bolted on now

When it comes to spark plugs, does it matter too if you get it from your brand (my case) Hyundai OEM compared to auto zone spark plugs? I totally agree with aftermarket cause and effect ....thanks much

I just had my 2011 at the dealership for cats... quote came back at $9,110.50. I almost lit the car on fire. Went with Walker, so far the readings have been good. Fingers 🤞

Our 2008 outback, factory converter is 3800, Orange county California. Just the front converter. Thank God I've done all the work myself. video! Thanks for taking your time to post the video. God bless you in health and wealth. Subscribed to the channel. God bless you all working on these expensive subaru's. First and last subaru we'll own. I also want to burn this puppy down. Lol!

Yea you thanks for explain why parts cost more for quality. I noticed the larger chambers before and after the cat. Cool to see… it would be nice if we had a service for them. Like how to clean them that’s worth the effort. I herd lacquer thinner 1gal:1/2tank and 150 drive Miles. Any ideas?

Thanks for the video. My walker cat cracked on the pipe before going into the collector. Had that welded and im still getting the 420 code. Im assuming the bad walker cat and oil consumption on the engine is causing these issues. Im trying the spark plug fowler to just get rid of the code for the time being to pass inspection until I can rip the engine out and buy an OEM cat. Subaru's new moto " You'll love it till you hate it!" Does anyone know if a MagnaFlow OEM cat is as good as a Subaru? Or will it be another walker issue? The MagnaFlow is cheaper than subaru but twice the cost of a walker.

So the cat was the P0420 code, but what was causing the rough running?

this is actually good. you got a new sub!

ive had nothing but problems out of WALKER everything from bad ' IAC's to o2 sensors cats

New Sub here. Excellent video👍

You said the aftermarket lasted 2 years. You know how many miles it lasted for that customer? Also, what was the brand of the second aftermarket converter you tried that did not work out for you before settling on the genuine Subaru one? Thanks.

How often did the customer drive and what was the av drive time? Most cars suffer from under use and short trips. Not absolving Subaru from its issues but under use is just as bad as hard use

You are in the 760 in vista? You're not far from me. Thank you for the fed regulation info and I think I'm going to ask that my mechanic go oem on the converter I need for my Impreza. For lambda because you were using your device as an oscilloscope you were talking about the distance peak to peak, correct??

Hello Great video Have subaru crisstreck first gen. Have same readings on oxigen sensor BUT...i also hace water coming out of exaust...is that head gasket?...or converter? Thank you sonmuch

Thank you. Excellent presentation. I have a 2017 Subaru Crosstrek. OEM cat replaced by Subaru dealer at 42,000. Now at 67,000 the P0420 has shown up again today. Replacing both sensors first to see if that's it. If this 2nd OEM cat is bad, I'm replacing it with a Toyota. The key to all this started at 11:50 - "One thing to keep in mind....." this summed up the whole Subaru cat issue in a nutshell.

Think I’m on this road. Wish your shop was closer. I’d just let you deal with it.

Subaru OEM "pretzel" converters are up to $2200 just for the part, incredible.

was it due to the DENSOs?

Can someone get all those readings with a computer like yours? On a smartphone with something plugged in under the dash?

So if the exaust cant get through the converters then where did it go?

I have the same experience with my 2009 2.5i 135K Subaru Legacy. I bought it used with 135K miles. I use an OBDII device that connects to my phone. Replaced both O2 sensors, cat (Walker/Rockauto), spark plugs, spark plug wires, air filter, cleaned the throttle body, cleaned the MAF sensor, corrected exhaust leaks, added an oil catch can, changed the timing belt and pulleys. The car runs well and now, there are no codes, except for P0420. After the cat was replaced, passed CA smog, it ran for about 3500 miles before P0420 returned. Since then, the code will return every 180 to 500 miles after clearing the code. I have also tried Cataclean (twice), and removing the cat and cleaning with detergent like so many other youtube videos. The federal exchange warranty is useless. In my case, I would have to purchase another cat, send back the faulty one ($$ shipping), and IF Walker determines that the cat was bad, they will reimburse. Why would I want to purchase another cat ($700) that is likely to fail in less than 4k miles just to have Walker say it was poisened by my high mileage engine? (I don't expect them to say it was a faulty cat, eventhough it looks like an OEM cat will work much better). So, now I am at 174K miles 16 months later. From your video, I am nearly convinced that if I want the P0420 code to go away, I will have to purchase a new OEM cat and install it before getting it smogged in 4 months when registration comes due. I really enjoy the way this car drives. Its even enjoyable to work on. I just wish it was illegal for aftermarket parts manufacturers to sell products that do not meet OEM specs and to seduce buyers with meaningless warrantees. "Big lesson learned" indeed...great video!

so there no reason to buy a aftermaket cat? so cat delete it is

may cat was clogged also the up-pipe and they wanted 4k to change it

I changed out my front cat with an ap eastern. Ran amazing for 35 seconds. Now running like crap again. Can’t accelerate and shaking back and forth. Midas says it’s the rear cat too. What do you think?

Very good video, do you think the aftermarket one would las ta few thousand miles at least? Or would it have caused a check engine light right away because of the efficiency.

There is a second cat under the heat shield that fails and plugs the exhaust

Hey, just trying to diagnose a Cat issue right now on a 2009 outback. I ran some tests with my OBDII reader and the B1S1 reading sticks around 0.99 lambda under load (2000rpm) or at idle, but the reading i get for O2S B1S2 is around 0.865 to 0.9(V) under load and fluctuates a lot at idle. That second number seems high to me, but I don't have any fluctuations according to the graphs I'm seeing . The CEL only kicks on after I drive the thing for around 10-30 minutes at around 2500rpm, and shows P0420, and it doesn't do it every time it seems pretty random. Just trying to figure out what best course of action is and what is most likely cause in your opinion. Any input is appreciated. Was gonna run some cataclean through it tomorrow to see if that helped.

What diagnosis device are you using? How you get the results on your phone?

what was both cost

I’m having to replace mine any special tools needed ? How long it take you ?

What about the rear converter ? How to diagnose which one has failed ?

I have a 2013 crosstrek with 138k miles. Just got code p0420 can you replace the cst with a used one? I live in Cali so i cant just buy an aftermarket one.

That cat is now worth more than the car.

Didn't get it, why you replaced the cat converter. you said "check oil level, check for exhaust leaks, check O2 sensors". You found exhaust leak but still decided to replace it anyway. What was the reason, besides it was still under warranty?

Some subies require a California cat or a EPA cat.

My mechanic was quoted $7,000 For a new subaru Catalytic converter for my 2005 Forester. Of course this doesn’t include service and Labor. Any info is really welcomed Is this really inflated or is it real ??? The car has 74,000. Miles on it and I wanted to keep it?

Yeah just wrapped up a manivert on a sport trex what a pain in the ass solid pipe 600 dollars for a carb compliant piece of shit

Im so sick of the EPA polution bullshit really am!! Its all a money scam.