Expert Techniques in Advanced Vehicle Diagnostics: O.B.D. II Secrets Unlocked

[Music] hi I'm electron John from a and we're going to continue on with part three of our diagnostic series here today this part is all going to be centered around OBD2 real quick a big refresher with OBD2 we'll go through some slides and then we're going to go through some OBD2 stuff on a scan tool here so with that being said for those of you that maybe are younger techs that's probably the only type of computer controls your custom to seeing when they come into your auto repair shops but the question is was there an OBD1 and the answer is definitely there was an OBD1 it was kind of like the wild west every manufacturer could do whatever they wanted which made it more difficult for us older text to have to have you know scan tools that were totally updated with all the different manufacturer software um different diagnostic connectors some of them were inside the car some were outside underneath the hood so what OBD 2 was is it came out with a standardized OBD2 connector it had to be in a standardized location and it kind of leveled the playing field for us technicians so we could had the ability to diagnose any type of car and even your cheaper scan tools that you could get for you know the $100 range is more than capable of diagnosing OBD2 sometimes people refer to that as generic OBD2 sometimes I refer to it as Global OBD2 it's pretty much much the exact same thing so no matter how people refer to it what we're about to share with you here today is going to help you understand how valuable of a diagnostic tool this is I tell people all the time that I diagnose 85% of my drivability related problems just using OBD2 nothing else and there's advantages as to why I go to OBD2 and it has the standardized information for every type of car which which is a huge asset when it comes to diagnosing different types of vehicles so why would I ever want to use OBD2 well I want to use OBD2 because it's the same on every vehicle doesn't matter what the name plate is on the fender it's also does not display substituted values so what does that mean if I were working on say a Chrysler product or some of the OEM types of cars out there and let's say I did something like unplug a cool and temperature sensor or I had a hard fault you know that created a trouble code on its own and I go look at the data stream it would give me a known good value in the data stream that could be confusing it'd be a code associated with it but it might not make sense to me so that's one huge reason why going to OBD2 is so beneficial for a diagnostic Tech because you're looking at live data that's not a substituted value that a manufacturer puts in it will work even if you don't have the latest update on your scan tool so you have a scan tool assuming the scan tool doesn't brick when it gets out of subscription but the altel brands don't brick on you which is a great thing um I can just go ahead and plug right into the OBD2 connector and let's say it happens to be a 2023 model year car but maybe I didn't update my software since 2018 not a big deal I'm going to the global side of OBD2 the scan tool is still going to work for us it also will show you strategies one of the modes of OBD2 will show you strategies that on the factory side of OBD2 you may not ever get to see and then it's found on any type of scan tool I mean if you paid more than about $20 for the tool that you're using to diagnose cars pretty good chance you'll be able to look at the the 10 modes of OBD2 so that's another huge benefit as to why I want to use the OBD2 side of things as opposed to the factory side so at this point before we get any further what are the 10 modes of OBD2 so number one mode one is the powertrain info and sensor status so kind of like some data stream stuff along those lines number two is Freeze Frame data so anytime a trouble code gets stored and a check engine light comes on it's going to record the operating conditions of the vehicle so it may help you in your Diagnostics you know was this guy accelerating was he going 35 mil an hour you know was he just pulling away from a stop light all that stuff could use to help you diagnose or duplicate the type of problems that you're trying to to go ahead and address on that vehicle mode three is the missions related diagnostic trouble codes mode four is the ability to clear and reset those codes mode five are oxygen sensor test results mode six is onboard monitoring test results we're going to spend a lot of time on mode six here mode seven is emissions related diagnostic trouble codes during the current and last driving cycle so for the more experienced users in here this is great because we know that there's something that's called enable criteria and one trip and two trip faults and stuff and this is kind of like the old-fashioned general motor side of things where we had you know failure records that we could look at and it will help me prevent the time that's required to perform two complete drive cycles after I repair something to verify my repair mode 8 is your bidirectional controls if the car supports it mode 9 is vehicle information this is where you're going to find like calibration IDs from modules and stuff like that and mo 10 are permanent diagnostic trouble codes now what a permanent diagnostic trouble code means I'm just going to address that right now in the in this video is these are emissions related codes that were stored that you cannot erase with anybody scan tool the only way they're going to get cleared is by the computer running the test either one or two times times depending on the type of monitor that that code was set in and actually giving it the thumbs up that it passed it will not any stored permanent diagnostic trouble code will not cause you to fail an actual emissions test they will eventually clear themselves if you've actually repaired the car correctly continuing on what does the check engine light mean well the check engine light whenever that comes on on your 1996 or newer type of vehicle and technically if you want to split hairs there's a couple car lines from Ford and stuff that actually came out with mode 6 in 1995 the later had later half of 95 but anytime that check engine light comes on it's has a different meaning than what it meant in OBD1 OBD1 that check engine light could come on because the car was misfiring it was running poorly whatever the case happens to be when the check engine light comes on on an OBD2 car it means that it's failing the federal test procedure which is basically an emissions test done at the at the manufacturer by 1 and 1/2 times so it's exceeding the limit by 1 and 1/2 times so what that means is the car could actually be running good but it's polluting the air with the exhaust content coming out of the exhaust pipe also the diagnostic um link connector that is found it has to be within so many inches from the actual steering column on the car which is nice because in OBD1 like I said these diagnostic connectors could be located pretty much anywhere on the car and each one had a different look to it and you had to have all these adapters and so on and so forth now the trouble code that you may pull up on an OBD2 car may look different for us older texts and what we would normally be accustomed to seeing in OBD1 cars OBD1 cars we had a two-digit trouble code well if you look OBD2 went ahead and standardized the codes for us so the first letter that comes up tells you basically what type of module that this could possibly be coming from the next digit in that trouble code would be the actual type of code is it a manufacturer specific code which technically would be represented by like a one or is it a generic code like a zero which means that that's the same meaning on the same type of code no matter what type of Carline it happens to be then the third digit represents this affected system that's setting the code and then the last two digits again are the actual real trouble code just like how OBD1 was so it helps us narrow down our search our Diagnostics and then on the same slide we have this this little guy and this is how I like to explain mode six that little guy think of him as your computer and he's got that clipboard and he's he's a busy guy he's writing down he's he's keeping track of running the test results for everything he's making sure no two things are running at the same time that's going to cause one to possibly fail he's got a lot of notes on that clipboard and what we're basically doing when we look at some of these various modes of OBD2 is we're just peeking over his shoulder with our scan tool there and we're taking a look at his notes on his clipboard to help us diagnose these vehicles now we also have monitors and I want to just you know set the housekeeping rules up right now we have two different types of monitors we have continuous monitors and non-continuous monitors now the word continuous is a little misleading but basically we have fuel system misfire and comprehensive component those are constantly running as soon as I turn the key on so what that means for you drivability text out there is if there's a problem if I unplug the coolant temperature sensor or something like that on this car behind me it would immediately set a trouble code now why I say that's a little bit misleading is you notice that the misfire monitor is also continuously running so if I had a misfire and I think I fixed it and I erase the code and just turn the key on and the engine doesn't even have to be running it's going to say that the that that's a continuous Monitor and it's going to say that it has ran to completion well we all know that we need some we need some RPM on the engine to actually get a full test on that right but we also have non-continuous monitors now these are the ones that are harder for us as technicians to diagnose because this means even though the computer is constantly testing them it needs to see a problem occur not once but two times before it's ever going to set a diagnostic trouble code and in result turn the check engine light on so those would be like the two trip faults that's a common phrase that we throw around all the time within the industry those are the harder systems for us to diagnose that's where the power of mode 6 really comes in handy here so what is a trip and we said we got single trip and we got two trip faults so the single trip is hey those are the continuous monitors if there's a problem if I unplug the coolant sensor we use as an example well it's going to immediately store a diagnostic trouble code and it's going to turn the check engine light on but all those non-continuous monitors the EVAP monitor the EGR monitor you know the O2 monitors and all that kind of stuff all of those types of monitors I'm going to have to be driving I got to meet the enable criteria which we haven't talked about yet but it's coming up I I promise I got to meet the enable criteria twice and it computer would have to have wrote on his little clipboard that there was a problem both times before we would normally ever turn a check engine light on or set a diagnostic trouble code so those would be the non-continuous monitors think of it as the two trip fault ones and the continuous monitors those are one trip faults so some common terms I'm just going to Briefly summarize these I'll go into more detail on a couple of them but trouble code I don't think we got to spend any time on that monitor we just kind of talked about that in pretty good detail task manager diagnostic executive whatever the car manufacturer wants to refer to it as that's the software of OBD2 think of it as that little cartoon guy with his clipboard right trip we already just talked about what that meant failure records we haven't talked about in great detail yet a failure record is anytime I go ahead and I have a problem that occurs right so I failed the test result of some sort well that's going to be registered as a failure record and depending on the type of monitor that that came from it's either either going to if it's a continuous monitor immediately matur it into a diagnostic trouble code turn the check engine light on or it's going to keep that as a record and it's going to let us know that hey if the next time I run the enable criteria for this particular test and it fails again well now it's going to mature into a diagnostic treble code Freeze Frame data we talked about once a code is stored it's going to write to Freeze Frame data now every single car manufacturer out there no matter what vintage it is will always have at least one Freeze Frame record stored now if there's two problems with the car you might say well which one does it actually write from it writes to the one with the highest emissions related trouble code priority so so if I had a misfire code and possibly a bad cooling temperature sensor code well the misfire code would be the one that has the higher priority so it's going to write to it now some of the later model cars some of the other manufacturers they can write multiple Freeze Frame records but freeze frame is a great thing to look at to help you determine you know how is this car being operated when this fault actually occurred enable criteria I'm going to come back to because I've got a whole slide because that's very important I also have suspend and conflict these are going to be two things and we're going to talk in more detail about as well but these are conditions that will prevent a monitor from running so doesn't make a whole lot of sense yet but I promise you it will here coming up shortly so what is enable criteria and I'm not going to read this word for word but I purposely chose a p0440 as an example 440 is kind of like a p300 it's just a you've got a problem in this system doesn't really give you any kind of diagnostic Direction so we know that 440 represents the evaporative Purge Monitor and I actually took this from an information system this is how you had to this is what the that little computer got this is how you had to drive the car the operating conditions this is the little computer guy that has all of this stuff memorized so that he sees that when hey when all these conditions are met it's time for me to run the EVAP Monitor and I'm going to you know grade it and give it a pass or a fail so the first five words there no Engine Systems codes were set so what does that mean let's talk about this and this is the diagnostic mindset that I always am always referring to in these videos that means if I had any type of any type of trouble code stored for you know we've been saying you know cool and temperature sensor so I had a a cool and temperature sensor related trouble code that means the computer that little task manager diagnostic executive that little guy with the clipboard would see that and say well I'm not even going to run the evat monitor makes sense however keep this in mind so let's say you had that scenario come into your shop and you put a new coolant sensor in the car and you test it and you're like yep it's fixed I'm going to give it back to the customer well that could cause a comeback to occur it may not be your fault kind of is kind of isn't it probably isn't going to be for the same sensor that you just put in but now that the computer says hey there are no trouble codes you know um Billy the mechanic over here went ahead and successfully repaired that cooling temperature sensor so at that point I can go go ahead and check that off that there's no trouble code set so now let me run the test on this and if it fails something in that test well now the check engine light's going to come back on try to explain that to the car owner that hey you brought it to me because the check engine light was on I told you what it was going to be I fixed it you paid me money now in your mind who knows nothing about cars you're bringing it back to me for the same problem check engine lights on even if I tell them no it's for a whole different code well that doesn't make sense to them right which is understandable they're not professional techs then the barrel had to be over 70 kilopascals ECT and IAT had to be between 40 to 86 degrees to start up all of this stuff fuel tank levels had to be between 15 to 85% fuel in the tank throttle angle had to be between 9 and 35% if all of these conditions were met then it would be okay for it to run the EVAP monitor now remember that's a non-continuous monitor so even if it failed something in the monitor it's just going to take a note on his clipboard and then it's going to come back and the next time all those conditions are met again then it would if it failed again it would actually let us know as technicians by being able to set a code and pull the code out you know all that kind of stuff so that's what makes it hard is this whole enable criteria which is driving it because this is just one example there's hundreds of codes on a car and there's many different operating um modes and and actual component strategies and everything that we have to drive different types of conditions for so with all these different monitors that we're trying to run it becomes sometimes very difficult to run and drive the car properly to get the diagnostic test results that we're after so enable criteria is a big deal now couple other things to remember to avoid The Comebacks as we were saying dep pending suspend and conflict so these these are three reasons why that little guy with the clipboard can stop running and monitor even if all the enable criteria is met so for instance one example would be I have an oxygen sensor and it's in heated oxygen sensor and the heater element in the oxygen sensor is failed well it doesn't make sense to run the O2 test if I know that I something that I need to actually have a successful pass and think about how an O2 sensor works got to be 600° Fahrenheit you know I I get it the exhaust gas temperature will eventually raise it up to 600° fah but we rely on that heater during cold startup mode to get it up there so if that heater had a a failed circuit in it and we failed the O2 heater monitor well the computer's not going to actually want to run the O2 test because it says well I need this heater in order for the O2 to work right so again this all goes back to hey you know if we don't understand how these systems work we could actually maybe in OBD 2's case actually fix whatever the code was or whatever the one thing was and not understanding how the system is designed to work all of a sudden this vehicle comes right back into our shop you know a day two days later with another check engine light on could possibly very well be for a whole different code but again the car's owner does not understand that right so as far as they're concerned ER this is a free repair by by your part at this point because they brought it to you the first time for a check engine light and came back so let's talk real quick about some monitors right I'm not going to talk about them all I'm just going to talk about the most popular ones and when we hook up the scan tool we're going to you know refer back to these so we have a comprehensive component monitor we always had that even in OBD1 so if I had that coolant sensor that we keep using as an example and I unplugged it on an OBD1 car I would set a trouble code what we couldn't do in OBD1 is we could set codes for for sensors but we couldn't set codes for output devices and a lot of times that's why in OBD1 we were told diagnose the lowest number code first right because sometimes they would actually have a tendency to fix some of the higher number codes at the same time and a lot of times we might set false codes because let's say we had a solenoid that was shorted and the computer looking and it says well I can't set a code for a solenoid but you know the ground circuit for all this stuff was on something called a quad driver so I look at my list of four possibilities and I find something I can set a code for so I'll set a code for that because I know there's a problem on that circuit because I wasn't Advanced enough to set an actual trouble code for what was wrong with it so we now have the ability to set for not only inputs but also outputs and then plus we can actually actually test it for rationality here where rationality is something I could never do before so if I had a bad coolant sensor and it was saying it was 40° outside or 40 below let's say because let's simulate an open condition but all my other temperature and barometric pressure related sensors are all telling me this guy's lying right because we're not that cold it's not that cold out well I'm going to rationalize that that coolant sensor's got a problem now let's talk about the misfire monitor as long as that crankshaft's spinning at the same speed anything that causes that crankshaft to slow down could indicate that there's a misfire present now we don't want to set false misfire codes so what it will do is it will look at the rpm sensor to measure the speed of the crankshaft but then it's also going to look at the oxygen sensor signal at the same time cuz if a misfire did in fact occur there's going to be extra oxygen present because the oxygen wasn't burned up inside the combustion chamber so if I see a Slowdown in RPM plus a whole bunch of o2 after that slowdown coming across my O2 sensor then that little guy with his clipboard can safely assume that hey most likely there was in fact a misfire that occurred then we have O2 heaters right and this is pretty self-explanatory we're just going to start a little stopwatch and we're going to see how long it takes for that car to go into Clos Loop now in the oldfashioned days it had to be 600° fah still has to be 600° Fahrenheit except we're not relying on exhaust gas temperatures to do it we're relying on the heater element inside that O2 sensor to actually run that monitor the O2 test itself well now this is where it gets a little bit um a little bit exciting for us right so basically there's an there's a picture of an oxygen sensor pattern now you might be saying to yourself if you're an experienced Tech hey modern-day cars they don't use an O2 sensor like that they have something called the lean air fuel ratio sensor well one of the benefits to OBD2 is I can still pull up stuff that I've been accustomed to seeing so I can still read 02 molts on the global side of OBD2 or generic side whatever you want to call it so I got that I got that waveform and it's switching up and down like I expected to the amplitude represents rich or lean but we also needed to switch richer lean in a certain amount of time because if it doesn't switch high enough richer lean or if it doesn't switch fast enough richer leene that's all called cross counts I'll come back to that in a second well then that sensor has become biased right so if it's biased rich or biased lean or if it's slow to respond these are all types of trouble codes that you can actually pull out on your on your scan tool and have to be faced with diagnosing it so that rule of thumb is it has to switch Rich to lean in 100 milliseconds or less as long as it does that then it's going to pass this test now what is a cross count so we're going to just keep it real simple back in the day it was not it was pretty much normal for the computer it was a single wire O2 sensor and the computer would go ahead and send 500 molts or a half a volt down on that signal wire and then as that sensor heated up and it was measuring exhaust content you know it would either pull that voltage up or pull that voltage down so the cross count is just whatever that voltage that initial voltage on that sensor wire happens to be being sent there from the computer if You' never known that before next time you're replacing an O2 sensor go ahead turn the key on and have the O2 sensor unplugged and go to that that signal wire and measure the computer side of it and see what that voltage happens to be now the Catalyst monitor which is basically using another oxygen sensor it's going to be comparing the pre-cat O2 sensor to the postcat O2 sensor and it wants to see that that signal is 30% or lower than what the pre-at is so that's the rule for setting a faulty Catalyst on OBD2 types of vehicles so with that being said we got a fuel trim monitor the next video that's going to be coming out is all going to be on fuel system so we'll be spending a lot of time on this but the fuel trim monitor this is the ability to test the car's computer that if it's seen that it had a lean exhaust content to be able to Rich up that fuel mixture so that we can go ahead and make the catalytic converter work the way it's designed to in Parts one and part two of this diagnostic series we kind of talked briefly about catalytic converters we'll revisit that when we go over five gas analysis we also have EGR monitors EGR monitors if the EGR is working the way it's supposed to and it opens up well then the engine vacuum should drop right so this is how these EGR monitors are designed to work we also have an evaporative Purge Monitor and there's two main types whether we're using in in one way or another we're changing the state of pressure in the EVAP system we could either go ahead and do it with pressure itself kind of like a leak detection pump from a Chrysler system or we can use a vacuum it doesn't much matter in a nutshell what we're basically doing is we're saying that hey gasoline has a readed vapor pressure so it's kind of like if if you've ever had your own lawnmower gas cans back in the day we used to have the little vent on them because on a hot day temperature has a big increase on Reed vapor pressure from gasoline so those expanding hydrocarbons would just vent out to the atmosphere on old-fashioned cars they did the same thing right in the fuel cap then in the 70s and in some cases the late 60s they started putting canister canisters on these vehicles so that the next time we start the car instead instead of venting those hydrocarbons out to the atmosphere we would just suck those hydrocarbons out of the canister and reburn them we also have an air pump monitor on some cars it's not as popular as it once was but again in order for us to test this air monitor we're just going to be looking for the extra oxygen that the air pump is pumping into the exhaust stream when the vehicle is commanding it to do so we're going to be looking at the O2 sensors to see that extra exhaust content a thermostat monitor you know there was a time when we had no way of knowing if the thermostat was bad on a car now we set codes for it all the time we're just testing this at Cold startup right how long does it take for this engine to reach operating temperature before I'm going to set a trouble code PCV monitor if the PCV system is is restricted whether it be the Breather side or there's a bunch of sludge in the system whatever the case happens to be well PCV valves operate off of of a vacuum hose so we're going to see that that is affecting the vacuum there now that we know what basic monitors are let's talk about the drive cycle this is why it's hard for us technicians to always be able to drive these vehicles the way the computer needs it to be driven to test these various monitors so we know if we have a fault or not so we have a generic drive cycle displayed and it tells you how you got to drive it for each one of the each one of those boxes but I made it a little easier for everybody to see off YouTube there and I just took a little Ford drive cycle and there's there's various drive cycles out there so if you wanted to see a specific drive cycle for a specific type of car look up what that drive cycle would be on your information system here's just a generic one without electronic automatic transmission I'd have to have idle mode for at least 6 minutes um quarter quarter throttle acceleration then drive the vehicle at 30 to 45 mph for at least 4 minutes then DXL for at least 1 minute then 40 to 65 M an hour for 80 Seconds you know the with the half throtle opening there um then Dell and idle so as you can see this is why dinos became such a big deal because how can traffic allow me to drive under these conditions and it kind of would make sense here if you know hey in order for the you know the Catalyst monitor to actually work the way it's supposed to be able to test that extra oxygen and make sure that the catalyst is heated up to the proper temperature that has to be done at highway speeds so if I had a cat related type of code a catalyst code well now I know I'm going to have to drive the car under these conditions plus I'm going to have to look up the enable criteria to make sure that everything else is met at that point so it's hard to drive it under these conditions the good news is if all of a sudden somebody pulls out in front of me and I have to slow down it's not going to make me start all over again it's going to remember what I've done that far so then the next time I meet those driving conditions again it's just going to pick up where it left off so that's a nice feature that helps us out so now that we know the different types of monitors on a car a lot of terminology and stuff what I want to do is I want to take a scan tool because there's some important stuff that we need to cover with the scan tool if your scan tool is asking you anything about the car the year the make the model the VIN number any of that you're going on the factory side of OBD2 you're not you may or may not see what I'm about to show you so I select just on the alt's case it's a little Orange Engine and it says Global OBD2 now I can either select the protocol or I can do auto scan so I'm going to do auto scan now on the left hand side of the screen it's going to ask me to choose the functions those functions these are the different modes of OBD2 that we were talking about mode one mode two all the way through mode 10 we're not going to spend a lot of time in each one of these functions but I'll just kind of briefly pull up the different ones I'll click on these buttons as we go here so if I go into diagnostic trouble codes here it's going to say there are no codes detected that's because there's nothing wrong with this car just using it for demonstrational purposes here but I could read the codes I could erase the codes and also Freeze Frame data is grouped in there as well but since there's no codes then there's not going to be any Freeze Frame data because that's the only way you're going to have Freeze Frame data is if there was a code store if I go into I am Readiness well anybody that lives in an emissions related testing type of State you know what this is all about this is hey I can't just erase the codes and take it right up to and get a get my emissions tested because the computer hasn't had the opportunity to run all a test to determine whether or not there's a fault in the system here's a quick way that I can go through and I can look at this for I Readiness here and I can say okay I know if a check engine lights on it's telling me it's off malfunction indicator lamp it's telling me if there is any type of problems that I might have regarding any of these now I finally get down to the actual monitor Readiness status here so the misfire monitor says it's okay okay in autel terminology means it's ran it has not found any type of fault so it passed that it's ready to go on to the next monitor if it said in complete or or not applicable or not okay or whatever your scan tool terminology has to be that means I couldn't take it in for an emissions test because the computer hasn't ran that test yet diagnostic clue if it's a non-continuous monitor don't ever give that customer their car back if it came in and you thought you fixed something in a non-continuous monitor because you don't know if it's fixed yet or not the computer hasn't ran the tests on it yet I can just see all the different monitors it tells me if they have ran or not ran yet also lets me know if there's any type of faults or trouble codes found in any of them now if I go down to the next one for the live data well here's where I'm going to see my data it's just like if I was on the factory side looking at data I'm going to pull up a couple things to point out and give you some diagnostic Clues when you're using this it's in heximal code which is why if you're wondering why the dollar sign's there each one of these has a heximal address the lines of of data have a heximal address the modules have a heximal address when you decode a can signal which again is going to be in a future video this is how you can actually determine which module's talking on that can Network at a time but the hexo code that dollar sign doesn't mean hey you know it's a Payday or nothing like that that's just the actual address notice here's something I really like about the autel because it tells me what the current value is in the First Column but then it also tells me the range now that range is coming from mode 6 which we're going to get to mode six here in a second second but that range is telling me what it's supposed to be so how can I use that range well let's say that I I have an intermittent type of problem the guy says hey it stalls occasionally or it runs rough occasionally or whatever I bring it into my service Bay it's not running rough I can formulate an attack plan in my head and I could say what could cause it to run rough you know the most common thing would be a misfire so I can go look and I can say hey you know what this one cylinder it's still technically in the range which is why there's no coat or nothing set yet but look how close it is to being out of that range so would and if it did go out of the range would that cause the customers complaint let's say you determined you had a bad coil pack you put a coil pack on well it should definitely be within range at this point the first couple numbers there that says numbers of dtc's those dollar sign and S um EA and 7 EB those are different types of modules so module engine controller module so on and so forth so I'm going to going to scroll on down here and notice that just like with every scan tool I can graph stuff if I wanted to I can change the values from Imperial to metric or whatever um you know I can make the coolant temperature sensor an actual gauge if I wanted to or I can say you know I don't like the look of that gauge I want to graph it instead you know so this is just pretty much Universal with all the different types of scan tools but again not really a scan tool class yet so not going to spend a whole lot of time on that but I have a lot of good information available for me I got fuel pressure reading I have engine RPM but all the stuff that I wanted to kind of point out here is this is all real data so there is no substituted values here if there was a fault in any one of these even if General Motors said well we want to give it a substituted value I'm going to read the actual values on the global side of OBD2 whether it be for you know intake temperature sensors coolant sensors you know RPM I don't care what type of pit it is it's going to be live data now we also have I said before that even though this car has Lan a fuel ratio sensor notice that I have my oxygen sensor output voltage here so here this is Bank One sensor one so I'll just graph that so we can kind of see it so even though I'm not looking at pumping current and stuff I can still look at the stuff that we've talked about and if I understood that hey when it's high that's representing a rich condition when it's low it's representing a lean condition and if I wanted to pull up the Catalyst sensor and then speed the engine up you know I can compare the two signals and based off everything we just want over on the slide presentation there you understand how these systems are supposed to work and what the testing criteria is in the examples of the of the different monitors that I used as an example in the presentation there of what that little guy at this clipboard is actually looking for right so now let's go on down to onboard Monitor and onboard monitor this is where I'm going to find my mode 6 data now here's the deal with mode 6 mode 6 is something I've been involved with since the late 90s and I can remember doing a lot of mode six classes and the theory was oh it's a waste of time it's an engineering mode and all this stuff but mode 6 has evolved into something that everybody thinks is the same save all for everything so back in the day I would tell people hey you know it's not for just Engineers there's got a lot of diagnostic information available to us as a technician that could help us diagnose a car but even today I tell people it's not your Saving Grace it's not the only thing you need to understand to be able to diagnose a car it does work really well on certain types of certain types of faults but if I look at this again it it's heximal coding so each one of those lines of data have a hexadecimal address so the first one rich to lean sensor threshold voltage um Mid that's monitor identification tid would be test identification if it's an older car it would be test identification and Sid for component identification so I'll come back to an explanation of that here in a second but now it tells me the thresholds from column number number three over so what the minimum maximum testing thresholds were and then what my current value was how it's being read so it's being read in pressure and voltage and temperature whatever and then whether or not it's actually passed or failed it so just looking at the first one there's a ton of diagnostic information here so number one let's talk about the mid or Sid and tid and all that go ahead and revisit that p0440 code for a second that that told me I had a problem in the EVAP system well we know there's a lot of components that make up an EVAP system you got Purge solenoids you got vent solenoids you got depending on the type of car you got all kinds of stuff right well let's just make it simple and say all you had was a purge and a vent well instead of just giving you a generic code like that wouldn't it be nice to be able to diagnose this and break it down closer to the Circuit so a circuit could be maybe the the canister purge circuit or something along those lines well that heximal coding there every one of these components has its own address so this is where this becomes so valuable for us because now we can take a random code right away and we can say instead of looking at the entire encompassing system I'm just going to go ahead and focus my attention on that circuit now when I get that circuit we use as an example a canister vent I believe um that doesn't mean that that sensor is bad it means there's something wrong with that circuit there could be a hose unplugged there could be the wire con connector unplugged there could have too much resistance in it whatever the case happens be but at least I can focus my attention in one area now the actual values minimum maximum and my current value boy my diagnostic mindset goes nuts with that because I say I know how it's supposed to work I know the range so now if it's outside of the range whether too much or too little whatever the case happens be I now can go ahead and use this information to not only help me diagnose the car but also verify the repair because if I replace something or I fix something it should now definitely be within that range should be comfortably within that range also if it's an intermittent problem even though the problem's not showing up right then look through that range and say well technically this one's in range but it's very close to being out of range and now if it did go out of range would that match the complaint that the customer brought me their car for if the answer is yes concentrate on that that scenario now I will say this here's the little precursor this is not live data now some cars is pretty fast so I can go ahead and use it almost as if it's live data but this is not live data sometimes you need to have the car shut off and then start back up you know in order for you to in order for remote six information to update so keep that in mind but it also is beneficial that it's not live data in a way because now the customer has an intermittent type of problem you bring it into your shop and you see that hey everything is saying that it's passed um but let's look at those ranges right and one of them is very close to being outside of that range so it's going to help you diagnose these cars better so mode 6 is a very valuable diagnostic tool primarily for non-continuous monitors now everybody out there is pulling their hair out right now because I'm going to get a ton of comments saying it's also great for misfires I agree with you 100% it is great for misfires because not every car has a misfire monitor in mode 6 they graciously Incorporated in the misfire monitors for us so I have that misfire data now misfires we know is a continuous monitor but remember what I said way earlier in this whole video that even though it's a continuous monitor we don't really know if the if it passed the misfire monitor even though it says it did and everything's okay until this engine's running also if you really want to split hairs oxygen sensors should be in mode five shouldn't be in mode six but most manufactures Will Group it in with the mode 6 information so it's great for O2 testing it's great for misfire monitors it's also great for the non-continuous monitors and I can use it to help me verify that I actually repaired it because I don't have to wait for that little guy's clipboard to run the test two times as soon as he runs a test once he's putting these notes on his clipboard that's what I'm looking at right now in mode 6 think of it that way I'm looking at his clipboard he speaks in computer talk which is why there's heximal code and all this other stuff here but I'm looking at his notes so I don't have to necessarily make it run two times to verify that I've repaired a car now I have my actual component testing there um that would be your bir directional controls this particular vehicle is not going to give me anything in there so I'm not going to click on it my vehicle information I want to pull that one up though tells me to turn the key off I'm just going to try to lie to it to save time here I have vehicle general information I have vehicle enhanced information onboard fuel consumption monitoring so let's just go to vehicle general information just so you guys kind of got an idea here's where this would be mode 9 all my calibration IDE s right for the different types of monit or different types of modules on the vehicle if I had to do reprogramming or maybe I'm checking technical service bullettin and it says that there's an update and the latest update has this Cal ID well here's how I know if that update's been performed yet or not now if I go down to vehicle status we'll let it do its thing there and establish it again this is telling me an overall snapshot a bunch of information all about the vehicle here it's telling me the different types of modules that the vehicle has access to and it's also giving me the heximal code there and it identifies those modules so when we get to the video that talks about you know diagnosing can faults and stuff like that that becomes very valuable because we can decode the can signal we know which modules talk and we don't have to just start unplugging modules trying to figure out what's causing the communication type of fault now I also have the fact that it says that the mil light is off right it's not illuminated there's no trouble codes all the monitors are saying that it's okay there's a couple monitors that the car does not support this is how we're going to pretty much be wrapping this video up here there's no incomplete monitors there are eight monitors that actually the car does support and they've all ran a completion but if this car was sold say in Canada or something I might have a heated cap monitor it's still on that guy's clipboard but he knows that this car does not have a heated cat so even though I might come up and say heated cat is incomplete well that's because it doesn't exist on this particular car okay so with all that being said this was part three of our diagnostic series here and again 85% of the the Diagnostics that I do that's drivability related all end up being used solely in the global side of OBD2 I do go on the factory side we'll talk about that as more of these series go by our next series I kind of already let the cat out of the bag our next uh video in this series I should say is going to be on fuel systems My ultimate goal is to somehow relay you know my years of experience for Diagnostics I couldn't do it all in one video because the video would end up being you know a month long and no one's going to sit there and watch that so even these videos are kind of long and I appreciate you guys watching I also appreciate all the comments you guys are putting in on the YouTube channel channel for me because this lets me know if I'm doing a halfway decent job for one but also lets me know that there's interest because obviously I don't want to be doing this if nobody's watching the the videos if nobody thinks it's any good please like and share you know go ahead and set that Bell I don't even know what that Bell means but somebody in the comment told me hey I got I set the Bell so that it rings every time there's a new video so that sounds like a good thing so go ahead and do that right I appreciate your support and I look forward to seeing you in the next video again which is going to be all about diagnosing fuel systems

Channel: Electron John - The Drivability Guy

Views: 11,608

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Id: TN9ZyIW_ZJg

Length: 47min 3sec (2823 seconds)

Published: Wed Feb 14 2024