On my 2004 Subaru Legacy 2.5 I spent a lot of money on diagnosis and O2 sensors as well as spending time trying TH-cam quick fixes. In the end, got both cats from Rock Auto (Eastern Catalytic) and they've worked fine for over 10K miles. The Rock Auto price was around $600 and I got $60 from the junk yard for the old cats. Subaru wants about $2000 for the cats. OEM are undoubtedly better, but I'm not sure they are three times as good. My originals went about 120K miles before the P0420 showed up. I was able to jury rig the old heat shields into place. Seems as if they would be important. Also used exhaust insulation tape to replace the old insulation between the heat shield and the exhaust pipes. My car is manual transmission and the Eastern Catalytic converter had brackets that I assume were for an automatic. Some strap steel and pipe clamps enabled another jury rig and have had no further issues. This took me 8 hours and for the money I saved I made over $180 per hour for my time. I also learned that you can spend a lot of money on diagnosis and O2 sensors trying to save money on catalytic converters.
This is by far the most interesting deep well insight explanation of details of honey comb inside a cat converter that I found on yt…appreciate u brother for sharing this with us…you’re definitely worth more than a precious metal!
My Xterra has 4 catalytic converters, for the price to change them I found rebar as a great alternative, combined with a piece of electrical tape to cover the check engine light with
Awesome! I love the way the information is conveyed. Understandable, with technical points and some light humor. End result information to spec and the reason why.
One thing about that chemical equation is the consumption of O2. This can be used as a diagnostic advantage. On the scantool pull up the S1 and S2 O2’s on the suspect bank. If the cat is working, then obviously it consumes the incoming O2, therefore S2 must show fixed rich. If the cat is not efficient, then the incoming O2 is not consumed- it will be identical to the S1 trace since nothing is changing! Confirmed diagnosis of activity or failure of catalyst.
Brian thanks so much for this video, it helped me a lot, I have an 04 Outback with the EJ259 and CA emissions that was running like crap, I ended up needing all new AF and 02 sensors as well as a new exhaust with new cats. The Car has 259k miles on it I believe the motor was rebuilt at about 180k and at some point around 225k the sensors failed which probably is what caused the cats to burn up. Nothing lasts forever, but after all that was fixed it runs really good again. Really appreciate your videos so I hope that fills your tank a bit!
Man i love how much detail you go into and that you explain the science behind this stuff. Great video, thanks for your quality of work and quality of channel!
I watch vids for hours every night and for some reason I feel this is one of the best vids I have ever watched. Awesome job and nobody could ask you to be any more thorough than that! I guess this is an old vid so I doubt you will see my questions but I will try anyway. How many miles did that Subaru have on it and is their a somewhat typical mileage where the cats get clogged? I have a 2006 Subaru Baja with a 2.0 JDM dropped in by the previous owner. The car bogs in second gear and doesnt like to climb hills......the JDM I am hoping was installed and converted correctly........but the shop I just took it to I assuming that the cats are clogged. I have 183K on the exhaust system........One clue is the engine sucked in a baseball indent on the air filter....nobody has ever seen that before but seems like it is pulling air hard. So I ordered a cheap ebay cat section to just have the shop run it with free air flowing to see if that solves the bogging problem. What aftermarket cats do you recommend for Subaru 2.5 's? Thank you
I don't know if the flashing cruise control light went away after you put some drive cycles on the car after replacing the cat; but I learned that after you clear the P0420 code, just turn the car off and turn it back on, but don't start it. Then use the cruise control control on the steering wheel column to turn the flashing cruise control light off. Just hold the control in the off position until the light goes off and you are good to go.
Thanks man. I needed a nap. The video was super extra good. Grinding and cutting just puts me to sleep when that's what I need. :) Cheers. In my limited experience on replacing cats usually aren't melted when they're bad so it was lucky you got share that on top of a good fix. P0420 and P0430 are my favorites. They're my first codes I learned to fix and I claim I'm expert on them and all the ways a car can be wrong, that they're actually good. Not that this is a complete list, but exhaust leaks can set false P0420's as random volumes of air can enter the exhaust via venturi's. These centuries aren't consistent so it can simulate the stoichiometric wave pattern of an upstream O2 sensor. Stuck O2 sensors upstream can cause larger fuel trim adjustments, which can set P0420's or 30's in seconds, though usually more time is required.
Of course AutoBravado, when you've replaced catalytic converters you've only had one which could be seen through without a cut down. Be sure to recycle the old catalytic converter for money. I know of a man who used to fix exhausts until he found out he could make more money cutting out the precious metals to sell as valuable scrap. Haha
I had the p0420 for years on my 02 Outback. Eventually I ended up with mysterious fuel delivery issues, chugging loss of power. Replaced the upsteam O2 sensor and it fixed both. Bad upstream sensor can confuse the catalyst reading.
thank you for explaining this. my daughter had the same car and I cleared this code twice in the last 2 months. Looks like a simple fix that I can do at home. Only question is...did I see you install the new cat with no heat shield on it? or did I miss something?
Nice of you to take the time to deconstruct the CAT. Thanks for adding the explanation of the cause for the excess unburned hydrocarbon in the exhaust. Few people understand that excess hydrocarbon cause over heating and CAT failure. Did the owner first repair the compression problem or did they want you to throw on a new CAT so they could sell the vehicle as is? By the way, there is a couple hundred dollars of precious metals in the converter. I hope you have a place that takes them in trade.
OK. You did not show how you corrected the problem that caused the cat to go bad. They say the cat should last the lifetime of the car, if the car is in good running condition. Is that really true? I burned up one cat by towing a very heavy trailer with a 2002 Lesabre from Orlando to Virginia and overheated the engine. So, I replaced it with a universal EPA cat that lasted for 36,000 miles. So, does that prove there is a problem with the engine that needs to be corrected. The folks at Bosal said that the replacement CAT would last for a hundred thousand miles or more for a properly running engine. thathigh
So many times I have heard these kids at the Zone or the other one go, "urrr it needs an oxygen sensor." I've never seen it be anything but a converter. Sometimes if I feel adventurous I'll try to help them and explain that the O2 sensor is doing its job there. Also, with Subaru, I have found that the Walker branded converters either don't work at all, or only work for a couple thousand miles before throwing the code again.
+Eric Brunhammer Truly amazing how they can intuit a code cross like that. O2 sensors have their own codes and P0420 ain't it - yet changing an O2 sensor is the first thing that pops into the head for them. Here's a thought, you can't have a p0420 if the O2 sensor system (read BOTH of them) is defective first.
As an automated feature built into the ECM as In my 2010 Forrester The cruise control light will blink when a 420 code check engine light comes on as the dealer instructed me, " It's a safety feature!" Coincidentally my TCS light, also came on with the CEL and blinking cruise light as, you guess it, "a saftey feature!". thus 3 lights in all will go on for one simple 420 code. This TCS may play havoc with the ABS, they seem to be the sides of a coin, one forward, one backward. game of crazy dominoes. But once the 420 code is cleared seems the others fall in line.
Thank you! Dealership wanted $2,200 for a new cat for my daughter's 2010 Impreza. It had an actual exhaust leak, no codes. I went after market and did it myself. Interesting to see what these overpriced things actually do.
I replaced my exhaust manifold/cat in April and I now have a p0420. It was a cheaper one on ebay for an 07 forrester. I hope its not s bad one. checking with the seller on the warranty.
Hey Brian, just a clarification on gasoline constituents... MTBE is no longer used in North American fuels due to water pollution and heath risks. Phase-out of MTBE began in California in the early to mid 2000's and became banned in several states including California and New York State in 2004, and by additional states by 2005 and currently is not in use as a motor fuel additive anywhere in the US or North America Reportedly MTBE is currently only used in seven countries outside of the US, all of the other countries have banned the use of MTBE as a motor fuel additive. Those seven countries are in the process of phasing out MTBE completely. Nice reveal, that cat has experienced some serious heat to melt the ceramic carrier.
+patw52pb1 Thanks Pat! GREAT COMMENT! I love learning from guys like yourself who know this specialized stuff. There's so much to know, and then it's outdated before you know it. What industry do you work in?
It's not used anymore cause it was stored improperly which resulted in a large quantity of it going out to the environment (which is obviosuly bad) and that's why we have ethanol in gas instead :/
nice and very informative video. if you have time, you should make a video on how to weld a universal aftermarket cat in to it. dont know the success rate on those though.
+Sean Black Thanks Sean, do you feel like you could do it with a scanner now having seen what the numbers are for a bad and then a good cat for the rear O2 sensor? Bad cats fluctuate from .01V up to 1V when the engine is warmed up, and good cats hang out at .7V with dips every so often at idle after they're warmed up.
Good video!! This convinced me to replace my cat. Altho, I used 2 bottles of CatClean for awhile and that worked. But now, the codes are back. Time to replace it.
I love your approach. Skillful, Sarcastic, curious and in some ways philosophical. It's much appreciated! Thanks for quenching my curiosity as well. Ps: know where I can get a cat for a sulev accord? I'll pay ANY amount for a new one, but I can't seem to source it 😢.
Adam Alsnayyan - sounds right. On my Toyotas I always get the Traction Control Light and the Vehicle Stability Control (VSC) lights to come on when the Check Engine light is on. Three separate yellow lights. Great video Brian. Thanks. P.S. - be more careful with that grinder! Hate to see you get hurt.
Thanks, think this made me fully understand that I most likely have a clogged CAT. Audi B8 which had piston issue causing oil leak, that was fixed but it seems the oil leak may have caused the honeycomb to burn out & get ashy in the CAT.
Brian, in the opening with the machete, well it's used in automotive service the same way my wood splitting maul does, as an extra too... My maul has seen more metal than wood I believe, the back make for a great BFH!
Great info. Just replaced both of my cats on the same car. Now its on its face with a p0420 code only. Probably half my power is gone. Im lost. Scanner tests MAF and both 02 sensors ok as well as fuel trim. Another mechanic told me I now need to replace them both with CA cat's as it used to be a CA car >< this doesn't make sense to me
I'm sorry, I may have missed it in the explanation, did you explain why this particular cat failed ? I ask because I have an Aussie 2005 Mitsubishi 380 ( Galant in the U.S.) with 356000 klms. It has an east-west 3.8 V6 and shows both banks below threshold. I know she's cooking oil probably via the valve stem seals and that's most likely why my cats are screwed. But aside from a constant engine light the car's running great. Honestly, I can't justify the cost of two new cats unless I rebuild the engine and I keep getting told NOT to just redo the heads. Anyway, the point being is that I couldn't just chuck on a couple of new cats without addressing the issue that caused the failure in the first place. Not only for the cost of the cats but the huge job of removing the cat from the rear bank. Great video and thanks for going so far into the can that holds the honeycomb. I reckon mine must look as least as bad as that.
I may be stupid buttttttt, it the REAR CAT is receiving tooooo much hydrocarbons causing overheating - then doesn't that have be jacked up from the FRONT CAT sending shit downstream to the REAR CAT? Does this vehicle only have one, two, three or four CATs - you have upstream and down stream bank 1 and upstream and down stream bank 2? How do you know the engine management and electronic ignition (TPS, MAP, MAF) is giving correct input to burn efficiently? I guess the answer is the upstream sensor would pick that up. I am not saying you are wrong but aren't there a few tests to confirm there is nothing else wrong - evap purge valve and will the evap purge valve stuck open cause 02 sensor to go bad - did you check the O2 sensors up stream? I was an aircraft electrician for 22 years so I have experience since almost every system on a car came from aircraft - doesn't make me an expert just asking questions cause I got a 0420 code - but the idiots at grease monkey didn't put enough oil in because they had the rear of the car lifted on the ramp so it indicated full when we got the oil light it was 2 1/4 quarts low - seems that oil change and car manufacturer with engine light at 2 1/4 quarts low coming on is a problem but I am wondering what it did to the system - O2, CAT because the 0420 code set not long after the oil low light and there was baked on oil on the dipstick and smelled burnt - I put Lucas engine oil treatment to help some and I am wondering - will a sea foam engine treatment a couple times - and a fuel cleaner several times do anything to clean the CAT or O2 sensors? Is there a way to clean cat on vehicle?
Thanks for the Video. I am getting the P0420 also, my O2 bank one sensor is steady while the bank 2 sensor is all over the place, have a hard time believing a 2013 vehicle needs a new cat!
that is revealing how you're in a bad way when they get crumbly. I have now a 3" tubular converter made by thrush. It takes all the hypo carbons and converts it to sound. The pimple faced kid at the auto parts desk explained it to me
+Albion Laster Wow. I wish I could take him under wing for a few weeks. I worked at Autozone when they were a privately held company and witnessed the destruction of that business model by share holders relating to such phenomenon. I used to have time scheduled to train new hires- then they cut everything except "plan-o-gram" time wherein we transformed the place to resemble a cleaner version of a Tijuana street shop. We packed the isles full of plastic car junk from China while one poor soul frantically ran counter and told people whatever the hell it took to get them to buy and move on. All this because the owners daughter got cancer and didn't have the time/need/money to care for family and the business. Nuts. I'm always curious why things break down. My head can't let go of something till I have answers. Everyone is that way to some degree. Sometimes we accept filler material as a substitute so we can cope. It makes us comfortable till that information fails us when we try to use it.... like so much Chinese plastic car junk from Autozone.
Why didn’t you put the heat shield on the new pipe, it came off easily.? That’s half the job and with the book rate you are charging it would more than cover the time required....just saying. Interesting video!
The voltage you were looking at in the video what sensor bank/location was this? Trying to troubleshoot an issue on a 09 legacy. I replaced the o2 after the cat and still having troubles. The car seems very sluggish and does not want to accelerate at highway speeds. Had a p0420 awhile back but it hasn't threw the code again in awhile. Was considering changing the pre cat sensor (the air fuel one) before trying a new cat/exhaust manifold.
What brand is that new cat (it looks really nice), I'm having the same issue with my 2007 Impreza with 200K miles on it. Awesome video, thanks so much for recording/sharing!
eddiejclayton1 2006 Impreza orbs with 200k. What did you figure out? I have lots of stuff in my amazon que: gaskets, o2 sensors, cataclean, new headers/cat, 02 debunker. Torque wrench, pb welder lol jk already had that. Thinking about going down to one cat. What was wrong with yours? Did you dissect it?
My ‘01 Forester has this same P0420 code and so do a lot of other ppl in the forum.. Is it actually safe running without the 2nd Cat? I might just do a 2nd Cat delete.. Will the code still show if there’s no Cat? I’m actually amazed at the construction of a Catalytic converter.. Thanks for the video Brian!
I didn't catch the Scotty Kilmer reference, except when you showed a photo on the side like he did. I did notice the DeWalt and Hitachi tools and appreciate the 'just say no to Harbor Freight tools.'.....they creep me out. Buy there, and be ready to buy it again. I have good tools from over 2 years ago, that won't happen with Chicago Electric. Stop buying Chinese shit. Subscribed! That was a thorough review for my Toyota. I was clinging to not believing it was the cat but didn't want to throw a bunch of parts ten find out it was the cat. I think my Corolla has this same manifold cat in addition to below, nice to get confirmation. I'm going to try running w/o the upstream sensor, I wasn't sure if you could do that.
I’ve been researching aftermarket cats for my 2008 Legacy, and unfortunately the general consensus seems to be OEM is the best bet if you don’t want to replace it in 4-6 months, I’ve seen 2 or 3 now that all said no more aftermarket cars only OEM, something about the aftermarket ones restricting air flow and just not lasting. Any recommendations for reliable options that aren’t 1700 bucks, I may just try to find one either way a blown motor and buy it just for parts and the cats, I need total exhaust it’s all rotted out.
Hey great video just got a p0420 on my 08 suabru impreza. I determined that yes my cat is bad but my question is can you tell me what caused it to go bad. Cause I dont want to change the cat for it to go bad in a year or two. Is this a common problem for my impreza?
Hey man, love your videos, thank you! Working on a 02 llbean with 200000, not sure if cats ever been replaced, but it’s throwing a very intermittent po420, cleared on its own. I don’t have a live reader to check 02 sensors, and I don’t just want to throw parts at it. Subaru said it’s pretty straight forward on the phone and said it’s the cat.. where should I start? Would o2 sensor be intermittent or would cel stay on? Any advice would be huge. Thanks boss!
Did'nt realize the cat was that small. Was well clogged up and well diagnosed.Big difference in the reading of the rear sensor when new cat was installed.Computer was on target with the code. Can't whack the post mortem to confirm the reason for the code.
Had a P0420. Replaced both O2 sensors. Nothing. Dreading replacing cats. Engine was running like crap and still putting off cats so took it in to a subie specific shop. They cleaned out my throttle body and reset the cpu. 0420 gone going on a month now. So check that throttle body : )
Thanks for doing this! I know I asked if maybe you could go over this a while back and I think it helped me... now I know I need to drop all my money on a new cat. For an 02 forester, what brands or companies do you trust enough to recommend a new cat?
Great vidjea! This happened to my 04 sun fire. Car wouldn't rev past 3500, cat was all broken apart and blocking the exhaust like you mentioned. A sawzall fix it!
What can happen if I use a gallon of lacquer thinner to a quarter of a tank of gas. So say it can clean the catalytic system if it's not to far gone. Should I try it.?
Hi Brian, great video and great topic, keep up the good work. Also just want to ask why is it that this video is in 480p? most of your other videos are in 1080p. thanks
I got a 2011 Chevrolet Traverse i just bought with 222k miles. Test drove it 3 times before i bought it and ran fine every time. Had a 40 min drive home from lot and about 30 min in the rpms started to drop. I took it to auto zone and got it tested for free and they said it was a bad catalyst system low efficiency bank 1. Told me to try Cadi clean but they was out every where so i got a diff brand and it took the check engine light off but it still ran like shit. Put it in a shop and they charged me almost a k to replace the first one. I get it back and drive my wife to work that night and it does the same stuff. Took it back to auto zone and it pops for the same thing. Do you think it a bad o2 sensor or converter that is post to be new. Cant get no one to answer my call at the shop in 4 days. Also if it is o2 sensor are they required to fix it for free since they misdiagnosed my car. They even told me it was the converter.
Hello, I live in Drfting, PA, I was wondering do you do local repair work? I have a 2006 outback, died on my way home from work, I think it is a broken timing belt but I assume that means more damage was done internally when this happened, well that is what my husband thinks, I was wondering if you do those kinds of repairs? Thanks Carrie
Excellent video, as always! Also relevant to me as well, as my jeep is throwing a code about my cat. So with you down south now, you hitting up Brian's Head? I'd love to board some mountains surrounded by red rock. Also, you ought to make something nifty out of that old cat! The way that thing melted is almost artistic.
I have a bluetooth FIXD device, not a full computer output I guess? It tells me that the Oxygen sensor has has failed, the Evap system has failed and the Catalyst system has failed (and emailed me the P0420 code). my battery went dead it also tells me I have insuffient miles, might the problem go away with just driving around some more?
Dang, the old cats are worth some $$$ in scrap. Had a P0420, the cat had a small ding from the car bottoming out. Pulled the cat and there was absolutely no material left inside. Blew it all out the exhaust once damaged.
At the repair shop my 2010 Ford Sport Trac, 2WD showed a check engine light PO430 cat converter inefficiency error code. The car had a few symptoms: reduced gas mileage (16mpg to 12mpg), loss of acceleration to take off from a stoplight and continue up a hill with good power. Should I start by replacing the O2 sensor? I had the antifreeze flushed and filled and the shop did not find any leaks, but the reservoir was low. It has been bitterly cold.-- I am not sure that I want to replace the cat converter until I know what caused it to fail.
Hey, Brian, using the non-contact temp probe, what is an acceptable temperature differential between the inlet and outlet of the catlytic converter? I've heard about 100 degrees, but wondered if this still holds true. I know it varies, but was looking for a general range. Thanks!
It's so great to actually watch and listen a technical mechanic who knows exactly what he's talking about. Excellent video.
Thank you.
I can't believe I watched this whole episode on the catalytic converter, just because he was actually interesting. Good job man!
I’m an ASE Master Technician
I always learn something from your videos.
thank you, Brian!
This video has it all. Probably the only one I've found that actually diagnoses this code correctly. Also you have a nice view from your garage!
22min later, I'm still glad I watched! Thanks for the overly informative and fascinating video!
On my 2004 Subaru Legacy 2.5 I spent a lot of money on diagnosis and O2 sensors as well as spending time trying TH-cam quick fixes. In the end, got both cats from Rock Auto (Eastern Catalytic) and they've worked fine for over 10K miles. The Rock Auto price was around $600 and I got $60 from the junk yard for the old cats. Subaru wants about $2000 for the cats. OEM are undoubtedly better, but I'm not sure they are three times as good. My originals went about 120K miles before the P0420 showed up. I was able to jury rig the old heat shields into place. Seems as if they would be important. Also used exhaust insulation tape to replace the old insulation between the heat shield and the exhaust pipes. My car is manual transmission and the Eastern Catalytic converter had brackets that I assume were for an automatic. Some strap steel and pipe clamps enabled another jury rig and have had no further issues. This took me 8 hours and for the money I saved I made over $180 per hour for my time. I also learned that you can spend a lot of money on diagnosis and O2 sensors trying to save money on catalytic converters.
This is by far the most interesting deep well insight explanation of details of honey comb inside a cat converter that I found on yt…appreciate u brother for sharing this with us…you’re definitely worth more than a precious metal!
My Xterra has 4 catalytic converters, for the price to change them I found rebar as a great alternative, combined with a piece of electrical tape to cover the check engine light with
Awesome! I love the way the information is conveyed. Understandable, with technical points and some light humor. End result information to spec and the reason why.
One thing about that chemical equation is the consumption of O2. This can be used as a diagnostic advantage. On the scantool pull up the S1 and S2 O2’s on the suspect bank. If the cat is working, then obviously it consumes the incoming O2, therefore S2 must show fixed rich. If the cat is not efficient, then the incoming O2 is not consumed- it will be identical to the S1 trace since nothing is changing! Confirmed diagnosis of activity or failure of catalyst.
+Schrodingers Box - Matt, You were probably wetting your pants when you saw them dear equations ! LOL!
Billy R Hahahaha almost- Organic Chem not my thing but still appreciate a balanced equation!
Schrodingers Box LOL !
Brian thanks so much for this video, it helped me a lot, I have an 04 Outback with the EJ259 and CA emissions that was running like crap, I ended up needing all new AF and 02 sensors as well as a new exhaust with new cats. The Car has 259k miles on it I believe the motor was rebuilt at about 180k and at some point around 225k the sensors failed which probably is what caused the cats to burn up. Nothing lasts forever, but after all that was fixed it runs really good again. Really appreciate your videos so I hope that fills your tank a bit!
Man i love how much detail you go into and that you explain the science behind this stuff. Great video, thanks for your quality of work and quality of channel!
I watch vids for hours every night and for some reason I feel this is one of the best vids I have ever watched. Awesome job and nobody could ask you to be any more thorough than that! I guess this is an old vid so I doubt you will see my questions but I will try anyway. How many miles did that Subaru have on it and is their a somewhat typical mileage where the cats get clogged? I have a 2006 Subaru Baja with a 2.0 JDM dropped in by the previous owner. The car bogs in second gear and doesnt like to climb hills......the JDM I am hoping was installed and converted correctly........but the shop I just took it to I assuming that the cats are clogged. I have 183K on the exhaust system........One clue is the engine sucked in a baseball indent on the air filter....nobody has ever seen that before but seems like it is pulling air hard. So I ordered a cheap ebay cat section to just have the shop run it with free air flowing to see if that solves the bogging problem. What aftermarket cats do you recommend for Subaru 2.5 's? Thank you
I don't know if the flashing cruise control light went away after you put some drive cycles on the car after replacing the cat; but I learned that after you clear the P0420 code, just turn the car off and turn it back on, but don't start it. Then use the cruise control control on the steering wheel column to turn the flashing cruise control light off. Just hold the control in the off position until the light goes off and you are good to go.
For real? This is the first I've read this anywhere. I can't wait to get home and try.
Thanks man. I needed a nap. The video was super extra good. Grinding and cutting just puts me to sleep when that's what I need. :) Cheers.
In my limited experience on replacing cats usually aren't melted when they're bad so it was lucky you got share that on top of a good fix.
P0420 and P0430 are my favorites. They're my first codes I learned to fix and I claim I'm expert on them and all the ways a car can be wrong, that they're actually good.
Not that this is a complete list, but exhaust leaks can set false P0420's as random volumes of air can enter the exhaust via venturi's.
These centuries aren't consistent so it can simulate the stoichiometric wave pattern of an upstream O2 sensor.
Stuck O2 sensors upstream can cause larger fuel trim adjustments, which can set P0420's or 30's in seconds, though usually more time is required.
Of course AutoBravado, when you've replaced catalytic converters you've only had one which could be seen through without a cut down.
Be sure to recycle the old catalytic converter for money. I know of a man who used to fix exhausts until he found out he could make more money cutting out the precious metals to sell as valuable scrap. Haha
Breakdown of function is fantastic !
I had the p0420 for years on my 02 Outback. Eventually I ended up with mysterious fuel delivery issues, chugging loss of power.
Replaced the upsteam O2 sensor and it fixed both. Bad upstream sensor can confuse the catalyst reading.
thank you for explaining this.
my daughter had the same car and I cleared this code twice in the last 2 months.
Looks like a simple fix that I can do at home.
Only question is...did I see you install the new cat with no heat shield on it?
or did I miss something?
awesome internal operation!!! now I have the brightest idea what's inside the catalytic converter, keep it up bro!!!
Thank you! You should write the repair manuals! Finally someone that actually explains things like we don't know what we are doing! Thank you! 😊
good tips brian..another way to check is tap on the outside of the converter with a rubber mallet..if you hear that rattling its broken.
Nice of you to take the time to deconstruct the CAT. Thanks for adding the explanation of the cause for the excess unburned hydrocarbon in the exhaust. Few people understand that excess hydrocarbon cause over heating and CAT failure.
Did the owner first repair the compression problem or did they want you to throw on a new CAT so they could sell the vehicle as is? By the way, there is a couple hundred dollars of precious metals in the converter. I hope you have a place that takes them in trade.
OK. You did not show how you corrected the problem that caused the cat to go bad. They say the cat should last the lifetime of the car, if the car is in good running condition. Is that really true?
I burned up one cat by towing a very heavy trailer with a 2002 Lesabre from Orlando to Virginia and overheated the engine. So, I replaced it with a universal EPA cat that lasted for 36,000 miles. So, does that prove there is a problem with the engine that needs to be corrected. The folks at Bosal said that the replacement CAT would last for a hundred thousand miles or more for a properly running engine. thathigh
Brian, big thanks for sharing your experiences
New spark plugs and 2 cans of BG 44K squashed my P0420 Code. 2014 Nissan Sentra SR 160k miles. Good luck!
Cool like the fact that you show it step by step. Im a woman and i like learning about parts on cars.
So many times I have heard these kids at the Zone or the other one go, "urrr it needs an oxygen sensor." I've never seen it be anything but a converter. Sometimes if I feel adventurous I'll try to help them and explain that the O2 sensor is doing its job there. Also, with Subaru, I have found that the Walker branded converters either don't work at all, or only work for a couple thousand miles before throwing the code again.
+Eric Brunhammer Truly amazing how they can intuit a code cross like that. O2 sensors have their own codes and P0420 ain't it - yet changing an O2 sensor is the first thing that pops into the head for them. Here's a thought, you can't have a p0420 if the O2 sensor system (read BOTH of them) is defective first.
This was great, so glad I tuned in!! Now let's go skiing!!!
As an automated feature built into the ECM as In my 2010 Forrester The cruise control light will blink when a 420 code check engine light comes on as the dealer instructed me, " It's a safety feature!" Coincidentally my TCS light, also came on with the CEL and blinking cruise light as, you guess it, "a saftey feature!". thus 3 lights in all will go on for one simple 420 code. This TCS may play havoc with the ABS, they seem to be the sides of a coin, one forward, one backward. game of crazy dominoes. But once the 420 code is cleared seems the others fall in line.
I dissect a lot of things myself, but I never thought of that one ! Great Vid !
Excellent Video Brian. I'm actually directing one of my customers to this video that needs a Cat replaced on his Sebring. Thanks.
I'm 60 plus years old and enjoy your videos.
Thank you! Dealership wanted $2,200 for a new cat for my daughter's 2010 Impreza. It had an actual exhaust leak, no codes. I went after market and did it myself. Interesting to see what these overpriced things actually do.
I replaced my exhaust manifold/cat in April and I now have a p0420. It was a cheaper one on ebay for an 07 forrester. I hope its not s bad one. checking with the seller on the warranty.
Hey Brian, just a clarification on gasoline constituents...
MTBE is no longer used in North American fuels due to water pollution and heath risks.
Phase-out of MTBE began in California in the early to mid 2000's and became banned in several states including California and New York State in 2004, and by additional states by 2005 and currently is not in use as a motor fuel additive anywhere in the US or North America
Reportedly MTBE is currently only used in seven countries outside of the US, all of the other countries have banned the use of MTBE as a motor fuel additive.
Those seven countries are in the process of phasing out MTBE completely.
Nice reveal, that cat has experienced some serious heat to melt the ceramic carrier.
+patw52pb1 Thanks Pat! GREAT COMMENT! I love learning from guys like yourself who know this specialized stuff. There's so much to know, and then it's outdated before you know it. What industry do you work in?
+briansmobile1
I am currently involved in multiple industries, automotive, motorsports, energy, communications, electronics and manufacturing.
It's not used anymore cause it was stored improperly which resulted in a large quantity of it going out to the environment (which is obviosuly bad) and that's why we have ethanol in gas instead :/
no worries about the dust/fumes... prob good for the immune system-awesome
nice and very informative video.
if you have time, you should make a video on how to weld a universal aftermarket cat in to it. dont know the success rate on those though.
Title made me laugh because of how much a nightmare tracking down a P0420 in a Subaru is. Good info.
+Sean Black Thanks Sean, do you feel like you could do it with a scanner now having seen what the numbers are for a bad and then a good cat for the rear O2 sensor? Bad cats fluctuate from .01V up to 1V when the engine is warmed up, and good cats hang out at .7V with dips every so often at idle after they're warmed up.
This guy really knows his stuff, thanks.
Excellent presentation I finally realize what exactly is going on inside converter and got an idea on diagnosing.thank you!
Hello Brian, Another great video, Educational, informative and entertaining. Many Thanks
+joel mccoin Welcome Joel! Great to see you!
keep the guard on . I've had a disk explode on me when cutting in a shitty spot . my fault really but damn .
Good video!! This convinced me to replace my cat. Altho, I used 2 bottles of CatClean for awhile and that worked. But now, the codes are back. Time to replace it.
Interesting break down. It's cool to see what's inside. I liked the voice overs too. Thanks for keeping us straight.
I love your approach. Skillful, Sarcastic, curious and in some ways philosophical. It's much appreciated! Thanks for quenching my curiosity as well.
Ps: know where I can get a cat for a sulev accord? I'll pay ANY amount for a new one, but I can't seem to source it 😢.
Thanks brian. at 8:41 it looked and sounded eerily like a Big Foot might cross in front of your vehicle. Darn no luck this time...
Awesome video. Now I actually understand that my P0420 code probably is a truly bad converter.
Cruise Control defaults on these earlier Subarus anytime the CEL is on. I think it's a "safety" thing.
Could be. Still crazy.
Adam Alsnayyan - sounds right. On my Toyotas I always get the Traction Control Light and the Vehicle Stability Control (VSC) lights to come on when the Check Engine light is on. Three separate yellow lights. Great video Brian. Thanks. P.S. - be more careful with that grinder! Hate to see you get hurt.
Thanks, think this made me fully understand that I most likely have a clogged CAT. Audi B8 which had piston issue causing oil leak, that was fixed but it seems the oil leak may have caused the honeycomb to burn out & get ashy in the CAT.
Brian, in the opening with the machete, well it's used in automotive service the same way my wood splitting maul does, as an extra too... My maul has seen more metal than wood I believe, the back make for a great BFH!
Great info. Just replaced both of my cats on the same car. Now its on its face with a p0420 code only. Probably half my power is gone. Im lost. Scanner tests MAF and both 02 sensors ok as well as fuel trim. Another mechanic told me I now need to replace them both with CA cat's as it used to be a CA car >< this doesn't make sense to me
Mines plugged in my 2008 doing it tomorrow!
What an excellent video. Explanation of how the catalytic converter works and cutting it up so we can see what’s inside. Very good...
I only use the zip cut brand.Cost more but safer and last 4:1 .I have had a few buddies take stitches from them one got over 30 in his wrist
I'm sorry, I may have missed it in the explanation, did you explain why this particular cat failed ? I ask because I have an Aussie 2005 Mitsubishi 380 ( Galant in the U.S.) with 356000 klms. It has an east-west 3.8 V6 and shows both banks below threshold. I know she's cooking oil probably via the valve stem seals and that's most likely why my cats are screwed. But aside from a constant engine light the car's running great. Honestly, I can't justify the cost of two new cats unless I rebuild the engine and I keep getting told NOT to just redo the heads. Anyway, the point being is that I couldn't just chuck on a couple of new cats without addressing the issue that caused the failure in the first place. Not only for the cost of the cats but the huge job of removing the cat from the rear bank.
Great video and thanks for going so far into the can that holds the honeycomb. I reckon mine must look as least as bad as that.
A simple hammer knocks out the catalyst. In states that do not check tail pipe emissions, its a cheap fix. Not recommended, but works well.
I may be stupid buttttttt, it the REAR CAT is receiving tooooo much hydrocarbons causing overheating - then doesn't that have be jacked up from the FRONT CAT sending shit downstream to the REAR CAT? Does this vehicle only have one, two, three or four CATs - you have upstream and down stream bank 1 and upstream and down stream bank 2? How do you know the engine management and electronic ignition (TPS, MAP, MAF) is giving correct input to burn efficiently? I guess the answer is the upstream sensor would pick that up. I am not saying you are wrong but aren't there a few tests to confirm there is nothing else wrong - evap purge valve and will the evap purge valve stuck open cause 02 sensor to go bad - did you check the O2 sensors up stream? I was an aircraft electrician for 22 years so I have experience since almost every system on a car came from aircraft - doesn't make me an expert just asking questions cause I got a 0420 code - but the idiots at grease monkey didn't put enough oil in because they had the rear of the car lifted on the ramp so it indicated full when we got the oil light it was 2 1/4 quarts low - seems that oil change and car manufacturer with engine light at 2 1/4 quarts low coming on is a problem but I am wondering what it did to the system - O2, CAT because the 0420 code set not long after the oil low light and there was baked on oil on the dipstick and smelled burnt - I put Lucas engine oil treatment to help some and I am wondering - will a sea foam engine treatment a couple times - and a fuel cleaner several times do anything to clean the CAT or O2 sensors? Is there a way to clean cat on vehicle?
Thanks for the Video. I am getting the P0420 also, my O2 bank one sensor is steady while the bank 2 sensor is all over the place, have a hard time believing a 2013 vehicle needs a new cat!
I'm assuming you took it to the dealer. What was the diagnosis? Which car?
that is revealing how you're in a bad way when they get crumbly. I have now a 3" tubular converter made by thrush. It takes all the hypo carbons and converts it to sound. The pimple faced kid at the auto parts desk explained it to me
+Albion Laster Wow. I wish I could take him under wing for a few weeks. I worked at Autozone when they were a privately held company and witnessed the destruction of that business model by share holders relating to such phenomenon. I used to have time scheduled to train new hires- then they cut everything except "plan-o-gram" time wherein we transformed the place to resemble a cleaner version of a Tijuana street shop. We packed the isles full of plastic car junk from China while one poor soul frantically ran counter and told people whatever the hell it took to get them to buy and move on. All this because the owners daughter got cancer and didn't have the time/need/money to care for family and the business. Nuts. I'm always curious why things break down. My head can't let go of something till I have answers. Everyone is that way to some degree. Sometimes we accept filler material as a substitute so we can cope. It makes us comfortable till that information fails us when we try to use it.... like so much Chinese plastic car junk from Autozone.
Soooo.. many planos.... make them stop.
Bro great job cutting the cat that saved me a lot of explaining to the costumers lol
21:20
the diagnostic methods are the most helpful.
Why didn’t you put the heat shield on the new pipe, it came off easily.? That’s half the job and with the book rate you are charging it would more than cover the time required....just saying. Interesting video!
The voltage you were looking at in the video what sensor bank/location was this? Trying to troubleshoot an issue on a 09 legacy. I replaced the o2 after the cat and still having troubles. The car seems very sluggish and does not want to accelerate at highway speeds. Had a p0420 awhile back but it hasn't threw the code again in awhile. Was considering changing the pre cat sensor (the air fuel one) before trying a new cat/exhaust manifold.
It's the signal wire on the after cat O2 sensor. It sounds like your cat honeycomb is plugged up or melted.
What brand is that new cat (it looks really nice), I'm having the same issue with my 2007 Impreza with 200K miles on it. Awesome video, thanks so much for recording/sharing!
eddiejclayton1 2006 Impreza orbs with 200k. What did you figure out? I have lots of stuff in my amazon que: gaskets, o2 sensors, cataclean, new headers/cat, 02 debunker. Torque wrench, pb welder lol jk already had that. Thinking about going down to one cat. What was wrong with yours? Did you dissect it?
My ‘01 Forester has this same P0420 code and so do a lot of other ppl in the forum.. Is it actually safe running without the 2nd Cat? I might just do a 2nd Cat delete.. Will the code still show if there’s no Cat?
I’m actually amazed at the construction of a Catalytic converter..
Thanks for the video Brian!
I didn't catch the Scotty Kilmer reference, except when you showed a photo on the side like he did. I did notice the DeWalt and Hitachi tools and appreciate the 'just say no to Harbor Freight tools.'.....they creep me out. Buy there, and be ready to buy it again. I have good tools from over 2 years ago, that won't happen with Chicago Electric. Stop buying Chinese shit.
Subscribed! That was a thorough review for my Toyota. I was clinging to not believing it was the cat but didn't want to throw a bunch of parts ten find out it was the cat. I think my Corolla has this same manifold cat in addition to below, nice to get confirmation. I'm going to try running w/o the upstream sensor, I wasn't sure if you could do that.
I'm sure your view count means much more to you, but those cats are sooo valuable! I hope youtube pays more than the metals are worth.
Thank you Brian. Very interesting. Your videos are always entertaining and educational.
I’ve been researching aftermarket cats for my 2008 Legacy, and unfortunately the general consensus seems to be OEM is the best bet if you don’t want to replace it in 4-6 months, I’ve seen 2 or 3 now that all said no more aftermarket cars only OEM, something about the aftermarket ones restricting air flow and just not lasting. Any recommendations for reliable options that aren’t 1700 bucks, I may just try to find one either way a blown motor and buy it just for parts and the cats, I need total exhaust it’s all rotted out.
Hey great video just got a p0420 on my 08 suabru impreza. I determined that yes my cat is bad but my question is can you tell me what caused it to go bad. Cause I dont want to change the cat for it to go bad in a year or two. Is this a common problem for my impreza?
hello from stormy Ireland. idea about taking the sensor out to feel for cat blockage is something I'll remember 😉
Hey man, love your videos, thank you! Working on a 02 llbean with 200000, not sure if cats ever been replaced, but it’s throwing a very intermittent po420, cleared on its own. I don’t have a live reader to check 02 sensors, and I don’t just want to throw parts at it. Subaru said it’s pretty straight forward on the phone and said it’s the cat.. where should I start? Would o2 sensor be intermittent or would cel stay on? Any advice would be huge. Thanks boss!
Did'nt realize the cat was that small. Was well clogged up and well diagnosed.Big difference in the reading of the rear sensor when new cat was installed.Computer was on target with the code. Can't whack the post mortem to confirm the reason for the code.
Thanks for sharing your knowledge!
How many miles was on the converter? is there a typical life span? I've got the code - and now a little knowledge thanks to you
Had a P0420. Replaced both O2 sensors. Nothing. Dreading replacing cats. Engine was running like crap and still putting off cats so took it in to a subie specific shop. They cleaned out my throttle body and reset the cpu. 0420 gone going on a month now. So check that throttle body : )
bad failing MAF will give you that code too,made the car run wrong and cat couldn't warm up enough
As long as your check engine light is on the cruise control won’t work. It’s a safety feature
Thanks for doing this! I know I asked if maybe you could go over this a while back and I think it helped me... now I know I need to drop all my money on a new cat.
For an 02 forester, what brands or companies do you trust enough to recommend a new cat?
Mines toast I'll be having to switch mine out, very good video !!
My 06 forester 2.5X always disables the cruise control when there is a check engine code. Pretty sneaky...
Great vidjea! This happened to my 04 sun fire. Car wouldn't rev past 3500, cat was all broken apart and blocking the exhaust like you mentioned. A sawzall fix it!
Did you replace the gaskets when putting in the new cat? I know you said you were holding the one on with your thumb. Thanks!
What can happen if I use a gallon of lacquer thinner to a quarter of a tank of gas. So say it can clean the catalytic system if it's not to far gone. Should I try it.?
Out of curiosity, were you not worried about inhaling that stuff without a mask on?
No, why?
Hi Brian, great video and great topic, keep up the good work. Also just want to ask why is it that this video is in 480p? most of your other videos are in 1080p. thanks
Dude your beard and your videos are on point.
I got a 2011 Chevrolet Traverse i just bought with 222k miles. Test drove it 3 times before i bought it and ran fine every time. Had a 40 min drive home from lot and about 30 min in the rpms started to drop. I took it to auto zone and got it tested for free and they said it was a bad catalyst system low efficiency bank 1. Told me to try Cadi clean but they was out every where so i got a diff brand and it took the check engine light off but it still ran like shit. Put it in a shop and they charged me almost a k to replace the first one. I get it back and drive my wife to work that night and it does the same stuff. Took it back to auto zone and it pops for the same thing. Do you think it a bad o2 sensor or converter that is post to be new. Cant get no one to answer my call at the shop in 4 days. Also if it is o2 sensor are they required to fix it for free since they misdiagnosed my car. They even told me it was the converter.
Just take out the fuse 7.5 for a little bit and put it back your codes will be ieraser
Hello, I live in Drfting, PA, I was wondering do you do local repair work? I have a 2006 outback, died on my way home from work, I think it is a broken timing belt but I assume that means more damage was done internally when this happened, well that is what my husband thinks, I was wondering if you do those kinds of repairs? Thanks Carrie
Excellent video, as always! Also relevant to me as well, as my jeep is throwing a code about my cat.
So with you down south now, you hitting up Brian's Head? I'd love to board some mountains surrounded by red rock. Also, you ought to make something nifty out of that old cat! The way that thing melted is almost artistic.
I have a bluetooth FIXD device, not a full computer output I guess? It tells me that the Oxygen sensor has has failed, the Evap system has failed and the Catalyst system has failed (and emailed me the P0420 code). my battery went dead it also tells me I have insuffient miles, might the problem go away with just driving around some more?
my daughter car also has the Cruz control issue.
Brilliant! Thanks for taking the time to explain!
Dang, the old cats are worth some $$$ in scrap.
Had a P0420, the cat had a small ding from the car bottoming out. Pulled the cat and there was absolutely no material left inside. Blew it all out the exhaust once damaged.
Hey Brian. Will installing a cat without a heat shield cause you issues down the road?
At the repair shop my 2010 Ford Sport Trac, 2WD showed a check engine light PO430 cat converter inefficiency error code. The car had a few symptoms: reduced gas mileage (16mpg to 12mpg), loss of acceleration to take off from a stoplight and continue up a hill with good power. Should I start by replacing the O2 sensor? I had the antifreeze flushed and filled and the shop did not find any leaks, but the reservoir was low. It has been bitterly cold.-- I am not sure that I want to replace the cat converter until I know what caused it to fail.
YES IM GLAD I TUNED IN! lmao thank you, sincerely me and my struggling subaru
Hey, Brian, using the non-contact temp probe, what is an acceptable temperature differential between the inlet and outlet of the catlytic converter? I've heard about 100 degrees, but wondered if this still holds true. I know it varies, but was looking for a general range. Thanks!
Your video is great! Your personality is awesome and I dig all the hidden jokes in the there - plus I'm learning : ) High five buddy!
why didn't you put the old heat shield onto the new cat? I'm guessing it wouldn't fit.
+Nick Pelletier Yes.
briansmobile1 thank you for the reply. It seemed like the only logical reason.
+Nick Pelletier damn, I wanted to ask exact same question :D