Catalytic Converter Efficiency Below Threshold: Code P0420 & P0430 Diagnosis and Repair

hello viewers welcome to k diagnostics duo here today we have a 2004 hyundai sonata with a 2.7 litre the complaint on this car is that the check engine light remains on while the engine is running the customer said after the check engine light came on he didn't notice any drivability concerns the vehicle seems to drive fine but the only issue is the check engine light that's remaining on while the engine is running so the first thing we're gonna do is we're gonna go inside the car and confirm the customer's complaint after confirming the customer's complaint we're going to connect the scan tool to the car to see what kind of travel codes we have in memory so we can know what directions we can go to fix this so let's go inside the car and confirm the customer's complaint all right so we're gonna confirm the customer's complaint by starting the car so let's start the engine [Music] so the car is running and as you can see the check engine light remained on so right there customer's complaint confirmed all right so right there the check engine light is on okay so we've confirmed the customer's complaint so now i'm gonna connect the scan tool to the car to see what kind of trouble codes we have in memory so i'm gonna turn off the engine i'll get the scan tool connected and bring you guys back up all right so i got the scan tool connected to the car and here are the trouble codes that we have in memory the first code is p0430 catalyst system efficiency below threshold bank two and then the second one is p0420 catalyst system efficiency below threshold bank one so these codes are pretty self-explanatory i mean the catalytic converters are no longer working properly so we have bad catalytic converters on this engine that's why the check engine light is remaining on the customer said that the vehicle is driving fine and no wonder the drip the vehicle is driving fine because catalytic converters usually don't cause the engine to run bad unless you have catalytic converters that are clogged if you have a clogged catalytic converter that can cause your engine to not even start or it can cause the car to lose power but if they're not being effective anymore your engine will still run fine but the check engine light will remain on so that is why the vehicle is running fine but the check engine light remains on and then i also have to point out that the customer told me that the engine was replaced on this car about two months ago so that is good information to know because if the previous engine had issues that could have damaged the catalytic converters because usually what i see the issues that i see that damage catalytic converters is it means firing engine an engine running rich a leaking head gasket and the list is the least can go on and on and on so catalytic converters usually don't go bad by themselves you have to figure out what caused these catalytic converters to go bad because if you just replace the catalytic converters and you don't get to the bottom of what caused the catalytic converters to go bad in the first place it's going to be a comeback just in a short time those new catalytic converters you're going to replace will go bad again so we will most likely i'm sure we're going to replace these catalytic converters but we have to do a little bit more investigating so we can know what went wrong on this engine that killed the catalytic converters basically okay so let's talk a little bit about catalytic converters well a catalytic converter is a device that is on the exhaust stream and the catalytic converter's job is to turn harmful gases that are produced by the engine into safe gases so those harmful gases are gases like carbon monoxide nox hydrocarbon and so on so the catalytic converter actually absorbs those gases and then he turns it into safe gases like like uh carbon dioxide water and so on okay so because we have these catalytic converters on vehicles nowadays for emission purposes we don't want vehicles polluting the air because if we have vehicles driving around and polluting the air that can be bad for the health of people around right so now what i need to do is i want to look at some live data so i can see how well this engine is running so i'm gonna back out of here and go to data display so we're gonna go to display current data now you might wonder why am i doing this well like i said there are a couple of things that cause catalytic converters to go bad usually catalytic converters don't go bad don't go bad by themselves unless the substrate inside the catalytic converters start to break and usually when they break they clog the catalytic converter and then you're gonna have all kind of power loss issues and stuff and i don't think that's the case here now you have to make sure that your engine is running fine it's running around stoichiometric your fuel and mixture ratio is being commanded right so it's going your engine is switching between reach and lean properly now before we look at the data before we talk about the data we're going to see you can have a bad sensor like a bad o2 sensor sending a skewed signal to the pcm the pcm is going to adjust the mixture accordingly but if it's getting the wrong information for a o2 sensor for example the mixture is going to be wrong and that can also cause the catalytic converter to go bad and the list can go on and on you can have a bad mass airflow sensor that's sending a skewed signal you can have an engine coolant temperature sensor that's standing that's sending a skewed signal you can have an open injector that's causing the engine to run reach so there's so many variables there so now with this list i don't want to look at all the data i just want to look at the data that will be relevant to me what i want to know is i want to know if the engine temperature sensor is working right i want to know if my o2 sensors are working right and i also want to know if this engine is running well in terms of fuel delivery so we're going to look at fuel trim numbers we're going to look at o2 sensor data bids engine coolant temperature sensor data period and the mass effort sensor data bid so we're gonna customize this list we're gonna deselect all so let's just grab the engine speed engine coolant temperature sensor mass airflow sensor data bid short and long term fuel trim numbers and o2 sensor data bids so that's all now we're going to list this now you want to do this test with the engine at operating temperature as you can see right now this engine is fairly cold our temperature is 84 degree fahrenheit i'm gonna start the car and then we're going to let the engine idle until it reaches operating temperature so we can do our test basically so we can look at the data and see what type of data we're getting we're going to look at these data at idle and at higher rpms you want to do this with the engine hut because catalytic converters start to work properly when the engine is hot and your o2 sensors will also start working when the engine is hot so now i'm going to start the engine so we're gonna let the engine idle right now we are at 84 degree fahrenheit like i said i'm gonna let it idle until the temperature gets up to around 180 or 190 and then i'll bring you guys back up so we can analyze the data so i will get the engine reach operating temperature and bring you guys back up all right so the engine is still running and our engine has reached the operating temperature so the engine temperature is around 188 degree fahrenheit so this is a good temperature now we can analyze the data right now i'm going to focus on the fuel trim numbers first the fuel trim numbers will tell me how the engine is running in terms of the fuel delivery fuel trim numbers can give you a good indication on whether you have good fuel pressure or you have low fuel pressure and so on because if my engine is running rich i will be able to tell with the fuel trim numbers that i'm going to see here okay if my engine is running lean and it's the same thing with a few trim numbers i'm going to get i'll be able to tell if my engine is running lean so basically what we need is we want the engine to run uh basically close to stoichiometric which is uh 14.7 parts of air and one part of fuel okay now the fewer trim numbers the rule of thumb with a few trim numbers is the total uh number is plus or minus 10 percent so we don't want a number above 10 percent okay ideally below 10 is good but above 10 total fuel trim numbers so my long-term fuel trim numbers and uh short-term fuel trim numbers together now let's look at these numbers at idle first and then we will also look at them at higher rpms so now here our long-term fuel trim numbers so long-term fuel trim numbers bank one we are reading 2.3 percent and on bank two we are reading zero point eight percent so these are good numbers now let's look at the short term fuel trim numbers we are reading minus so this on the short term numbers these numbers will fluctuate they will go between negative and positive numbers so right here and with these numbers if you see high positive numbers that means your engine is running lean okay so the computer is sending a rich command if you see negative numbers high negative numbers it means your engine is running rich so the computer is taking away fuel and as you can see right here our numbers at idle are definitely within the 10 range so this is good our engine is definitely running fine the air fuel mixture is good it's within spec it's not running too rich it's not running too lean everything looks good so now let's increase the engine rpms because i'm increasing the rpms because you can have an engine running rich at idle and then run fine at high rpms or you can have an engine that runs fine at idle and then runs bad at high rpms okay so we still want to look at these numbers as you can see here numbers on the long term uh trim did not change they're not changed actually and then look at the numbers on the short term so i like these numbers guys this is good we don't have a fuel delivery issue on this vehicle i mean we most likely don't have a fuel delivery issue on this vehicle and we will still confirm that with the o2 sensor uh signals okay now this is good let's check the mass airflow sensor we still have to check the mass airflow sensor because the mass airflow sensor measures the amount of air that enters the engine if the mass effluent sensor is sending the wrong signal to the engine control module your engine is not going to run well now we want to look at this number at idle and also at high rpms so mass airflow sensor grams per second this is good some people say the rule of thumb is your mass afro sensor number should be close to your engine size this is a 2.7 liter so we should have around 2.7 here but that's not accurate it depends on the car it depends on the brand the number i see here this 2.19 i mean 3.19 grams per second is pretty good so now let's rev it up to around 3 000 rpms and see so right there 5000 rpms [Music] so our mass airflow sensor went up to 120 29 i think let's see so here's the max the max on our master flow sensor was 129 so that's good i feel okay with this and this kind of uh this is starting to look like this engine is fine i believe what damaged the catalytic converters is uh the previous engine so now that we have analyzed the uh mass airflow sensor the fuel trim numbers and our engine temperature sensor data pit here is also working well it's reporting the right temperature which is good so now we're going to focus on the o2 sensors these will be the last uh sensors that i'm going to test the last pids that i'm going to analyze and then we can make the final call about this catalytic converters this is a very important step guys you want to do this because you just don't want to replace the catalytic converter without knowing what went wrong because if you just do that i'm sure those catalytic converters will not last the car will be back to your shop so now let's graph i like to graph the uh o2 sensor data bids so we're gonna graph these two we're gonna graph all of them all right so as you can see here here it says auto sensor voltage bank one sensor one and here it says auto sensor bank one no bank two sensor one so these are the o2 sensors before the catalytic converter and over here bank two sensor two and down here is bank one sensor two so these two are the sensors after the catalytic converter so basically the rule of thumb is you want your catalytic converters uh to work fine okay to not so that your car doesn't pollute the air okay so that those harmful gases can be turned into uh safe ones right now the o2 sensors here the one before the catalytic converters are the ones that have to switch so the signal we're getting here that's going between you know reach because the number you see up here so here is the reach signal and then down here is the lean signal a good engine actually fluctuates between reach and lean reach and lean so we need to see numbers going up and down here but as you can see i mean this is probably because i was revving it so this is a rich signal here and this is also a rich signal here but these two these o2 sensors are just stuck lean okay and we saw our fuel trim numbers the fuel trim numbers looked good so i've also seen bad o2 sensors trigger this po420 you might think your catalytic converters are bad while the issue is just the o2 sensor that's why this step we're about to do is very critical because you can have a o2 sensor that's sending a skewed signal to the pcm the pcm is going to think that the catalytic converter is the problem but the problem is not the catalytic converter it's the sensor itself that's why we have to look at the data and analyze the data okay so on a car with good catalytic converters the signal from the sensor after the catalytic converter will be basically constant you see right over here this is the sensor on bank two the sensor after the catalytic converter so bank one sensor two on a good catalytic converter we should see a line like a steady line going across the screen here across the graph but on the o2 sensor especially the o2 sensor after the catalytic converter it should have a steady line across and then the o2 sensor before the catalytic converter so this one over here bank two sensor one so the sensor one is the sensor before the catalytic converter so this sensor is the sensor that reports to the computer about the fuel mixture okay this should go between so you should have these highs and lows here so up here is a rich mixture and then down here is a lean mixture because this is just this car has conversion of o2 sensors and these o2 sensors are narrow band or two sensors right so so this is normal so seeing this kind of data on the sensor before the catalytic converter this is normal it's supposed to go between reach and lane reach and lane and switch this is good and same thing with this one on bank one so what we're seeing on bank one here is normal but on the sensors after the catalytic converters so bank one and bank two we should see a steady line on both of them okay this should just drop momentarily but not like this because as you can see the sensors after the catalytic converters are mirroring the sensors before the catalytic converters which is a symptom of a defective catalytic converter now we have to test these sensors we have to know if these sensors are really responding to the oxygen content in the exhaust stream how do you do that well you can do it a couple ways you can drive the engine rich by either inducing propane in the intake or you can just give it gas for a little bit and then watch for a rich signal a rich signal will be a higher reading here a higher a reading of around seven or eight millivolts because these o2 sensors are reporting in voltage so this is 800 800 millivolts so this is normal okay but this over here is definitely not normal now i want to know if these sensors are working i'm going to do that by like i said either inducing propane in the intake or pulling out an intake line to drive the engine lean a little bit to cause the engine run lean and as the engine runs lean the o2 sensors will react to the excessive oxygen that's going to flow in the exhaust stream you can do that by going under the hood and pulling out a line on the intake manifold to let excess air or extra air to flow inside the intake now i'm going to show you a pretty cool trick you can do just here from the driver's seat while you are still analyzing your data what you need to do is this works with engines with brake boosters okay i mean cars with brake boosters if you have a vacuum line that goes from the intake manifold to the brake booster you can do this test on the brake booster you have vacuum on one side and i mean atmospheric pressure on the other on the other side so now what i need to do is i'm going to create a a a vacuum lick basically so i'm going to create a vacuum lick which will drive these o2 sensors lean if the o2 sensors are working properly all these o2 sensors will go lean i'm going to do that by pumping on the bricks so as i'm doing that i'm allowing excess air to enter the intake manifold which will drive this o2 sensors lean and once i stop we will see the o2 sensors go up to the to the reach signal because then the computer is going to see a lean mixture first and then it's going to try to correct that by sending a rich signal okay so now i'm gonna pump the brakes so just like here i'm pumping the brakes right now pumping the brakes so watch this these o2 sensors if the o2 sensors are working fine they will go lean and this is what's happening on all of them do you see this so me being able to drive these o2 sensors lean this tells me that our o2 sensors are working fine so we don't have bad o2 sensors if we had bad o2 sensors the o2 sensors were gonna just be stuck going back and forth so we don't have o2 sensors that are stuck the o2 sensors are definitely responding to the mixture i mean to the oxygen contents that they're seeing on uh the exhaust stream so right here i'm driving the o2 sensors lean so now i'm gonna let off and as i'm letting off right now you will see now they will clamp up all of them so now they are the computer is actually compensating trying to compensate for this excess air that we in we introduced in the intake and you see this rich mix i mean this rich signal over here so this is cool guys this is a cool test you can do just from the driver's seat you can also go under the hood and unplug a vacuum hose that's okay but this tells me that our o2 sensors are fine okay we don't have all two sensors issues the issue is just the catalytic converter so at this point i feel comfortable replacing these catalytic converters i'm just going to replace the catalytic converters i'm going to reuse these o2 sensors and we will be fine let me drive them lean again and you'll see so one more time i'm pumping the brakes and as you can see right here i drove the o2 sensors lean and then they're gonna pack back up so right here lean so we went from lean to reach on all of them so our o2 sensors are definitely responding to the oxygen content in the exhaust stream okay so now basically i'm gonna turn off the car we're gonna go under the hood then we're gonna start tearing things down so we can replace these catalytic converters now there's another quick test i want to show you if you don't have a scan tool or if you don't really know how to read these data pids this is not really hard to do but if you don't feel comfortable reading the data bids i'm going to show you a quick test you can do to check your catalytic converters to test your catalytic converters but the downside about this test is that you can test the catalytic converters and know that your catalytic converters are not working but you will not be able to tell what's going on because we want to fix the cost not just the concern okay mostly catalytic converters are gone bad because of something uh that caused the catalytic converters to go bad so usually it's something that goes out and then it takes out the catalytic converter so you want to make sure you're fixing the cause not just the concern okay so the the test i'm gonna show you is gonna be we're gonna go under the car and the car will still be running we're gonna take a temperature measurement of the inlet of the catalytic converter and the outlet of the catalytic converter so the inlet of the catalytic converter should be hotter than the outlet of the catalytic converter if you have a catalytic converter that's working fine and with this with these catalytic converters on this vehicle i'm sure the inlet temperature will be the same as the outlet temperature because these catalytic converters are definitely not working because the catalytic converter works by storing oxygen inside it to break those harmful gases so as it stores oxygen the outside or the temperature on the outlet of the catalytic converter tends to be cooler than the temperature on the inlet of the catalytic converter so let's go under the hood i already feel comfortable replacing these catalytic converters we're just going to replace the catalytic converters we're not going to replace anything else i feel comfortable just doing that sometimes o2 sense removing all two sensors from the old catalytic converters can be tough if they're stuck there if i can't get them replaced then i mean if i can't get them removed then i'm gonna have to replace the o2 sensors but if they if they come out easily if they don't strip or anything i would just reuse the o2 sensors now we're going to leave the engine running let's go under the hood and i'll show you that quick test you can do with a thermometer to test your catalytic converter so let's go under the car all right so we are under the car the engine is still running and there is the catalytic converter right there so this is how you can test your catalytic converter with the thermometer so we're going to take a temperature measurement of the inlet of the catalytic converter so if you can see that o2 sensor right there so that's the inlet of the catalytic converter so i'm just going to take the temperature measurement there as you can see we're reading around 390 on the inlet of the catalytic converter so now i'm going to take a temperature measurement of the outlet of the catalytic converter and right there we're reading 334 so basically very close to the inlet temperature of the catalytic converter so this is the bad catalytic converter because the outlet temperature should be a lot cooler than the inlet temperature this is one test you can do with a thermometer but the downside about this is that you can't tell what went wrong or what caused the catalytic converter to go bad because you have to make sure that your sensors are working right the input and output from the computer is within spec before you replace your catalytic converters because otherwise your catalytic converters won't last they will get damaged again if the problem that made them fail in the first place is still there all right so now i'm gonna lower the car we're gonna let the car cool down and then we will start taking this catalytic converters out so i'll lower the car let it cool down and then i'll bring you guys back up all right guys so i did let the vehicle sit for about an hour the engine is cooled down now so we can go ahead and replace the catalytic converters so we're going to start by disconnecting the battery we're going to disconnect one of the terminals of the battery ideally the negative terminal and then we're going to remove the radiator i do have a video on how to remove the radiator on this 2004 hyundai sonata so if you want to know exactly how to replace the radiator on this vehicle you can watch that video so removing the radiator is pretty straightforward we're gonna remove this radiator mount this one over here this is a 12 millimeter bolt we're gonna remove this one and there's another one over here and then we're gonna disconnect this upper radiator hose and there's another one on the bottom and then we will disconnect these electrical connectors for the cooling fans there's one over here and there's this one and then we have transmission cooler lines on the bottom once we disconnect all of that the radiator is gonna come out the front catalytic converter is pretty easy the one on the front bank because once we take the uh radiator out we're gonna get access to this shield here that says hut so we're gonna remove this shield it's a little uh piece of metal that covers the uh catalytic converter so once we remove this uh heat shield we will get access to the catalytic converter so at that point we're just gonna remove the bolts these catalytic converters are combined with the exhaust main fold so we're going to remove the bolts that hold the manifold to the cylinder head and once we disconnect all the bolts and the other two bolts on the bottom of the catalytic converter we should be able to remove it the front one is pretty straightforward and easy to do the one that's a little bit tough is the one in the back so the back catalytic converter will require removing the intake manifold we have to remove the intake manifold so we can get access to the back catalytic converter so to do that we have to remove this engine cover four 10 millimeter bolts so one two three four and then these 12 millimeter bolts that hold the upper intake manifold to the bottom intake manifold so it has i believe six bolts so we're gonna remove this bolt and then we will be able to remove the uh intake manifold i mean we also have to disconnect these hoses these vacuum hoses and coolant hoses we're gonna remove this air cleaner tube so this air cleaner tube is gonna come out we're gonna so we we're gonna disconnect the accelerator cable and the cruise control cable so this is pretty straightforward guys basically you just undo all these bolts you disconnect the vacuum hoses and then you undo the uh air cleaner tube disconnect the cables and then we will have access to the back catalytic converter so i'll sit you guys over here so we can start doing [Music] that [Music] [Music] all right so i did remove the intake manifold so now we can get access to the back exhaust manifold and as you can see this is the back exhaust manifold and the catalytic converter is part of the exhaust manifold so now we're going to remove this heat shield and then we can get access to the bolt of the exhaust manifold actually before we do that before we remove these two exhaust manifolds what i want to do is i want to raise up the car and remove the lower radiator hose so i'm going to disconnect the lower radiator hose from the bottom we're also going to disconnect the transmission cooler lines we're also going to disconnect the y pipe of the exhaust system so there's a pipe that connects the front catalytic converter and the back catalytic converter so that way we're going to disconnect and remove everything at the bottom and then when we come back up here we're gonna remove the radiator and we're also gonna remove these heat shields so that we can remove the catalytic converters so now let's go under the vehicle and disconnect the exhaust system all right guys so we are here under the vehicle i did disconnect the uh lower radiator hose and the transmission cooler lines so i got those disconnected and as you can see this one is disconnected too so now what i'm going to do is i'm going to disconnect this catalytic converter flange so this exhaust flange here so this bolt right over here this one and this one over here and then we also going to disconnect the one here in the back so we will undo this one and then this one so this whole exhaust this whole exhaust here is going to come down okay i don't want to remove the whole exhaust because the bolts here in the back are completely rusted through you know they're rusted out and even if i try to hit this with the torch i might break them and if i break them i'm going to have to drill and all that stuff so i don't want to go through all the hustle of breaking bolts and trying to replace them with new ones i'm just going to lower the whole exhaust okay i'm going to lower the entire exhaust so i can have enough room to actually slide the new catalytic converters out so at this point i will undo this bolt and then i'm also going to undo these two there's two nuts right over here the whole exhaust is going to come down i just want to get it low enough to slide the new catalytic converters out okay so now i'm gonna do this so i'm gonna lower the whole exhaust system and then we're gonna go back under the hood so that we can remove the radiator because the radiator has to come out so we can get this cuddly converter out we're going to remove the radiator and then we're also going to remove the heat shields that are on top of the exhaust manifold so that we can remove this catalytic converters so i will do that and then i'll bring you guys back up all right guys so i did get the exhaust pipe removed so as you can see the catalytic converters are held onto the motor by the exhaust manifold so now we have to go under the hood so we can disconnect the exhaust manifolds from the cylinder heads so we can get these catalytic converters [Music] out all right guys as you can see i removed the radiator and now we have enough room in front of the engine so we have enough room to remove the catalytic converter now this catalytic converter is combined with the exhaust manifold so now what i'm going to do is i'm going to remove this heat shield after i remove this heat shield then we will have access to the exhaust manifold bolt once we remove the exhaust manifold bolts the catalytic converter will come out and this process is the same for both sides okay so i'm going to show you how to remove it on this side and again if you're doing both of them you just have to do the same process on the other side the other side is a little bit tighter i won't be able to show you very well because i won't have enough room back here but it's basically the same thing okay so now let's come back here and remove this catalytic conveyor so i'm going to remove this heat shield first by removing these three 12 meter mirror bolts all right so now i'm going to remove this heat shield i'm just going to put it right over here put the bolts on it so here is the exhaust manifold and the catalytic converter so i'm going to disconnect the o2 sensors the o2 sensor electrical connector is right over here so this is the electrical connector of the o2 sensor so this electrical connector has a tab that i have to push so there's a tab here this tab you push it down and then you pull okay so right there so now i'm going to disconnect the other one the other o2 sensor electrical connector is right over here this thing right over here so this connector i'm gonna disconnect this and then we're gonna undo these bolts these boards right over here so these there's six of them these exhaust manifold bolts actually there are nuts uh they are 13 millimeter nuts there's three up top and then three on the bottom once i remove all these three bolts we should be able to remove the catalytic converter so i'm gonna do that and then i'll bring you guys back up so that we can get this calorie converter out all right guys i removed all the nuts for the exhaust manifold remember i said the exhaust manifolds is part of the catalytic converse so the catalytic converter comes together with exhaust manifolds so these are 12 millimeter knots i don't know if i said 13 but these are 12 millimeter knots so i'm going to remove this last one so that we can remove our catalytic all converter so we're just going to put it right over here all right so now our catalytic converter should come out so right here right here here it comes so here is our exhaust manifold and catalyst convert so here it is i left the o2 sensors on it i will remove the o2 sensors so we can install them on the new catalytic converters so i hope you can see this catalytic converter here is completely burnt let me see let me show you so look inside this catalytic converter do you see how burnt this converter is you see how burnt the substrate inside the catalytic converter are so right there guys this is a problem bad catalytic converter and if your cuddly converters are bad like this you have to make sure that you check your fuel trim numbers check your mass airflow sensor your injectors make sure your engine is running fine before you replace the catalytic converters so we check this engine the fuel trim numbers were fine everything has checked out okay so that's why i'm just replacing the catalytic converter and i was told that this engine has been replaced recently but if you have uh po420 trouble codes don't just replace the catalytic converter make sure you know the cause make sure you know what caused the catalytic converters to go bad in the first place before you replace the new ones so now i'm gonna show you the new catalytic converter on this side i'm going to show you how to install the new catalytic converter i'm just going to do this side on camera i will do the other side off camera and then after i install both catalytic converters then i'll bring you guys back up so that we can wrap up this video so we're going to install the new catalytic converters then we will double check our repair and then we'll call it a day so so i will swap these o2 sensors i'm going to take the o2 sensors out and then i will install them on the new catalytic converter so now let's take this old catalytic converter to the bench so that we can swap the sensors and then we will come back here and install the new catalytic converter so now let's go to the bench all right so here is our new catalytic converter i did put the old category converter on the vise so i'm going to remove these o2 sensors and install them on the new catalytic converter so we're going to remove the the bottom o2 sensor first i'm going to remove this one you gotta be careful removing this because these threads sometimes strip out as you remove them so you have to be careful so i'm gonna apply a little bit of anti-seize just a little bit on the threads and then i'm going to screw this new one i mean this old one onto the new catalytic converter all right so now we're going to remove the other o2 sensor we tested these o2 sensors they were all good so they tested fine so there's no point of replacing these o2 sensors and i know sometimes these o2 sensors kind of weld themselves onto the catalytic converters or the exhaust manifolds but these ones are coming out pretty easily so we're not going to replace them so i'm installing the all the o2 sensor onto the new catalytic converter so right there so we're going to get this old catalytic converter out of the device so now i'm going to install the new catalytic converter on the vise so i'm going to put it on the vise here so i can tighten the o2 sensors all right you don't want to over torque this because you just want to go nice and snug because these o2 sensors tend to fell you may want to replace them soon so you don't want to go too tight especially doing it on the vise so because when you're here i have enough room to tighten it really tight so you don't want to get it too tight because then if it's really tight it might be hard to remove i mean the next time i mean it goes bad or the make the next time you want to remove it it can be a little hard so that's good all right so we tightened the o2 sensors on the new catalytic converter so this catalytic converter is ready to be stored so right over here guys see nice and shiny and it came with new gaskets okay so here are the gaskets so now let's go to the vehicle so we can install this catalytic converter so here is our new catalytic converter and ready to be installed i did install new gaskets too so that gasket you see down there is a new gasket so now we're going to install the catalytic converter so let me see if i can do this one-handed so right there so right there so our catalytic converter is installed so now we're gonna put the nuts on so the nuts had washers on them so the washers go first all right so i tightened all the bolts for the exhaust manifold so as you can see the new catalytic converter has been installed i also reconnected the o2 sensors so i reconnected the o2 sensor electrical connectors so now i'm going to install the heat shield so this shield right over here so this is going to go on top of the exhaust manifold all right so the heat shield is installed so we have replaced the catalytic converter so now i have to do the same thing on the other side but i'm going to do that off camera so it's the same process like i said so after i replace the catalytic converter in the back and then we're going to come back up here and install the radiator after we install the radiator then we're gonna install the intake manifold and then we will reconnect the electrical connectors and the hoses for the throttle body and then we're gonna start the engine and verify our repair so basically at this point everything is just a reverse process of what we did and replacing this catalytic converter is pretty straightforward so i'm going to do the one in the back off camera and then i'll bring you guys back up while i'm doing the uh the intake manifold and the radiator and then basically at this point we're just gonna reconnect the electrical connectors we're gonna install the radiator i will also install the exhaust pipe underneath so after i get everything installed then i'll bring you guys back up so we can verify our repair [Music] all right guys we are back here under the vehicle i did install the exhaust pipe and as you can see the exhaust pipe is installed and here is the new catalytic converter so right there and here is the one in the back i hope you can see that so right there let's look at it from this angle so there is a new cuddly conver okay so now what we need to do we have to go back under the hood and install the intake after we install the intake we're going to start the engine and then we will look at our data pit we're going to look at the o2 sensor data pit and then we're going to use a thermometer to measure the temperature of the inlet of the cat and the outlet of the catalytic converter remember the inlet has to be hotter than the outlet of the catalytic converter so let's go under the hood and install the intake manifold [Music] [Music] all right so i filled up the radiator with coolant so now i'm going to reconnect the battery terminal so that we can start the engine all right so now i'm going to go inside the car and start it all right guys so as you can hear the engine is running the engine sounds good there was a little bit of a squeaking sound coming from the belt but now it disappeared so that's good so now what we're going to do is we're going to let the engine idle until it reaches operating temperature once the engine reaches operating temperature we're going to test the temperature or we're gonna check the temperature of the inlet of the catalytic converter and the outlet of the catalytic converter so the inlet of the catalytic converter should be hotter i mean around a hundred degree fahrenheit more than the outlet of the catalytic converter so the inlet should be higher than the outlet of the catalytic converter so we're going to use the thermometer to check that and after that we're going to go inside the car and connect the scan tool to the car so we can look at live data so i'll let this engine reach operating temperature and then i'll bring you guys back up all right guys so we are back here under the vehicle but now we're going to test these catalytic converters with the thermometer remember the test that we did with the bad catalytic converter we checked the temperature of the inlet of the catalytic converter versus the outlet temperature of the catalytic converter on the bad catalytic converter the inlet temperature was the same as the outlet temperature but we know that on a good catalytic converter the inlet temperature should always be hotter than the outlet temperature so here the rule of thumb is the inlet temperature should be around 100 degree fahrenheit more than the outlet temperature okay then the outlet of the catalytic converter's temperature so we have replaced this catalytic converters before we look at our scan data we're going to use the thermometer to take the temperature of the inlet of the catalytic converter and then we're going to compare it to the temperature of the outlet so now i'm gonna point my thermometer around the o2 sensor up there so i'm taking the temperature of the inlet of the catalytic converter and as you can see the temperature of the inlet i mean the inlet of the catalytic converter is around let's see yeah around 400 degree fahrenheit okay around 400 degrees fahrenheit this is the temperature of the inlet of the catalytic converter so now we're going to take the temperature of the outlet of the catalytic converter and the temperature of the outlet should be cooler than the temperature of the inlet so let's go to degree fahrenheit so the temperature of the outlet of the catalytic converter is definitely cooler as you can see we are reading you know [Music] 246 degree fahrenheit you know compared to 400 and for so 408 degree fahrenheit that we read at the inlet of the catalytic converter so there's a huge difference i mean the difference is definitely there here the rule of thumb is that the inlet should be at least a hundred degree fahrenheit hotter than the outlet so we definitely have a discrepancy of temperature you know that's over a hundred degree fahrenheit between the inlet and the outlet temperature so this is good these catalytic converters are working we have installed good catalytic converters so now let's go inside the car and look at our signals from the o2 sensor all right guys so i am inside the vehicle we're gonna do one last check before we wrap up this video so i'm gonna start the engine so as you can see the engine is running and the check engine light remained off okay so this is good this is starting to look like a good sign the check engine light is not on i didn't rest the trouble code but i did disconnect the battery when i was replacing the catalytic converter so when you disconnect the battery it wipes out the memory in the engine computer so that's why the check engine light went off by itself but if the check engine light was still on i could have just erased the trouble code because now we have new catalytic converters our issue is no longer going to be there okay remember we tested the o2 sensors the o2 sensors tested out okay the issue was just the catalytic converters so now i'm going to bring up our scan tool here so that we can look at the signal on the o2 sensors we're going to look at what type of signals we're getting from the upstream o2 sensors versus the downstream o2 sensors so here is the scan tool already got it connected so now we're gonna let's deselect all these data pins actually let's customize this what do you see guys i can already see a huge difference so these these two are the pre-cat o2 sensors okay the upstream o2 sensors as you can see here it says bank two sensor one and down here it says bank one sensor one okay these are the o2 sensors before the catalytic converter and down here are the o2 sensors after the catalytic converter you see how different these signals look okay so now just to test the o2 sensors i'm gonna drive these o2 sensors lean okay so we're showing a lean mixture here on the downstream o2 sensors so they're both reading around 400 millivolts which is not bad so now the upstream o2 sensors are mirroring each other they're switching very well they're going from reach to lean reach to lean so this is a good signal this is the type of signal you have to see on a good working engine okay the upstream o2 sensor signal should definitely be different from the one coming from the downstream o2 sensor so now i'm gonna pump on the brake pedal so we will drive these signals here lean so we will drive these o2 sensors so as you can see we have a lane mixture here so now the computer is going to compensate and send a reach signal right there and this one here should go up as also and as you can see the downstream o2 sensors just responded to this to this reach command here too okay this is i mean we already did this before but this is how you check your o2 sensors okay this is a quick test you can do to check your o2 sensors and as you can see we have a straight line here this is the straight line that i was talking about before i said when you have good catalytic converters you should have a pretty straight and steady line coming from the downstream o2 sensor the signal on the downstream o2 sensor should be a basically a straight line so right now what's what are we reading here on the downstream mode to sensor so here we are reading yeah 430 okay i mean i'm okay with this i mean this this here looks good you can see these these signals the downstream o2 sensor signal is no longer mirroring the upstream o2 sensor signal so this vehicle is fixed uh i'm gonna leave it right over here guys it's getting late here i gotta get out of here so i will leave it right over here this is how you test and replace the catalytic converter on this 2004 hyundai sonata so i'm going to turn off the engine if you have any questions criticism about this video leave them in the comment box if you like this video give me a thumbs up if you don't give me a thumb down if this is your first time here subscribe to my channel ring the bell so you can get notified every time i upload a new video thanks for watching guys see you next time

Channel: KIT'S Auto and Truck Repair

Views: 207,118

Keywords: catalytic converter removal, how to test a catalytic converter, code P0420, Catalytic converter efficiency below threshold, how to remove a catalytic converter, how to diagnose a catalytic converter, catalytic converter replacement, code P0230

Id: tEnHS0oC3bo

Length: 59min 38sec (3578 seconds)

Published: Sat Apr 03 2021