Diagnosing a catalyst efficiency code (P0420 or P0430)

2006 Ford Taurus with a 3.0 liter engine problem with this vehicle is just a check engine light no running problems let's go to the scan tool see what we got here's a list of our trouble codes po4 20 is the one we want to address today which is our bank one cat efficiency below limit we're not going to worry about the p1000 was just simply means someone was here and cleared the codes before we got here and then also our engine speed RPM limiter reached so either somebody hit the rev limiter on this with the RPM or it was actually a mile per hour issue we're not worried about that we do have to consider the p1000 code however because this means someone was here and cleared the codes and not all of the tests have been completed yet by this OVD computer so there could be other faults you wouldn't want to let this vehicle go and promise this customer that he'll be fine after addressing this PPO 420 code you know there could be other issues here that sets a check engine light so we always want to warn customers when there are monitors that are not complete for obd to really you need to cover your butt that's what it's about so we're going to do this Pio 420 trouble code and the first thing I'd like to do when I have these is go to our data and we're going to pull up our o2 sensors and we'll do a custom data display just limit our data pidz here we're going to pull up our co2 sensors we'll pull up our short term and long term fuel trim - and what we'll do first is we'll graph these oh twos these two right here on this left column are my upstreams this is bank 1 bank 2 upstream these two are behind the cat downstream for Bank to downstream for bank 1 I'm going to start this car and we're going to warm this up take a look at these cats when we get them hot so watches scan data and of course we have a doing noise here it's our power steering pump is a little noisy get some fluid in here I'm quiet this up it is low probably a leak but as this is warming up we want to watch these Oh two's the upstream and the downstream and I'm going to hold the RPM up so warm the cat's up a little bit faster warm the o2s up faster one the system up faster I'm going to zoom out a little bit on the data a little bit better idea what's going on it's going to pause that right there for one second and talk about this data that we're looking at a lot of the material that you're going to see on the field is going to give you waveforms and talk about bad cats and they'll say that you know compare your upstream and compare your downstream and if the downstream looks like the upstream you have a bad cotton and that's what that looks like right now compare it to the bank - the thing is there's variables with this you can have a good cat that looks like that when it's cold you so we don't want to make those kind of blanket statements the other thing to you'll read is downstream Oh two should be steady all the time and that's also untrue if you're at wide open throttle and you're up streams are rich so are you're down streams if you do a rapid deceleration off you're going to have a lean condition that exhaust the down streams are going to drop lean so there is going to be some reaction I don't like this already for sure and a bad cat will exhibit that that the bad cat looks that the downstream looks like the upstream on that bad cat but just have to understand there's variables there so I want to heat this up more let's get that one out of the out of the way let's heat this cat up let's let's get them nice and hot and make sure that we're getting good data here fan just turned on we don't like this one at all wait much activity on that you're the fact is though guys we've got a lot of cat codes at the downstream sensor ends up looking like that and we still have a code for it so we can't just simply rely on the the signal alone and his frequency to say that cats good or bad pause that real quick this one however we have this hot enough that this bank 1 sensor one cat is definitely faulty now there's some things we need to consider with cat codes too and that's the oxygen sensors themselves and then also exhaust li so we want to make sure we don't have any exhaust leaks which we don't in particular upstream of the cat and then also you'd have to worry about the frequency the amplitude of the Oh twos and these are looking pretty good but I want to show you another test we unfreeze this down with this role and the test I want to do is a propane enrichment test it's also known as an oxygen storage test and I'm sure there's a few ways to do this let me zoom you out here for a second and what I'm going to do is I'm going to take right behind the scan tool but take the air cleaner just loosen it and I'm going to take this propane bottle and I'm going to go right into the intake right here with propane and I'm going to keep you focused on my scan data with the exception this time with the difference this time of showing you my short term long term fuel trim mainly short term we'll just keep the short term in the in the view here and I'll do the test and then I'll describe it to you I'll pause the screen and and describe it to you so there's my short-term thank one in bank to actually let you look the long-term real quick before we go any further just you can see that this car is running pretty well we don't have any fuel train issues long terms at zero zero two two sort IRMS perfect right where it needs to be so no mixture issues with this car right now again we're just going to focus on the short term for this test I'm going to hold it at a higher rpm so I don't stole the engine out and it's going to be a little bit tough to do coming heat a third hand but give it a shot I'm gonna raise the RPM I'm going to add propane to the intake first thing this should happen is these two upstream should go and once the short-term while I'm doing it my to short term fuel trim values should go very very negative so raising the RPM first and I'll tell you what I'm adding the propane and enough ethers okay grits negative just set the propane off cause this data capture we'll talk about it and what we want to look at is right where I turn the propane off remember as I'm adding propane we're minus 25% fuel trim at this point and the reason the computer is doing that these are my two up streams right here the reason the computer is doing that is trying to compensate for that rich condition so right where I turn that propane off is about right in that area see the OP streams drop leaned at that point maybe one click over just call it right there and then we look at our down streams and we what we want to see with a good cat is this cat should be able to catch and store oxygen so we actually want to see a delay here so if I turn if I turn the propane off the reason the mixture goes very lean upstream is that - 27 percent fuel trim command is still there so we are flooding this exhaust with oxygen right here and the reason that you have a delay in a down stream is that cat is actually absorbing some of that oxygen and causing that delay that's what we want to see with a good cat is a delay in that response notice the response time of the bank 1 sensor 1 it's almost the same as the upstream I'll zoom in on this a little bit more to give you a little bit better perspective and I'm actually maybe off a little bit on that that cursor kind of tough to get it right there but you can definitely see a difference between these two now here's the issue I don't have a good time frame for you guys I have some stuff in my book where I've done some experimentation with this I have one capture of roughly two to four seconds of delay top you I've seen good cats delay eight to ten seconds you now the problem with the scan tool is these are frames unlike a scope that does voltage over time a scan tool reports voltage over frame and my issue is I don't know how long five frames of data is so what we have here is from 1995 or 96 to roughly 2000 we have about five frames of data in delay time for this bank to cap and you know we have maybe two frames of data for this one or maybe even one if we kind of we could call it two so it's a test you can do you can see the difference between the two cats this one definitely needs to be replaced this Bank one cat but it would be nice to get some numbers here and I think what I'll do to just kind of further this is I would like to get a time frame for you guys and I'm going to hook the scope up to these for now and then we can do voltage over time do the same check and then I can give you a time frame but truthfully yeah you know what I can't even make that statement I was going to save it it's potential here that this cat is also faulty you especially when you're looking at it from a zoomed-out level there is not much delay time there and uh you know this is kind of showing you the value of this test too is you can have converters that are on the on the verge of failing or you know truthfully we have that Pio 1000 code maybe we had a po4 30 code - which is our bank to code and just hasn't showed back up yet there's a real good possibility that the recommendation for this car is going to be to do both casts so let's do the oxygen storage test again using the scope and see the result of that alright little discrepancy here guys one of the reasons we need to be careful about model years and where we're getting our information from this car is from a body saw this has a label on the front says it's a 2006 but the fin tag the 10th VIN number is a 7 so this is actually a 2007 and I had it entered right on the skin tool I miss quoted this video at the beginning this is a 2007 go by the VIN tag behind the windshield when in doubt for this next segment what I want to show you guys is the scope tests of this oxygen storage on these cats and what we've done to connect to all four oxygen sensors we've connected to the engine computer instead of crawling underneath the car and locating the downstream Oh - sensor connectors and the upstream connectors - we went to the engine computer and this was by no means easy to do we actually had to unbolt the computer connector and pull it out find the pin numbers and wire colors and it was not fun but we got all 402s connected now and let me get you a shot on the varus this is a frozen picture of the same test so we ran it at a couple thousand rpm for a few minutes got the cats nice and hot the signals you're looking at on the screen here the yellow trace is my upstream on bank one my red trace is my downstream on bank one green trace is the upstream on bank two and the blue trace here is the downstream on bank too remember we have a cat code on bank one only no code on bank two and really looking at just the upstream and downstream o two signals as the scan data showed us this is really enough info here to condemn the cat we ran it for a long time we should never see a hot cat with the same frequency and amplitude as an upstream so the downstream sensor the cat monitoring sensor we don't want to see the same frequency and amplitude as the upstream definitely a bad cat for these two so if you would just look at this area in here I want to talk about this for a second because I see a lot of material out there that is kind of true but I don't know I just don't like blanket statements so what we'll see in material out there is they'll talk about this these two and say okay we have a bad cat on bank one and I would agree and that they'll look at these two and say we have a good cat on bank two this one is the one that we have to worry about you can have a cat that has a flatline signal at times and look like a good cat but fail the OBD test for the cat so the on-board computer fails it for efficiency so maybe this test can help you with identifying those that look good as far as amplitude and frequency but maybe they don't look good for an oxygen storage test and in this area here is where I'm adding fuel you see all the o2 s went rich at that moment in time the short term fuel trim command takes all the fuel away and so I keep it there for a while and the reason I add that propane for a period of time is I want to give that sort term value a chance to take away a lot of fuel not just a little bit so I let it go for a while and then I shut the propane off here and what I can do is zoom in on this area now where everything drops lean right there that is where I turned the propane off you can see that the bank one is pretty much identical in time as far as oxygen storage goes and the bank two actually shows a delay so again upstream sensors here I turn the fuel off the reason it drops really lean really fast is the computer still commanding fuel to be negative taking fuel away so that's why we have flatline lean condition here so we're pumping oxygen into the exhaust and then what we look at is how long does it take for the cat to respond to that and you see the delay in time here so let's get a time measurement on this and this isn't exact as far as where I'm placing these cursors but we'll get an idea of like kind of right where it drops you know this doesn't have to be exact because what I'm finding is it should be I don't know I have some pictures of good ones from two to four second delay I have some brand new cat pictures this is actually in section five in my book at the very end if you refer to the last couple pages I'm showing some oxygen storage tests I have one capsule that shows two to four seconds I have another capture that shows six to ten second delay and and that was on brand new cats and this one get a number for you guys Oh point six four between my cursors so my my Delta time between my two cursors here here and here between one and two and make sure I'm looking at this right yeah my time difference between cursors 1 & 2 is just over a half a second long and I have to be honest with you guys I don't think it's enough I think what we have is a is a bank to cap that's ready to flag a code as well and I think for this customer I'm going to recommend both cats definitely going to say he needs to bank one cat and I'm going to warn him about the bank to cat at the very least so I think it's a valuable test to I identify maybe even a cat that might look good further into it like I said come back out on this picture and look in this area you might say hey that's a good cat but I don't like the oxygen storage of that cat now one last comment for you guys is I don't have enough known goods to give you a set timeframe on this I have a few captures I'm going to do a lot more I think this term and get some better numbers and get an average on what all these cats can handle in the time frame that time delay so I'll maybe update you guys on that later but I don't like this one at all bad cat bank one just suspect a cat that's failing on bank - ok some final thoughts on putting a cat in this car there's some things that we want to consider before just putting converters in cars one I mentioned before make sure we don't have any exhaust leaks upstream number two is you want to make sure the engines running well look at your fuel trim numbers make sure your fuel trim numbers are normal make sure that there's no misfires or anything like that make sure the car has been maintained and the truth is a lot of you guys are seeing the same thing I am which is we get these cars in and the damage may have been done thousands of miles ago and it just finally has showed itself in the form of a cat code but we get these cars in that have absolutely zero running problems and we have these converter codes and and when we put converters in them or fixing them so I guess another warning to that I see a lot is when you use aftermarket aftermarket cats I'm just not seeing them meet the same standards I I can think of at least 10 GM's that have had converters put on them at two to three months later they come back with the same cat code they had before and the only fix is to put a factory cat on it I've seen it on Lexus Toyota a lot of different manufacturers I'm seeing that the only fix for these is to use a factory cat and I'm not talking about a direct bolt-on om compatible I'm talking about buying it directly from the factory is the fix and you know of course you can you know go on IAT N and and read about a lot of the cat issues and them sure there's a ton of other variables anywhere from reprograms to you know issues with oxygen sensors and things like that but I just make sure myself that the O 2's are switching that they're switching fast and I don't know if we can really show too much to that see what our switch rate here is on our upstream o2 kind of kind of frequency number throw some cursors in here I'll just place them within a one-second period we don't really like to see a 1 to 2 Hertz signal when I said when I look at oxygen sensors so we're going from high to low to high in this one second P between my two cursors is one second so I have a 1 Hertz signal on my upstream sensor here I have just over a 1 Hertz signal on my bank to upstream o2 so I don't see any issue with the o2 that would be something to consider I've heard sluggish oh twos a sluggish upstream can can be a factor too I've never seen that generally speaking what I see I don't see any oxygen sensor trouble codes I only have a cat code I don't even hesitate with it anymore pretty much needs a cat a factory cat just make sure the engines running good but there's some other text look at your frequency of Euro two's you know you want to make sure you're down streams respond to and that's as simple it's easy on this one this cats totally dead but on one like this down here that's not moving much you can flood it with fuel just by fluttering the pedal and watch the reaction of the downstream sensor make sure you're good there and so you know I am by no means an expert on the chemistry of catalytic converter construction and all the variables that come with it but I know enough to put a cat in a car when I see one and hopefully I've given you guys enough information to maybe take your knowledge a little bit further and expand on what I'm doing here and like I said I'm going to update this at a later point in time with some more oxygen storage numbers our cat on this vehicle the the oxygen storage on this right in this area right in here you can see the delay a little bit better zoomed out that this area was only about a half a second I don't think it's enough when you see p0 420 codes that would be for your bank 1 and when you see p0 or 30 codes that would be for bank 2 this is bank 2 this is bank 1 again I'm going to recommend both we definitely need Bank 1 no question about it I'm going to recommend Bank 2 and I'll get you guys some numbers later with this time delay again what I said the case studies I have in my book in section 5 I'm seeing between say 2 to 4 and the 1 capture and 6 to 10 seconds and the other capture way more time than what I'm seeing here and that's what I'm going by to recommend this cat final thought on this forward guys I forgot to mention it was the test that we did for this cat this was not for a restriction we don't want to mix up restricted exhaust cat testing with efficiency cat testing when you have an efficiency code for a cat that does not mean you have a plugged up as exhaust you can also have a plugged up exhaust which would be a melted cat and not have an efficiency code two completely separate tests you do back pressure testing for plugged exhausts the efficiency test that we just showed you is not for low power conditions and things like that we can have a cat that has perfectly good flow through it not restricting the exhaust and still be bad because it doesn't do its job anymore we can also have a cat that's completely plugged up and causing a running problem so two ways that they fail and I want to be clear on that and I know some of you are probably going to chime in here and say that why don't you do Inlet and outlet temperature tests on the converter and I have to be honest with you guys I don't like that test I think it's I just think there's too many variables to it I mean what if you have a clean running engines running perfectly is your outlet of the cat going to be hotter than the inlet that's the theory behind it the outlet should be 10% hotter it's just there's variations to that how well is that engine running how long have you been running the car did you warm it up sufficiently I don't know I don't like the temperature test but to each his own hopefully you guys like the oxygen storage test that I've shown you today it's another way another tool you can put in your toolbox when it comes to cat testing you

Channel: ScannerDanner

Views: 423,331

Keywords: Catalytic Converter (Invention), oxygen storage test, Auto Tech, scannerdanner ebook, P0430, how to, fuel trim, catalytic converter test, Oxygen (Chemical Element), P0420, 2007 Ford Taurus, what should a downstream O2 look like, DIY auto repair, auto tech training, mechanic school, Rosedale Tech Pittsburgh, scannerdanner, Paul Danner, Engine Performance Diagnostics, How to test a catalytic converter

Id: vyVnhCIMDnw

Length: 30min 24sec (1824 seconds)

Published: Thu Jun 13 2013