P0420 Code. How to fix it. Don't spent spend tons of $$$.

[@FixingWithPassion]

Rare Occasions the O2's and Catalytic Converter's Go bad...VERY RARE. I have found starting with small things like, Gaskets, Air leaks, make sure something has not come loose, etc...usually has a better out come than spending $ 100.00's of dollars on Catalytic Converter's ETC. Take it one step at a time.

[@thomasmarquez6790]

As a auto tech 80% of the time it is a converter.

[@fury3600]

very often.... very often. hit a bump, shit breaks. gut the bitch, do the antifouler trick, never gotta deal with that shit again. this may fix it for a while until the p0420 pops up again, it takes a long ass time for it to show up again as the evap system is the last one to go through clearance. but i guess people like hearing false hopes than the hard truth, which isn't for the weak-hearted

[@khemicalgoddess4614]

May i ask what may be loose so i can check off the possibilities..thanks much great vid

[@chrisdeforce1]

Nathan Rohrbough can you leave links to the required parts

[@deanshoemaker5618]

@@fury3600 spray starting fluid on the vacuum line's or anywhere it could leak be careful but if there is a leak the motor will rev from the starting fluid

[@riverviewvineyard1143]

Check the easy stuff first, I just solved my P0420 found a vacuum line off. Got to get lucky once in a while.

[@FixingWithPassion]

Lucky you!

[@riverviewvineyard1143]

@@FixingWithPassion Your doing the public a great service, keep up the good work. All the do it your selfers out there appreciate your input. Truely

[@davidweum9334]

Good for you. What unit did you use. I'm looking at buying an Auto...somethig for $124.00 on sale.

[@The_R-n-I_Guy]

Exhaust leaks can also cause a oxygen sensor/catalytic converter code. And usually if you let it go too long you will have to change the sensors after you fix the exhaust leak. Because your engine will run rich and flood the oxygen sensors and foul them out

[@FixingWithPassion]

Yea....not good

[@shadowman1992]

Need advice help please. Code p0420 car is not burning oil and is running fine obd2 scanner also says poor connection sensor 2 and pcmm could the issue be my down stream 02 sensor ?

[@carlosmunoz7934]

You are so right ! I had the code and it cost me nothing 13 dollars for a gasket , just like you said ! Thanks

[@FixingWithPassion]

Nice.!

[@iamlazarow3526]

Which gasket?

[@americanpatriot6038]

Your 100 % right ,not knowing i was younger had that code autozone guy said its o2 sensors i have 4 100000 miles ill replace all 60 dollars each code came back in 24 hours ,had a mechanic friend tell me look for a vacuum leak i did 3dollars fixed problem rubber vacuum line laying on hot engine melted hole .now i tackle everything differently. GOOD JOB.

[@frankbarker1568]

Check for vacuum leaks

[@glasser2819]

salesmen are rarely good advisers 😉

[@nofortunatesonII]

My 1999 Ford Ranger 3.0L 5 speed manual 2WD had the PO420 code. I replaced the pre-cat O2 sensor (passenger side) and the check engine light has been out for 5 years and still good. I purchased an OEM sensor (made by Bosch).

[@luisponce1472]

Where did you buy the Sensor?

[@nofortunatesonII]

@@luisponce1472 I think it came from Auto Zone, but was a Bosch like the original unit. Been many years since replaced and code has not come back.

[@shaunsmith9526]

Both my cars had P0420s hit at the same time. Did the full diagnostics. Ended up replacing the Cat in my Tacoma and as of 1 month later, no more P0420. I checked and replaced the intake gaskets with no success. On my Grand Caravan it turned out to be a bad gasket in my air intake plenum ($16 gasket). Don't discount a bad cat - it does happen.

[@FixingWithPassion]

Yea more that often ;(

[@christophersmithey1490]

Awesome! Got a PO420 code and ran across your video after about 6 others who never mentioned a loose line. Checked under the hood...cracked hose. Thank you!

[@jonmo2694]

What hose?

[@randomrebuilds]

Great piece of advice. My friend has a 3.8 Firebird with 50k and she has that code, however the car only has 50k on it, so I will relay the info over about the gaskets or vacuum lines.

[@nordicpride9708]

Good video. From experience its my opinion that most DIY mechanics need to invest in higher quality scan tools. If you drive an older car and or work on a lot of OBD-2 equipped vehicles the simple code readers are next to worthless for diagnosis. They simply give you a code. I use X-tool but Autel, Topdon and countless others make dealer grade scanners that will simplify your diagnosis process.

[@FixingWithPassion]

Update to this video: After fixing the intake gaskets the p0420 never came back on (perhaps rare on this fix and a 2nd 4.6 ). Perhaps air mixed with antifreeze tripped the code... a bit strange tho. If this is not caught soon, it will burn up the cats!! But if all else is ok, fuel trims, no other codes etc, leaks then cats probably are bad. It does happen sometimes. Tap on the cats to see if you hear rattling, if so they may be falling apart inside. Scope them and watch graph to verify. Happy fixing!

[@joseguzman5807]

I have this code on my truck, but I don’t know why the check engine light turns on and of every week

[@leetos.4915]

If you hear rattling while tapping the cat underneath, is that a solid indication to replace the cat asap?

[@jbraun0ekrep]

Thanks Nathan. Great run through and information. Got PO430 on 2015 Infinity Q70. Qoute from dealer $4,200. Rediculous!!! Will be checking for leaks. God bless.

[@FixingWithPassion]

O MAN!

[@prestonworden9811]

Try Cataclean or something like that you’re car is rather new

[@joshh9003]

I can’t thank you enough for the explaining I have a 05 Buick lesabre with the 3.8l v6 with the plastic plenum and there’s antifreeze leaks around it so that’s proly y my code is coming up I’ve changed the 02 sensor spark plugs and wires and ICM and all 3 coil packs and that dang code still came up so now I’m gona fix the gaskets before I tackle the Catylic converter!!

[@almirlimaj4354]

I have a 2012 Honda Accrod 4cyl. I got the same code, so I have replaced both O2 sensors and a Catalytic Converter, but the code is still there. I'll need to check for leaks now. Great video. Thanks!

[@abe5316]

What did you find after..?Thanks.I think lot of Hondas and royota have that code and toyoto and Honda need to help recall those product but people need to revolt against those two companies.it costing people lot of money but no one is talking

[@iBeTheRealWill]

@@abe5316 I Have A 03 Honda Deleted My Cats And Its Still There

[@selahveee]

did that fix it?

[@W3BZSL1NG3R]

When you use a digital temperature gun. A BAD catalytic converter will be hot going into catalytic converter & cooler coming out. A GOOD catalytic converter Will be hot on inlet & even hotter on the outlet. Hope this helps

[@FixingWithPassion]

Yes thanks!

[@W3BZSL1NG3R]

TVWXMAN32 Np Did you ever put the gaskets on? I had a, 2000 4.6L towncar And had to replace plastic intake and gaskets @120k I Bought the 1 owner car for $3k With 70k miles. Sold it with 390k miles For $2.5k last summer and she's still rolling. Changed oil every 2500-3000 miles And beat it everyday lol 120mph governor :-p. Cya, W3BZ

[@FixingWithPassion]

Yea I did, I have done 6 since then...lol

[@W3BZSL1NG3R]

TVWXMAN32 I ask, Cause you said you'd post a link In description Of a vid update. K keep up the great work on you're channel. Well cya, W3BZ

[@jrblaxxx2340]

Yep you're very right

[@leoguy1609]

If it's your Catalytic Converter you can often reset it long enough to pass inspection, was able to do that for nearly two years. Finally had to change it when emissions would complete a cycle. Mines was factory original from 2004.

[@FixingWithPassion]

Yea but....Emissions testing places are on to that. Until the vehicle/system clears so may start cycles, your not really passed and any emissions. Only after all start cycles are completed and the computer see this and is happy. There probes /computers will see that. Been there done that.

[@Bowhunter-ft8cn]

Thanks for this. I just replaced my intake manifold gaskets and got this code shortly after. It was a new code so I was thinking something else went bad or I broke a connector on the O2 sensor or something. After you stated a vacuum leak can cause the p0420 code I went back and checked everything and found I left the vacuum line from my throttle body disconnected. Put it back in place and the code hasn't come back so far. Thanks for the information you provided.

[@leetos.4915]

I feel it's also my manifold gasket on my hybrid and checked with my mechanic and said it cost about $500 to do the labor...how many mileage do you have on your car? I'm at 240K mileage at my 2017 Hyundai due to Ubering full time

[@1redrubberball]

My 2003 Chevy Trailblazer with 217,500 miles on it, turned on the "check engine soon" light, with the P0420 code. In my case, a new air filter and a can of Seafoam in a fresh tank of 89 octane Shell midgrade (no alcohol), did the trick. The light didn't go out on its own, so I cleared it and drove 106 miles today. It remains off. Tomorrow I'll get it inspected. I did a lot of research and anything that can upset the fuel/air ratio, can cause that code! Check the simple stuff first! Good luck!

[@iamlazarow3526]

Has the light remained off?

[@1redrubberball]

@@iamlazarow3526 It remained off for at least 6-9 months.

[@szzpawnkntrl2018]

Thank you so much for the time you invested! You saved more than just my day😅

[@ralphwood5114]

Good information.I recently replaced the engine with with a Japanese import engine on my 06 Altima. The engine came with a plastic intake manifold. The original. Was aluminum. I have no idea why the aluminum one has shutter valves opened by a vacuum motor and the plastic one has none. I went with the aluminum. The engine runs fine now but had so much soft carbon in the intake it was causing misfire which I was blaming on on something I did wrong. I think it just needed some normal driving.

[@FixingWithPassion]

O yea? Hummmm

[@islandbeaches395]

Right Nissan Sentra have plastic intake and I discovered a crack by the end of the throttle where it bolt up. I have the same issue but went ahead and replace the converter since the car have high mileage.

[@FixingWithPassion]

Nice!

[@RamxRamx-fw3gm]

That is awesome information! Hope my Honda Pilot gets fixed by doing this. Thank you.

[@FixingWithPassion]

Sweet!

[@testtester9539]

Solution starts at 3:25

[@ryanchacon2005]

thanks for this man, i was worried until i found oil leak from driver side head cover creating oil burning smell and throwing this code

[@Supesfan88]

Hey there, old video, but! I've had a P0420 code on my GD car for a year. I've replaced the up/downstream O2 sensors, fuel pump, Valve cover gasket, etc. After replacing the VC gasket and fuel pump the light went off for a glorious 2 weeks. Came back on today - P0420 code again...gonna look into this manifold gasket next. I really don't want to put a CC in a 10 year old car with nearly 300k km on it. No matter how much I love it (I call him Speedy Gonsales - 2010 Chevy Aveo :))

[@alancameron2433]

Did you get the P0420 code cleared?

[@Supesfan88]

@@alancameron2433 Nope. but DEFINETLY the exhaust manifold (w cat). I'm going to use my multimetre on the o2 sensor attached to the manifold to see if it's faulty as well (or useable when I replace the manifold because O2 = expensive, dammit!

[@alancameron2433]

@@Supesfan88 I have watched some very interesting You Tube videos regarding code P0420.The more you watch the more easy it will be to diagnose correctly.

[@kellyokamoto1604]

I have that EXACT Expy-same year, engine, etc. Even same color! I had that P0420 code about a year ago, reset it, and it never came back-YET. I DO have the "Evap Sys" test not complete. I've been trying to trace that problem for a while and can't seem to find the leak. Had a shop smoke test it and they said it "could" be on top of the gas tank, they'd have to drop it, and it'd cost a minimum of $700.

[@markchidester6239]

Go somewhere else

[@roscothefirst4712]

This video saved me a significant amount of money, been trying to solve this P0420 code on my 2009 Ford Flex- tightening the manifold bolts and checking vacuum hoses solved the code issue.

[@ThatBoyMichael1]

How did you use to check for vacuum hoses?

[@msntung]

@@ThatBoyMichael1 probably with water and soap

[@shawnt1206]

@@ThatBoyMichael1 - You can use smoke also to find vacuum leak.

[@worldpeace5853]

P2279 is for vacuum leak via intake manifold gaskets under the hood. P0420 is for the check emissions systems. I am not sure why vacuum leak is the issue? I can understand if there is an exhaust leak though. Not sure if I am seeing any relation here???

[@FixingWithPassion]

Yesterday...P0420 code found, a pin hole in a head gasket. Boom! Replaced it...no more P0420 code;)

[@warriorspirit9113]

Your a life saver man. You Thanks for the post

[@valdesadam]

I have 2 vans with this style of gaskets. They are easy to fix but they have a lot to take off. I dont want to do the work again! I just got one done and the second van started to act up. Lol Thank you for the video.

[@robertsimpson4984]

I solved the problem with some silicone grease ( from the pool store) on the Gas Cap “O” ring ! A 50¢ fix !

[@robertsimpson4984]

Now time to buy a new gas cap “O” ring for $8 or a new cap and “O” ring for $35. I’ve had it come back on 3x and it went away when I put the silicone on. It ALWAYS GIVES ME A 420 code if I don’t put 7 clicks in the gas cap when putting the cap back on !

[@NewLevelAuto]

I'm afraid you must be mistaken . A catalytic converter has nothing at all to do with your gas cap . Two different systems altogether. The evaporative emission system is responsible for storing and purging fuel vapors and will set codes like p0441 p0442 p0446 etc. But will Never set p0420

[@robertsimpson4984]

New Level Auto thats what I thought too... but I found a small note like this on my search on Utube and thought I would try it ... it worked!! And since then if it comes back on I just go give my gas cap 7 clicks and reset my codes and it goes away ! STRANGE but TRUE !

[@adrianapollyon5087]

He had a p0440 code. Not a p0420

[@smid2550]

@@NewLevelAuto right - it should have been a fuel system leak.

[@jeffk3776]

If you get this code on a 1.6L Kia Soul, take it to the dealer to execute the latest recall. They will reprogram the ECM, and will probably replace the catalytic converter.

[@calvillocobra98]

I got a 2014 kia forte 1.8 just replace the converters and the cam shaft sensor and the crank sensor and the stupid light keeps on coming back

[@Ginnito]

@@calvillocobra98 what have you done ? Am having the same problem

[@calvillocobra98]

@@Ginnito never fix it sold the car

[@Ginnito]

@@calvillocobra98 guess that’s my next step ! Thank you 🙏🏽

[@calvillocobra98]

@@Ginnito no problem man i think the problem was oil sludge

[@andrewflores4981]

Bought a $20 micro mechanic from Walmart. Used the torque app to clear the code whenever I get it. Comes on every now and then but not a big deal. Everything’s good as far as I can tell.

[@FixingWithPassion]

Make sure the bearing wax seal is still good. They fail.

[@AikidoTubeSock]

What exactly is "a can of spray"? I know what a spray can is. What is in it?

[@joseph2095]

I think it's something combustible. Propane gas, or maybe starting fluid...so it gets sucked into any intake leak and raises the RPM.

[@3dmundCheah]

Brake cleaner will do the job. Just keep out from spraying the alternator side

[@AikidoTubeSock]

@@3dmundCheah Got it, thanks.

[@frankg6578]

@CHARGING FORWARD Why is starting fluid best?

[@angelhoyle9376]

I have an 06 Ford Escape, my check engine light came on a week ago. took it to nearest auto zone and the PO420 code came up(that’s the only code), I’ve taken it to 3 mechanics and they all say it’s fine to drive but the whole catalyst converter needs replaced. now my Ford Escape has 3 converters on it fml so if I don’t have to have them changed that’d be great. However my question is will these seals and alittle extra air getting through cause my vehicle to sometimes have trouble starting and terrible gas mileage?? Or is one of my converters actually bad??

[@dominiquelewis1871]

i just changed my temp sensor gauge and that code came up, do you think may not be tight enough or did something else go wrong?

[@Perrin2401]

Same... I’m not sure what happned

[@f4tc0w]

You would have a p0171 if you had a vacuum leak. PO420 usually means bad catalytic converter. You can monitor the voltage of the downstream sensor and if it fluctuates with the upstream sensor you have a bad cat

[@northernswedenstories1028]

Came here to say this. I think this guy has it all wrong diagnostically. P0420 is almost always the cat that is bad if there are no other codes. If I also had a lean or rich code then I would suspect air leak or fuel delivery. But p0420 on its own is a clear indictor to suspect the cat. Confirm by testing pre cat and post cat o2 sensors for mirrored air flow patterns.

[@TheNYgolfer]

Well put. Thanks. My downstream sensor stayed pretty steady at about 0.8 V. The upstream sensor did not fluctuate much and stayed around 0.5 V. Besides the P0420 code I also got a P0133 code. Upstream sensor slow to respond. Going to replace upstream O2 sensor.

[@newguy1459]

I can't wait until you come out with the new video in step by step and in detail of how to solve this problem. I need to fix my p0420 problem.

[@escarsegat]

well you need to listen to the video

[@escarsegat]

spray water replase gaskets whats so hard about that you a man figure it out boy get off your ass

[@MrFlargas]

@@escarsegat You're an idiot

[@Kevin-wy8kc]

took the words right out of my text nut butterson

[@ddroppa101]

@@escarsegat 😂😂😂

[@Meleeman011]

best diagnostic tool is your ears. hands down. I saw p0420 and i replaced my gaskets on a toyota sienna, and it ran much better when i replaced intake and throttle body gaskets, although it runs a bit rough on high way speeds which doesn't make sense since the rpms are lower than when getting upto speed. my guess is worn suspension parts, but they are certainly still good. the last thing i know is a problem is probably oil in the cat, since it has been running rich and blowing blue smoke before i replace 02 sensor.

[@FixingWithPassion]

Nice!

[@chrisduhaime5689]

The propane test around the intake. Or break cleaner . Light spray around intake and vac lines .change in sound and speed your getting close.

[@jeurecollado6409]

Wouldn’t it be better to put it on the upstream O2 sensor instead of the downstream? I used an infrared thermometer to measure the heat before the upstream O2 and after the downstream O2. The heat read about 530 before the upstream and abt 350 after the downstream. Pretty rock solid proof the cat is bad. What do I think?

[@thomasbooker3829]

Check out Scotty kilmer channel on P0420 code using 1 gallon of 100 percent lacquer thinner, to half tank of gas and run engine at 2500 rpm for 30 minutes, or road trip for 80 miles or so to burn out carbon in cat. Excellent old-school mechanic !

[@Spacepilot616]

Scotty does not have reliable info

[@ripptydevibes2581]

I completely disagree! Doing this full time for 15yrs as a shop owner, a simple "live data-fuel trim" check will immediately expose an "air/vacuum leak" and MOST of the time this is going to trip a lean code. With your insistance of lean issues you dont even provide us with a fuel trims check?? Thats like taking a misfire code P0301 and saying its usually always an air filter.

[@JB91710]

If you get codes like that after your battery has died or been changed, run a vehicle specific Drive Cycle. That will allow your computer to get in sync with the sensors.

[@oldsmobileaurora7418]

How big of a deal is the extra air going into the intake manifold? Because I just replaced my 4.6 2v with a aftermarket dormant intake and the code came on after driving a few hundred miles.

[@arielrodriguez6980]

What do I spray with to find leaks?

[@Yahs-our-All]

Thanks for sharing your experience and knowledge

[@FixingWithPassion]

My pleasure

[@496elcamino2]

After I changed the plastic intake 2004 lesabre I got this code. I’ll check for a leak. Hope it’s it, thanks, great video and help.

[@FixingWithPassion]

ok

[@leordo11]

If you have un metered air or air leak the computer will set a code p0171 or p0172 system to lean look at your fuel trims then you will know for shure.

[@cooterpolluter]

Recently changed my intake hose because it was cracked. Likely have another leak. I will check.

[@dougyjones8704]

Will it pass the smog check

[@uawsux]

If you want to check if you have a vacuum leak take a propane cylinder with the engine running a long hose on the nozzle and shoot propane out of your little tank you're settling tank soldering tank down along the edges of the intake manifold around your Christmas trees around your diverter valves around your bank vacuum switches and if your idle goes up if your idle goes up that is where the leak is

[@FixingWithPassion]

Good tip ;)

[@toyotafan83]

I had a 2000 ranger that i replaced the upper intake gasket on but the code was something like system too lean bank 1 and 2

[@FixingWithPassion]

Nice!!

[@teejay9429]

I got this code on my Honda accord 2001 v6 cus I cut the cat off and straight piped it. But I kept the mufflers.

[@FixingWithPassion]

Right on man!~

[@dennyhao4027]

My old volo xc60 runed 130k miles and used no.87 gas for it.recently it appear engine check mark and went auto shop paid $200, recommended to change 4 oxygen sensors and cab. total amount will be $5000 more. And talked with the shop owner and found some useful info. ---use cabcleaners for 3bottles running 1200miles. The engine light gone. 😅

[@FixingWithPassion]

Nice!!

[@handyman2233]

I been noticing sulfur smell and finally got the p0420 so these don't apply to mine. The cat on mine is just going bad. I might try and clean it but might just opt and get a new one.

[@MysticMagickery]

Seems to me like that’s what’s happening for me I don’t know much about cars period and now that I’m in the position with this, code every place I’ve been wants to go by the code instead of helping me to solve any underlying issues... or really look at anything else mines a 2008 Honda Accord v6

[@FixingWithPassion]

Don't shell any $ until someone is willing to help you to trace down the issue.

[@reneescarcega7263]

I have the code p0430 on a 06 honda accord v6 , did you solve the problem? ?? How? What was it?

[@ShakaBroski]

I’m dealing with the exact same thing right now. They all want to jump directly to replacing the cats 😞

[@Dewey_Boondye420]

now when you say check your gaskets. i have a valve cover gasket causing an oil leak, could this possibly be at all responsible for the code? or do you mean other places? sorry, im not the most mechanically inclined.

[@FixingWithPassion]

No.

[@Dewey_Boondye420]

@@FixingWithPassion i ran through 2 bottles of "caticlean" i was going to replace the sensor.. but it being an 04 tsx for some reason the cheapest sensor was over $400 im assuming the sensor may be fine but im wondering.. is my cat okay, or do i probably just have an exhaust leak somewhere? i seen a video where a guy just sprays soapy water all the way from cat to exaust until bubbles are seen to find the leak. could i just do that & slap some jb weld on the leak??

[@qward2174]

@@Dewey_Boondye420 kzbin.info/www/bejne/mWe0dmeaiK-lqpY

[@gibson7654]

Hello. I'm getting the P0139 and P0137 codes. I have also noticed that there is no voltage coming from B1S2 at all. Is it safe to assume the sensor is bad?

[@Drybones195]

My 2006 Honda Civic just gave me this code. It has 234,000 miles on it. Is it more likely the O2 sensors are bad, the converter is bad, or both? I noticed when it’s really cold out that it would have trouble shifting at first but then it would drive fine as the engine heats up. I also noticed my gas mileage has dipped a little bit.

[@FixingWithPassion]

Check obd2 data. Make sure o2 are working Graph them. Graph the cats also. They should look lazy on the graphs almost a straight smooth line depending on the RPM.

[@Drybones195]

@@FixingWithPassion Cataclean cleared the code. Not sure what was wrong or if it’s fixed, but the check engine light went away.

[@Sprecial-jr3qg]

Hey, I got an Explorer '13 and the water pump was leaking outside the engine. After I fixed that, my mileage tanked during city driving (stop-and-go stuff), but no check engine light is on. My OBD2 scanner's showing a P0430 code, though. Any ideas? Just so you know, it does good on the highway!

[@kidnplay2148]

I have a Chrysler 200 2015 and I got this code I’m scared to take it back to the dealership to fix it because every time I take my car to them to fix a problem they fix the problem then the check engine light comes on with a whole different code I waisted a lot of money just for them to fix one problem and then make another 🤦🏾‍♀️🤦🏾‍♀️☹️

[@MustangGuy1996]

My 2011 mustang 3.7 has p0420 was causing power loss and misfire but only when DECELERATING. When accelerating only slight power loss, no misfire. I replaced the bank 1 o2 sensor and catalytic converter (when i removed the old cat it was full of broken pieces inside.) the code hasn’t come back yet but the symptoms are still the same with the replacement making seemingly no difference. Just did my plugs 6k miles ago too..do you think it’s reasonable to conclude if the cat was blown on one side that the other side is likely the same?

[@emilyanderson3681]

Having oil leaks and low oil pressure on my 2001 Subaru Outback h6 and I just got this P0420 code. Any thoughts?

[@FixingWithPassion]

Yea, have a man look at it.

[@waynepolo6193]

Commented just a minute ago with an idea where you might look for truly helpful information. It’s disappeared now, and I can’t honestly be sure if it was an algorithm censor or the channel operator personally. If it’s the latter, let’s see if he’s ‘Man’ enough to leave this one up -- putting ‘P0420 gremlin and oil consumption’ into your search engine should be more useful to you than this channel.

[@emilyanderson3681]

@@waynepolo6193 okay. Funny I've had 2 new oil pressure switches put in to try and fix the flickering oil light at idle and it hasn't helped. Plus, it's supposed to be running at 14PSI when it's running at 7. Not good. Shouldn't be an oil pump but I have a bad feeling it's engine bearings going out. Sadly, I've only had this car since February and it was running great until lately. Damn Subarus and their oil problems. But I have a feeling the P0420 might be because it has a muffler delete🤷🏼‍♀️🤦🏼‍♀️

[@waynepolo6193]

@@emilyanderson3681 Jesus, what did that car do to the last owners for it to deserve that kinda treatment? Check the oil for metal shavings if the bearings are a concern. It could also very well be the lack of back pressure throwing the code, considering the muffler delete. If I had to go full Occam’s Razor, though, I’d say the most likely culprit (and ideally cheapest) is a leaky gasket is making it burn oil and clogging the cat. If you absotively posilutely can’t put a new valve cover gasket on it right now, slap some AT-205 in there next time you see the oil’s low. It’s not petroleum based so it won’t over-swell the gaskets, or bushings generally. Legend has it that a gallon of lacquer thinner in a half a tank of gas can clean the catalytic converter surprisingly well. Just don’t do what I did and try that out _before_ addressing the oil leak. Not a waste, I’d say… but certainly not efficient. Edit: also, I believe a gunked catalyst can affect manifold pressure. Check your PCV and your rear main seal.

[@emilyanderson3681]

@@waynepolo6193 yeah I think it was drove hard before I got it :/ But the interior and exterior are in lovely condition considering the age. Moreover, thanks for the helpful advice! I'm hoping I can make it last many more years 🙏 I'm sure I'll get it figured out somehow without having to take the engine out 😅

[@heatherrrenea]

What type of spray?

[@biglove1941]

I find vacuum leaks by Spraying water around the gasket while engine idling..if engine stumbles..you found the bad gasket

[@FixingWithPassion]

Nice!!

[@JesusMunoz-dw9ms]

I love the angry face. But the video is also helpful.

[@FixingWithPassion]

Nice!!

[@thecrittergitter7576]

Is this common on the 4.2L V6 F-150? I have a 05 F-150 223,000 miles.

[@historyhunter5215]

Nathan, this Nathan says Thank You!!!!!

[@toucan221]

looking at this in Feb 2021 never seen that before !! plastic intake, well one thing for sure, something new I've learned today. thank you Nathan

[@canyon.county208]

Lmao must not have seen many engines, alot of cars come with plastic intakes stock. My stock intake manifold on my 96 gmc is plastic

[@elijahaustin5253]

You could look at freeze frame data. If O2 positive could possible vacuum leak n if Negative leaking injector or stuck purge

[@FixingWithPassion]

I found that one time on a intrepid.

[@adrianapollyon5087]

So my 2003 nissan altim, which is running lean Short term fuel trim is up to 20% and ltft 10% ... I have P0420 code. . . Could it be a leaking injector? 🤔

[@rzjk301]

There are youtube videos on how to make a smoke machine out of paint cans. This will help you test for leaks in your intake and evap system.

[@FixingWithPassion]

Nice. Thanks!

[@keithupton86ku]

A can of brake parts cleaner is like $3 and does the same thing.

[@adrianapollyon5087]

@@keithupton86ku but it is invisible 💁‍♂️

[@keithupton86ku]

@@adrianapollyon5087 And? Guess what happens when you spray brake parts cleaner into your intake while the engine is running? It'll sputter and possibly die. The same thing happens when you spray brake parts cleaner into a vacuum line, or a leak in the systems(s).

[@jerrychircop7121]

Finding leaks is so easy with a smoke machine. I would have immediately gone with a smoke machine and if you have a leak there will be smoke. They have an adapter to insert the smoke into the throttle body. Thoughts?

[@FixingWithPassion]

Yea right true got one now days

[@ricardorodriguez-se7tp]

Hi I have a 2012 F250 6.2 P0420 when I turn off the engine I can hear a quick hissing on the manifold its plastic do you think it might be the problem Thanks

[@mikecrane6096]

The smog narcs in Kaliforniastan check your O2 sensors to bust you for using sensor extenders.

[@FixingWithPassion]

Word!

[@damacknificent151]

I recently had 420 code with check engine light. The night before i had swapped the battery for a new one. I think this caused it. I drove the truck for 35 miles and the light turned on again. I cleared the light called it a day. Next day i drove to the kids to school, once getting home i remembered i had the obd2 blue tooth scanner. I poped it in checked for codes and the emissions lights were green. I drove to smog check and the mechanic said you are ready for smog, and i passed

[@FixingWithPassion]

Nice.

[@Roller76]

Yes! Just4Fun. My car started running rough and felt like it was going stall. Then, out of nowhere a battery light came on the dash cluster. I thought my battery needed to be replaced so I had it checked and it was bad. So replaced the battery. STILL HAD ISSUES. So I replaced the alternator since it has a lifetime warranty. Well the battery light went off but a few days later the check engine light came on and hasn't gone off yet. So I had O'Reilly's run their OBD2 and it said it was the catalytic converter and O2. But even the guy there told me my catalytic was fine. But now I'm going to check all the hoses and seals. Thanks for the video

[@isrealperez9069]

At start up on cold engine smell a faint gas reved at 2500 rpm I can still smell but don't know where it's coming from my 420 come on 1 trip 1/2 so if I do have a leak can that cause my fuel trim not to work right

[@FixingWithPassion]

Mine was a bad injector leaking fuel /or stuck injector.

[@adamjoseph1970]

Nice video! Went to mechanic, they said my cat was fine but needed both of my 02 sensors replaced(which I did, both oem). However, I still get the codes! I have a 2013 Corolla S. I don't know for certain if the intake is plastic or not but I'll surely check asap! I also have a very small evap leak(p0456) but im not sure if that has any bearing on the p0420 code. Question is: Can the gaskets leak if the intake is NOT plastic?

[@FixingWithPassion]

Adam Joseph .....yes...my expedition is an aluminum intake and I've had to replace gaskets on them and for other people.

[@jonmo2694]

Use gumout or catyclean

[@billsteil8002]

po 420 code first change spark plugs a misfire will cause to much unburned fuel into the catalitic converter and also distroy the converter.the injector cleaner will help clean the injectors and the converter.Also check for a bad coil check eachcylender for misfire.Unplug wire if motor shakes thats the one.

[@FixingWithPassion]

Word! But a lot of times...its to late the damage has all ready been done to the cats. But you are right. That's why is always good fix a issue right away before it causes a chain reaction sorts.

[@mrdrv999]

@@FixingWithPassion that's what happened to me. Poor maintenance caused 2 bad spark plugs, this caused 2 damaged ignition coils and finally the cat was destroyed. It's costing me a ton of money since I imported a GMC Terrain to Ecuador and there are no parts for replacement available in here.

[@downside1237]

I have a P0420 on my 2011 Honda CRV I changed both oxygen sensors and it went away for about a week and then it came back so I'm supposing I may have a leak somewhere. I checked under the car I didn't find any holes anywhere but I did notice that the top or pre cat catalytic converter is very red and bluish does that indicate damage? If it does do you suppose that I could be burning some fuel or oil into the catalytic converter? I don't want to replace it without being sure that I found the problem that caused the damage to the cat. what would you recommend on how to proceed?

[@87studga]

I have a 2007 Mitsubishi eclipse and my exhaust flange isn’t tight and I did the water and soap test with the vacuum and my exhaust flange was bubbles could it throw the code p0421 and p0431? Please help. I change all my o2 sensors as well

[@danielcordova6356]

My 2001 Toyota Corolla has po420 but I don't know what it is any idea

[@howtoguroo2686]

p0420 on my dodge 1500 ram says left side , so I must have a leak on left side some where . with dodge you just cycle the key 3 times and the codes come up on odometer

[@FixingWithPassion]

Yes!

[@stacybarnes1789]

I am dealing with the p0420 code on my 96 toyota camry LE . Back in July I replaced fuel pump and fuel filter thinking it cause of another issue that was caused me to break down but I ended up having to replace spark plugs and cables and the culprit was my distributor cap and rotar. No more than two months later is when the p0420 code occurred and eventually would stall out while driving. I now can't keep the vehicle running even 5 minutes before it shuts off . Was going to start with my O2 sensors .....

[@FixingWithPassion]

Take a small hammer and tap on the cat and listen to any rattling. Cat could be burnt u or get a obd2 code reader and look at the o2 sensors readings after the cats... before you fix anything.

[@stacybarnes1789]

Nathan Rohrbough I had stopped by auto zone one day when the car was acting up . They did the courtesy check that’s when I found out the P0420 error code . What has me puzzled is it not staying on when I start it.

[@KRColson]

My question would be why do you continue to buy Fords after experiencing this design flaw?

[@FixingWithPassion]

Great comment!

[@aaronm406]

Yup, my ‘05 1.8 vibe has P0420 and driving me crazy to get rid of it.

[@tomryan9616]

Fuel trims will show if you have extra air.

[@FixingWithPassion]

That's a big 10-4.... Thanks!

[@samtattareeq]

Tom Ryan u mean in obd2 scanner? How will show?

[@hidigidy]

So in the case of this code, trim should read lean?

[@alb12345672]

@Vatslav Orlov More air means add more fuel to balance it out. So the trim will be POSITIVE. When it gets close to 8-10 there is a problem somewhere.

[@EGGINFOOLS]

Long-term fuel trims. Not short-term fuel trends

[@paul-fk7de]

I have a ford focus 2015 I keep getting this problem I have changed the o2 sensor but still coming up with p0420

[@FixingWithPassion]

Cat man!

[@iamericotoo]

Heyaaaa I have the code showing on my Elantra sport and it’s beginning to reduce engine speed at high RPMs. What do you suggest I do.

[@media333]

My 99 Chevy Suburban service engine light comes on just once in a while. In the past, I cleared it to see if it would go on again. Guessing it's been a year that it's been off, (anyway, it's been a long time,) now it's on again. If I have a major problem, wouldn't the light come right back on after it's been cleared? (P0420 Catalyst System Effidiency Below Threshold Bank 1)Thanks!

[@zeuswinston5004]

another thing that causes 420 and 430 codes is a cracked pipe or a leak in exhaust to cat flange if it is near your after cat oxygen sensors. any outside air (oxygen) will cause the sensor to sense oxygen which is what o2 sensors do. In a proper exhaust system any leftover oxygen is consumed in the cat converter and after cat 02 sensor would not sense o2. but if there is a crack near sensor oxygen can be drawn in and set off 420 or 430. I have LS430 and my scan reader will inform me of the known causes for the vehicle im working on. On mine it said replace exhaust y pipe. I searched internet and found out that this car had heat shields clamped to y pipe and they caused cracks on y pipe about 3 in from o2 sensor. I replace y pipe and codes went away. So also look at exhaust for air leaks.

[@FixingWithPassion]

True.

[@kingzionmusic]

I had this code the other day 98 2Dr Tahoe I put Royal purple in 3 tanks on 10 gallons each time the first 2 tanks the gunk caused the 0420 code and random misfire and burning 🔥 rich I knew it’s was because I was cleaning it 3rd tank I hit freeway within 10-15 mile Mark on freeway check engine light 💡 went off and it ran like a dream.

[@titaniumsandwedge]

Two weeks ago I changed the sparkplugs on my Nissan Frontier at 107k miles. The truck runs smoother with more pep and better mileage. But within a day or so the ECU spat out PO420 and PO430 for both banks of cats. I cannot believe changing plugs will kill both banks of cats. In changing the plugs I did have to remove the intake manifold. I did not replace the gaskets as they are silicone and reuseable. It is more logical that an air leak is the cause of my codes because it explains how both banks of cats died at the same time. The engine idles very smoothly. No hoses are missing nor do I hear any hisses. Could it be the intake gaskets?

[@FixingWithPassion]

Sounds a little of both...

[@phalanx66Satan]

plugs properly torqued ? some engines need oem 02 sensors because of some reference voltage requirement.

[@Miguelspl150]

He removed the intake.. chances are you have intake vacuum leak

[@joedso9710]

Dnt listen to these morons. What year is your frontier. At times fuel trim levels need to be reset. I dnt believe your cats will be cause by changing your plugs. If you had no check engine code before the work then double check if you might have disconnected a vacuum line. It happens.

[@gofishinginternational1865]

if you have vacuum leak, you also would have your fuel trims offset on idling

[@FixingWithPassion]

Yea the SR12 had one yesterday. You could hear it!

[@tom.dinger1823]

Listen everyone….. before anyone freaks out about the PO420 code, always check your O2 sensors, if your O2 sensors are bad it will trick the system of your car to make it think that it’s your Catalytic converter going bad. I had a PO420 code on my 2007 Chevy Malibu and i just replaced the sensors and boom CODE GONE!

[@FixingWithPassion]

Nice!!

[@Celbrise]

i got a p0420 but the vacuum leak sounds like it is coming from the catalytic converter itself. when car is in idle it sounds like there is some sort of air leak, when i gas on it the sound is louder then before.

[@markmarkin8478]

I subscribed, awesome video! Thanks

[@BAJARACER43X]

Interesting video, Im a 35 yr auto tech and a drivability specialist, air leaks cause a P0171 or a 174 , system lean, never seen a vacuum leak cause a 420. These items are easily tested with the proper scanner not a Harbor Freight code reader

[@MustangGuy1996]

My 2011 mustang 3.7 has p0420 was causing power loss and misfire but only when DECELERATING. When accelerating only slight power loss, no misfire. I replaced the bank 1 o2 sensor and catalytic converter (when i removed the old cat it was full of broken pieces inside.) the code hasn’t come back yet but the symptoms are still the same with the replacement making seemingly no difference. Just did my plugs 6k miles ago too..do you think it’s reasonable to conclude if the cat was blown on one side that the other side is likely the same?

[@isaalb33]

I got the 2010 gmc Acadia and I get P0420 and P0430 and I paid $1,300. to replace all catalytic converter and I still got the code back on. I don't good mechanics around I'm loss

[@Dangbo3030]

Get a spray can of starting fluid and with the vehicle running, spray around the intake hose's. Keep a fire extinguisher handy for safety. Just saying. If the vehicle revs up when/where you spray. You have located the culprit. Bad hose, cracked intake. Did the mechanic change the upstream O2 sensor?

[@peaceWorker77]

@@Dangbo3030 not only the code P0420 I get liquid black petroleum in the exhaust pipes after I cleaned i get it back couples hours after. I've been servicing this truck over and over and get me more problems

[@peaceWorker77]

@@Dangbo3030 and the last come to ended was the engine oil pressure switch blown probably the engine oil low pressure turn the codes. But I didn't see no smoke coming out the muffler

[@MrMusaalam]

Hi so if your plastic intake has crack wouldn’t it throw both codes. P0430 & p0420. Because I have done everything you just said in the video not to do. I would like some help. I don’t get p0420 code but p0430 code.

[@FixingWithPassion]

what is this on?

[@MrMusaalam]

2007 Toyota FJ cruiser 4wd

[@FixingWithPassion]

Gotta do a wave form on a obd2 code reader. Look at the o2 sensor after the cat. Is the waveform signal the same as the front o2 sensor? If it is then you have a bad cat.

[@oljames1687]

..those engineers who designed the plastic intakes ought to be horse whipped. Like Dana Carvey said once- "..useless piece of plastic." ...!!

[@EGGINFOOLS]

This one wasn't plastic

[@dualsportdiary1150]

Just like plastic radiator tanks... WTF CHUCK????

[@RockyRepairs]

Engineer: let’s use metal Boss: you know how expensive that is? Just use plastic! We can’t lose this contract. Well blame the cracks on improper maintenance or something like that