... Speaking of analyzing data provided - when I hear someone explain something complex in short, precise, and easy to digest terms, it proves that the person truly understands the subject. It also says that you too had a very good Instructor.
great explanation! I would also check the spark plugs on wear. I once had a p0420 and did a test on the gas analyzer. It passed the test, so i checked the O2 sensor and noticed sensor 1 (air/fuel) switching alot and also the O2 downstream. I went on and checked spark plugs and they were pretty worn. I changed the spark plugs and did a reset of adaptive values. Since then i always check the spark plugs to be sure the computer is not compensating for worn spark plugs
Thank you Sean, you are correct, its always a good ideas to use a scope or visually inspect the secondary ignition system, to prevent carbon fouled cat.
For my P0420 tests I also like to compare the reaction time of the upstream 02 against the down stream O2. I mainly work on Toyota and Subarus (which use AFR for the upstream). 90% of P0420 codes (I encounter) are related to a slow reacting upstream O2 and /or bad spark plugs
Great video Oscar! Love your explanation of examining the root cause. Seen many shops load the cannon without any further evaluation. Misfires and fluid consumption are the main killers of catalysts. Also, amazing what's capable with dongle and a phone!
Hey Matt, thank you for your kind words. Sadly to many shops and techs will just throw parts without first analyzing whats the root cause. I highly recommend the topscan, very powerful tool.
Nice job Oscar. I was just trying to explain to somebody the other day about this being a pro tool versus a non-tool. This does keep up with even the highest end scanners. You cannot beat this for the money.
thanks for this video bro!! i just rebuilt the engine on my moms suv and it also suffered from oil consumption prior to the rebuilt (we bought the suv used). now that i rebuilt the engine, i started losing a bit of power once the engine is on the road after 15-20 minutes. Nothing drastic, but definitely noticeable. I got the P0420 code, and my dumbass cleared it cause I knew i had to probably replace the cat now, but it never occurred to me that it could've been going on ever since the oil consumption. i have a scanner and am going to try out your live data test, and also look into that scanner you're using. i like how it had way more detailed diagnostics.
U did a hell of a job showing how 2 do it if anyone says it was bad they have no idea about cars truck or for that matter any thing They're just r***** thanks again !!
Cool. I had an intermittent P0420, which turned out to be an exhaust leak at the Manifold donut gasket. Worn engine mounts also added to the leak. A new gasket and mounts fixed it (use OEM for these). Downstream O2 sensor was reading lean. Car is a 2006 Matrix 4WD with 225k miles.
Great informational video. My 2005 Honda Civic has the same code and from your video I realize my CAT may be toast due to a very small head gasket leak that likely caused the CAT to overheat due to the coolant and tripping the code. 🤞that it's the O2 instead.
How does ethanol affect ECM/PCM fuel trim calculations? Does it require the same 14.7:1 ratio calculations or some other ratio? If so does the ECM/PCM sense whether the fuel is ethanol or gasoline and use a different ratio for ethanol? If the ECM/PCM assume gasoline is used and does not adjust for the use of ethanol what is the impact on air/fuel calculations and fuel trim outputs? How does this affect scanner outputs, rich, lean, etc.? Is there a YT video that addresses these questions? Bottomline: How does the ECM/PCM adjust for these two different fuel types with different optimum air/fuel ratios, or does it not, and what are the impacts on scanner readings and diagnosis? Again, is there a YT video that addresses these questions?
Oscar Gomez Master Automotive Training Enjoy your 4th of July with all your family around you Brilliant video tutorial outstanding 👍 WHIP SMART, Oscar Gomez Master Automotive Training From Nick Ayivor from London England UK 🇬🇧 ⏰️ 7:04AM Good Morning 🌧 and more 🌧
Great video a lot to remember if you don’t deal with cat codes a lot but it makes sense so I saved it mode 6 is very powerful can you do more micsig scope classes
Thanks for your time and experience…Can the PO420 code also be cleared by removing the cat and soaking it in soapy distilled water for a day then put back in for the DIYer trying to save money …?
Good stuff, I do have a question I have replaced both cat and o2 sensors, it had a multiple miss fire , and I hear while accelerating a big bang coming from the cat, also I have a small leak from the exhaust connector where they joined , but a mechanic told me that that is not the issue because is not between the o2 sensor , is this correct? Thanks
It's a good method or even using a thermal imager, you just need to test many known good cars to have an idea of what's good vs. what's bad, to then apply to your diag.
Clicked on the video hoping to get some insight on my wife's 07 Honda Accord, been getting an intermittent po420 for 5 years, the cats aren't cheap for these cars, so I'm glad I didn't break down and get one at the first sign of the po420, car runs great, haven't had any other trouble codes, just don't understand why or how this code pops on for awhile, only to go back off for awhile, if the cat is on its way out, why has it kept doing this for 5 years, I just don't get it
You're suffering from a weak cat. During the entire video I explained how to test it to know if it's the cat or an input sensor. If you follow the same steps you'll be able to determine the true cause. Curious what type of insight did you expect to see?
@@MasterAutomotiveTraining I was hoping to understand why her car has had the intermittent 420 for so many years, I guess I did get some insight, I just didn't think that a cat could remain in the weak stage of it's life for so long, thought that maybe there is a problem I hadn't heard of yet, meant no offense to your video, you obviously know what you are doing, and I always like to listen to everyone's perspective, every time her engine light comes on because of the 420, I think is it finally going to go out, but after years of this, you begin to wonder, is there something going on I'm not aware of, I reckon it's just living on the brink.
Hey I had a Tahoe with a returning P0420 code, previous techs had replaced cats twice on it, I got it and could not condem the cat, but they wanted me to put another cat on. Code returned. Later found that coolant temp was only getting up to 180F now matter how long it ran. I put in a resister to the coolant temp connector and verified computer could read 200 degrees, it was able to, tested the coolant temp sensor and found according to the temp to resistance chart. Also passed, so I recommend thermostat customer declined and left. My question is, if coolant temp doesn’t not get up to temp how can that effect just one bank and cause the p0420 back? It’s driving me nuts lol
I can't see how a coolant temp issue would cause a single bank issue. was it California emissions, possible that you were using the wrong cat? is it oem cat? I have seen new aftermarket cats set 420 code
It's called time to temperature. On my previous video of the 3 PIDs I speak about it. If the ECT takes too long to warm up the monitor won't run or run at the wrong time causing a false DTC. You can also read that same info in service info it's part of the code setting criteria. Great catch.
@@MasterAutomotiveTraining holy shit must have missed that. I sincerely hate a vehicle leaving that was not properly diagnosed. I NEED it fixed. Thank you.
@@MasterAutomotiveTraining I'm currently using HP Tuners to do the same tests, but the supported vehicles are limited. I did notice on a 2014 Silverado with a 5.3 L83 with a bad thermostat that almost all emissions tests fail to run until the target coolant temperature is reached. I am assuming that most systems are the same. Do you have an affiliate link to the scanner you are using? dragging a laptop out to diagnose is very cumbersome, and a huge pain in my ass.
You may misunderstand... trim is not "all" of the fuel, it is the small amount added/subtracted from the base fuel map. Base plus trim equals total. There are also long and short term trims, I'm just simplifying.
2005 Toyota Corolla le, brand new 02 sensor upstream and downstream, brand new catalytic converter CARB California, brand new battery, brand new spark plug,anyway, no codes and always not ready the O2 sensor i failed in the smog check. Drive cycle is like 2000 miles now.
I got a question bro.. i had this same code on my 2008 Dodge Avenger. It was time for me to get my emissions test done, so i bought a new Cat, and both oxygen sensors. I got them replaced and the code went away and i was able to pass the emissions test. About a month had passed and now the code is back. I dont know what to do at this point
Hey man, do you have a shop where you do smog diagnosis? I am local to you and i have been playing parts cannon with my 94 jeep 4.0 for 15 years. im about to throw in the towel. Id love to see if you can diagnose.
Of course man, we are Master Auto Care. 9233 Archibald Ave., Rancho Cucamonga, CA 91730. 909-493-1855, give us a call to setup an appointment and we can definitely help you get it fixed.
I have been having problems with My 2018 Hyundai Elantra Chacon SEL with a PO420 Code. I have been trying to fix the problem and clear the code so I can get it fixed so I can sell the car. The car has 225,000 plus Miles on it. When I bought the car 2 Years Ago, it had 86,580 Miles. I am the 3rd Owner on the car and I drive for Uber.
can someone who knows what this guy is talking about make a lil bullet point list on what tests to run/pull up and the respective criteria, and the reasoning behind it? Its a lil hard for me to follow cuz he only talked about what to look for but not why, sometimes
@@MasterAutomotiveTraininglike why we wanna check for the fluctuations in the charts, what does the fluctuations or lack thereof indicate in the system
Well, I started explaining the proper process at :50, I believe you wanted a video saying replace this part for this code. I'm not a parts changer and don't teach that, since that's what you want, I'm not the channel or teacher for you, best of luck with parts changing.
![OBD2 Scanner Live Data Explained: [Top 3] Data PIDs](http://i.ytimg.com/vi/9YLHaavMDVw/mqdefault.jpg)
![เปิดใจ พี่ญา คนรุม หลังทัวร์ลง หนักสุดในชีวิต!! l [Nickynachat]](http://i.ytimg.com/vi/2-OJZRtclro/mqdefault.jpg)
... Speaking of analyzing data provided - when I hear someone explain something complex in short, precise, and easy to digest terms, it proves that the person truly understands the subject.
It also says that you too had a very good Instructor.
great explanation! I would also check the spark plugs on wear. I once had a p0420 and did a test on the gas analyzer. It passed the test, so i checked the O2 sensor and noticed sensor 1 (air/fuel) switching alot and also the O2 downstream. I went on and checked spark plugs and they were pretty worn. I changed the spark plugs and did a reset of adaptive values. Since then i always check the spark plugs to be sure the computer is not compensating for worn spark plugs
Thank you Sean, you are correct, its always a good ideas to use a scope or visually inspect the secondary ignition system, to prevent carbon fouled cat.
For my P0420 tests I also like to compare the reaction time of the upstream 02 against the down stream O2. I mainly work on Toyota and Subarus (which use AFR for the upstream).
90% of P0420 codes (I encounter) are related to a slow reacting upstream O2 and /or bad spark plugs
Best video I have seen using a scanner to diagnose a P0420.
This guy gives awesome information. A little too fast for us limited do it selfers, but definitely worth rewinding over again.
Great video Oscar! Love your explanation of examining the root cause. Seen many shops load the cannon without any further evaluation. Misfires and fluid consumption are the main killers of catalysts. Also, amazing what's capable with dongle and a phone!
Hey Matt, thank you for your kind words. Sadly to many shops and techs will just throw parts without first analyzing whats the root cause. I highly recommend the topscan, very powerful tool.
Great job! I’m going to steal this explanation for my channel
Go for it! Just pass on some recognition 😉
Nice job Oscar. I was just trying to explain to somebody the other day about this being a pro tool versus a non-tool. This does keep up with even the highest end scanners. You cannot beat this for the money.
Thank you my friend. I always say gear doesn't buy skill lol. Im very impressed with the topscan and I tell everyone its my techs go to tool.
This taught me a new way of testing cats. Thanks for taking your time for sharing your knowledge with us!
Glad it was helpful! Thanks for watching.
thanks for this video bro!! i just rebuilt the engine on my moms suv and it also suffered from oil consumption prior to the rebuilt (we bought the suv used). now that i rebuilt the engine, i started losing a bit of power once the engine is on the road after 15-20 minutes. Nothing drastic, but definitely noticeable. I got the P0420 code, and my dumbass cleared it cause I knew i had to probably replace the cat now, but it never occurred to me that it could've been going on ever since the oil consumption. i have a scanner and am going to try out your live data test, and also look into that scanner you're using. i like how it had way more detailed diagnostics.
Best explanation that I've seen for analyzing the PID data, thanks!
I think I got it …it’s little be advanced for me ,,,I gonna study it more ..Thanks again appreciate
You got this! Look it over once again, and test it out!
U did a hell of a job showing how 2 do it if anyone says it was bad they have no idea about cars truck or for that matter any thing They're just r***** thanks again !!
Thank you for watching my brother and dope comment!
Cool. I had an intermittent P0420, which turned out to be an exhaust leak at the Manifold donut gasket. Worn engine mounts also added to the leak. A new gasket and mounts fixed it (use OEM for these). Downstream O2 sensor was reading lean. Car is a 2006 Matrix 4WD with 225k miles.
Very nice! That's a common issue, great catch. Thanks for sharing this helps other Incase they run into a similar issue.
Cool video! Usually a leak, sensor, gasket or a bad cat cause this issue.
Great informational video. My 2005 Honda Civic has the same code and from your video I realize my CAT may be toast due to a very small head gasket leak that likely caused the CAT to overheat due to the coolant and tripping the code. 🤞that it's the O2 instead.
Great video, thank you!
bien facilitoooo when you understand well hopefully soon i get that.... great video
How does ethanol affect ECM/PCM fuel trim calculations? Does it require the same 14.7:1 ratio calculations or some other ratio? If so does the ECM/PCM sense whether the fuel is ethanol or gasoline and use a different ratio for ethanol? If the ECM/PCM assume gasoline is used and does not adjust for the use of ethanol what is the impact on air/fuel calculations and fuel trim outputs? How does this affect scanner outputs, rich, lean, etc.? Is there a YT video that addresses these questions? Bottomline: How does the ECM/PCM adjust for these two different fuel types with different optimum air/fuel ratios, or does it not, and what are the impacts on scanner readings and diagnosis? Again, is there a YT video that addresses these questions?
Good explanation. Keep the videos coming
Thank you for watching more to come!
Yes more technical videos!
Oscar Gomez Master Automotive Training
Enjoy your 4th of July with all your family around you
Brilliant video tutorial outstanding
👍
WHIP SMART, Oscar Gomez Master Automotive Training
From Nick Ayivor from London England UK 🇬🇧 ⏰️ 7:04AM Good Morning 🌧 and more 🌧
Thank you my friend! Your support is amazing!
Hello! Love all of your lessons and have helped me with ase tests. Was wondering if you had an ase 2 automatic transmission course…
Great job man
Thank you for watching.
Great video a lot to remember if you don’t deal with cat codes a lot but it makes sense so I saved it mode 6 is very powerful can you do more micsig scope classes
Great vid man. Just found the channel
Welcome aboard! Thank you for watching.
good job man , thanks
Glad it helped, thanks for watching.
Thanks for your time and experience…Can the PO420 code also be cleared by removing the cat and soaking it in soapy distilled water for a day then put back in for the DIYer trying to save money …?
Good stuff, I do have a question I have replaced both cat and o2 sensors, it had a multiple miss fire , and I hear while accelerating a big bang coming from the cat, also I have a small leak from the exhaust connector where they joined , but a mechanic told me that that is not the issue because is not between the o2 sensor , is this correct? Thanks
Hi do you believe in using a digital laser temp gauge the one you point or a infrared camera with temperature readings
It's a good method or even using a thermal imager, you just need to test many known good cars to have an idea of what's good vs. what's bad, to then apply to your diag.
good job Oscar!
Thank you for watching!
Clicked on the video hoping to get some insight on my wife's 07 Honda Accord, been getting an intermittent po420 for 5 years, the cats aren't cheap for these cars, so I'm glad I didn't break down and get one at the first sign of the po420, car runs great, haven't had any other trouble codes, just don't understand why or how this code pops on for awhile, only to go back off for awhile, if the cat is on its way out, why has it kept doing this for 5 years, I just don't get it
You're suffering from a weak cat. During the entire video I explained how to test it to know if it's the cat or an input sensor. If you follow the same steps you'll be able to determine the true cause. Curious what type of insight did you expect to see?
@@MasterAutomotiveTraining I was hoping to understand why her car has had the intermittent 420 for so many years, I guess I did get some insight, I just didn't think that a cat could remain in the weak stage of it's life for so long, thought that maybe there is a problem I hadn't heard of yet, meant no offense to your video, you obviously know what you are doing, and I always like to listen to everyone's perspective, every time her engine light comes on because of the 420, I think is it finally going to go out, but after years of this, you begin to wonder, is there something going on I'm not aware of, I reckon it's just living on the brink.
Have you had a new car block you out of the system ? You can pull codes but no live data ,no bidirectional just Codes.
It must have asecure gateway man
Not yet, you'll need to get your scan tool registered with Autoauth and also get your VSP for the new changes.
Right on ! Nice!
Hey I had a Tahoe with a returning P0420 code, previous techs had replaced cats twice on it, I got it and could not condem the cat, but they wanted me to put another cat on. Code returned. Later found that coolant temp was only getting up to 180F now matter how long it ran. I put in a resister to the coolant temp connector and verified computer could read 200 degrees, it was able to, tested the coolant temp sensor and found according to the temp to resistance chart. Also passed, so I recommend thermostat customer declined and left. My question is, if coolant temp doesn’t not get up to temp how can that effect just one bank and cause the p0420 back? It’s driving me nuts lol
I can't see how a coolant temp issue would cause a single bank issue. was it California emissions, possible that you were using the wrong cat? is it oem cat? I have seen new aftermarket cats set 420 code
@@JOHNPHUFNAGEL yes I checked all of that,it was an aftermarket cat, but the last two were OEM.
It's called time to temperature. On my previous video of the 3 PIDs I speak about it. If the ECT takes too long to warm up the monitor won't run or run at the wrong time causing a false DTC. You can also read that same info in service info it's part of the code setting criteria. Great catch.
@@MasterAutomotiveTraining holy shit must have missed that. I sincerely hate a vehicle leaving that was not properly diagnosed. I NEED it fixed. Thank you.
@@MasterAutomotiveTraining I'm currently using HP Tuners to do the same tests, but the supported vehicles are limited. I did notice on a 2014 Silverado with a 5.3 L83 with a bad thermostat that almost all emissions tests fail to run until the target coolant temperature is reached. I am assuming that most systems are the same. Do you have an affiliate link to the scanner you are using? dragging a laptop out to diagnose is very cumbersome, and a huge pain in my ass.
This was good. Thanks.
Glad you enjoyed it!
Thank you for covering MODE 6. 😤
Very good info my friend!
Glad it was helpful! Thank you for watching.
@MasterAutomotiveTraining
Np and i subscribed to your channel. 😎
Great content as usual
Much appreciated,thank you for watching.
Wouldn't negative fuel trims indicate that the car is decelerating, since the pcm is removing fuel instead of adding it?
On decel it goes into OL-Drive and trims aren't being monitored by PCM.
You may misunderstand... trim is not "all" of the fuel, it is the small amount added/subtracted from the base fuel map. Base plus trim equals total. There are also long and short term trims, I'm just simplifying.
2005 Toyota Corolla le, brand new 02 sensor upstream and downstream, brand new catalytic converter CARB California, brand new battery, brand new spark plug,anyway, no codes and always not ready the O2 sensor i failed in the smog check. Drive cycle is like 2000 miles now.
I got a question bro.. i had this same code on my 2008 Dodge Avenger. It was time for me to get my emissions test done, so i bought a new Cat, and both oxygen sensors. I got them replaced and the code went away and i was able to pass the emissions test. About a month had passed and now the code is back. I dont know what to do at this point
Leak test the exhaust
@@LordOuzinthanks. I’ll give it a try
Hi Oscar jw what’s the upstream and downstream 02 sensor called in tapdon phoenix read data? Thank you
You can run on some toyotas the cat monitor , zero mph
At idle?
Hey man, do you have a shop where you do smog diagnosis? I am local to you and i have been playing parts cannon with my 94 jeep 4.0 for 15 years. im about to throw in the towel. Id love to see if you can diagnose.
Of course man, we are Master Auto Care. 9233 Archibald Ave., Rancho Cucamonga, CA 91730. 909-493-1855, give us a call to setup an appointment and we can definitely help you get it fixed.
Data data data 😊
Coming up! 😃
I have been having problems with My 2018 Hyundai Elantra Chacon SEL with a PO420 Code.
I have been trying to fix the problem and clear the code so I can get it fixed so I can sell the car.
The car has 225,000 plus Miles on it. When I bought the car 2 Years Ago, it had 86,580 Miles.
I am the 3rd Owner on the car and I drive for Uber.
can someone who knows what this guy is talking about make a lil bullet point list on what tests to run/pull up and the respective criteria, and the reasoning behind it? Its a lil hard for me to follow cuz he only talked about what to look for but not why, sometimes
I'd like to know more, what do you mean by why?
@@MasterAutomotiveTraininglike why we wanna check for the fluctuations in the charts, what does the fluctuations or lack thereof indicate in the system
😅😅more like gone grab my taco n let's eat fstzzzzzzz
Comparing it with Phoenix Max is not correct
All the knowledge in this video yet, you focus on that comparison, well ok. Good to know.
@@MasterAutomotiveTraining😂😂
Bla bla bla for five minutes, and you haven't started explaining the code yet.
Well, I started explaining the proper process at :50, I believe you wanted a video saying replace this part for this code. I'm not a parts changer and don't teach that, since that's what you want, I'm not the channel or teacher for you, best of luck with parts changing.