Honda Pilot Flashing Check Engine Light (P0303 Cylinder 3 Misfire) Diagnosis

[Music] all right we got a Honda Pilot here with a flashing check engine light see if we can get this thing fixed all right first thing we'll do we'll go into our scan tool we're gonna read the codes now usually a flashing check engine light it's gonna be a misfire and I I could feel a little fish bite in this fire when I pulled it in so I'm pretty sure that's what we're going to find and yes we do have a misfire when we get it on cylinder three p0 303 misfire so we will go back and oops went back to mini we're going to go into our live data we're going to look at our misfires see how many we're getting a lot of data here okay there's our Miss Claire's alright we already got some right there on cylinders three counting up you can see Friday at nine and I can definitely feel it every time it misfires I can feel just a little bit of a fish bite on the steering wheel it's counting up pretty decent so we have a pretty steady misfire not every revolution of the engine but it's definitely there quite a bit all I'm thinking of Honda has two thresholds for misfires one is basically if it's going to damage the catalytic converter so that would be considered a severe misfire so basically if it's misfiring every every time the engine goes around and then they have a less or less severe misfire and it will just set the check engine light but it won't turn it on so basically for every 200 revolutions the thresholds I would have to look up the numbers but it's usually anywhere from 30 to 90 misfires on a cylinder in 200 revolutions it will set the flashing check engine light and then if the if it's every 1000 revolutions if it hits around 35 or 40 misfires then it'll just set the check engine light but it won't flash and so right here this cylinder misfire right here this will be what the computer looks at for a flashing check engine light and if we can find cylinder B right here this B this would be for the less severe misfires and so that's what this counter is so basically if we want real-time misfires we're going to look up here at this one but when you look at a scan tool if you see them both that's why there's a beat and just a regular that's what the engine computer is looking for to determine whether it wants to just set a check engine light or if it wants to flash it you can see that it will reset but you can see our misfires are definitely counting up pretty good so let's go under the hood and take a look all right as you can see with the hood popped open this is a 3.5 liter v6 you can see it has the Ivy Tech with BCM or variable cylinder management I'm just gonna pop this cover off I'm just gonna twist that one and this one right here and we can lift this thing off all we got to do is turn it like that we should be able to just pop it right off now just a couple of little rubber type clips in there and we can take it right off all right that's what it looks like with the cover off pretty standard Honda J Series v6 this is a 3.5 liter there's our belts over here so that means this is the front of the engine we got cylinders one two and three in the back we got cylinders four five and six in the front here so that's gonna be Bank one is back there this is bank two just so you can kind of get the orientation a firing order on these it's gonna be one four to five three and six and that's pretty much standard on all the J Series that's going to be the firing were these particular ones and most of the newer ones are going to have VCM or variable cylinder management that basically means it's going to deactivate the cylinders at certain time or certain cylinders at certain times so it can run in three cylinder mode and when it does that it's going to deactivate one two and three back there and it's just going to run on four through six up here or it can run on four cylinder mode which means it's going to deactivate cylinder three and cylinder four and then it's just going to run on one two and then five and six or it can run obviously in six cylinder mode at idle and acceleration it's going to run in six cylinders lower cruise and more steady speeds at the lower end it's going to run in three cylinder mode higher cruising and steady and steady speeds it's going to run on the four cylinder mode and when it does activate the VCM you'll see the little echo light up on the dash so basically these engines can run as a three a four or a six cylinder it's it's doing this by deactivating the fuel injectors at those certain cylinders and and it locks up the cams so that the valves stay closed so the valves do not open and close when they're deactivated and unfortunately VCM can cause a tschüss it can cause excessive oil consumption and obviously if the oil gets too low can damage the do some damage to the engine especially the cylinder walls the pistons can kind of vibrate and realign the Rings and obviously that's not good that's gonna allow your compression to fail and more oil is going to get up into the spark plugs and fouled spark plugs is a big issue on these so those are the things you got to kind of think about when you're working on these v6 is now Honda did update the software to kind of combat the issue but these problems still remain even with software updates which kind of limits how how often these cylinders switch on and off because some people would kind of just bury you know lightly go a little bit on the gas and off and it would cause the VCM to activate deactivate activate deactivate and that really caused excessive oil consumption so they kind of fix that issue but the oil consumption and the foul the plug fouling still remain so as you can tell I'm not a real huge fan of the variable cylinder management on these things but anyway let's see if we get this thing fixed okay so where do we start then now thinking logically Honda's historically have not had fuel delivery issues now I know the newer 1.5 liter turbos with direction with direct injection if I could say it right they have fuel dalish dilution issues but as a general rule Honda's don't have fuel delivery problems they're pretty reliable so I'm not gonna start there I know other manufacturers do and if this wasn't a Honda maybe we would have to start there but it's a Honda so I'm not gonna worry about that right now I think we'll go we'll keep it simple and we'll go for the ignition coils first and instead of breaking out the fancy schmancy equipment we're just gonna swap coils well we'll make it easy something you guys could do at home they're just gonna swap the coils I know I used my expensive scan tool to look at the misfire data but the cheaper code readers don't show that or they typically don't show that data so that's why I had to break break out the big scan tool so we're going to take the number three over there that coil we're going to swap it with the number four now as I showed with the firing order they're not right next to each other in the firing order so that's a good swap and then so what we want to do is we want to look at the scan data and then we'll see did our misfire stay on number three or did it move over to number four and the way that ECM or the way the ng computer determines misfires is the engine computer is looking at the Krantz crankshaft position sensor and basically on each firing event it wants to see that crankshaft sensor move and send a signal back for at a certain you know speed and a certain time frame when it takes too long it's going to interpret that as a misfire it's not an exact science so you know we need to take it with a grain of salt and what we don't want to do is is swap the coil with a cylinder that's right next to it in the engine or in the firing order so that's why we're gonna swap it with the number four because it's right now right it's man I can't say it it's not right next to each other in the firing order so it's a much more valid test now even though one of the symptoms from variable cylinder management is it could damage the Pistons we know that and cause the Rings to get screwed up but it can also cause excessive oil consumption and so the first thing we want to do let's make sure this thing is full of oil we don't want to make sure or we want to make sure this thing's not well and that's contributing to our issue now this thing is full all the way up to the top of the grids they're so low oil is not a problem and the oil looks clean so this thing had the oil changed not too long ago for sure you gotta kind of feel for it back here but the coil like I said is way back here I can't even see it I'll just loosen up the nut try to take it off without dropping it and then we'll get the coil out all right there's one coil it looks used but I don't see any issues now we'll pop the number four out do the same thing loosen up the nut and take it out and it's easier to pull the coil out just a little bit and then unplug it there's our number four actually looks in a little better shape than our number three but pretty similar so we'll just swap them I'm not even gonna bother putting the nut back on we just swap it fired up and see if our misfire move and I know it's kind of hard to see I can't forget for a good camera angles but you can see you know if you're pulling these coils out you just pop the the nut off just like that we can the coil out pinch the tab and take it off pretty easy and you can see there's number four five and six coil right here I'm the back side of the engine they're back in there if I can feel them there's there's number one right there number two and then number three is way over here under all this stuff definitely hard to get to and you just gotta got to do it by feel all right we're gonna do the same thing as before we're gonna go into live data fire up the vehicle and then we'll look and see if our misfire moved I anticipate that it's not gonna move because like I said coils usually this vehicle has 90,000 miles usually Honda coils don't fail at ninety thousand miles although it's not unheard of completely but I suspect we're dealing with a problem with the variable cylinder management and plug following issues like that from the excessive oil consumption due to that so there's our misfires well fire this thing up and look and see where see if it moves to either three or four no misfires maybe we've fixed it no probably not you can see if we're counting up already on number three so no our problem did not move you can see right there you're counting up pretty steady so it's definitely not a coil problem so let's see what do we do next alright in order to keep things simpler what I'm gonna do is I'm gonna pull the number three spark bug we're gonna take a look at it I suspect it's fouled up that's a common issue on these and if we think about it when it's running in three cylinder mode it deactivates one two and three when it's running in four cylinder mode it's deactivating three and four so what's the common denominator that's right number three so that's that's on these with the variable cylinder management that can go both you know three and four cylinders that is our problem child all the times right there number three so I suspect we're gonna find it all fouled up and then we want to compare it maybe it is number four and maybe number five over here and see what the difference is we'll just reach back over here get our all right using safety glasses I'm gonna blow out the cylinder before I pull the spark plug this in case there's any garbage in there I don't want to drop it down into the solder alright here's the setup I'm going to use to get the spark plug out it's just a standard 5/8 inch socket for spark plugs it's got a magnet at the end there it's got a little swivel this one has a short extension and then I'm using a long extension that locks in so I won't pull it off here's another one from gearwrench you can see this one's longer but it's a little too long you can see trying to get back there there's some pipes and stuff this will definitely not fit and get you trapped in there so I'm gonna go with this to break it loose a little tight back here you can see I'm using to flex it to because there's not a lot of room in here well there she is can you see it and you can see that's pretty pretty oil filed it's hard to tell but it looks like the gap has opened up a little too much I suspect these are the original plugs but yeah it's definitely just at first glance it's definitely oil soaked and yeah I know it's a little weird the VCM can cause it to use excessive oil but yet it can starve the Rings and cause problems and score the inside of the cylinder wall so if I mentioned it or if I didn't mention I'm not a fan of the VCM we'll just mark this one number three and we'll pull the four out see what it looks like also alright now for the number four this is the setup I'm gonna use so I'm going to use the gear wrench with a little bit longer built-in extension and then I got to use the little one and a half extension just to get it a little bit longer but the other one is too long so this is a setup for everything up here see and we'll just take our spark plug with the extension just set it down into place like that and you can see it sticks it out in a good spot for us to get a ratchet in you can do it there we go now if I didn't mention it I don't advise taking these off when the cylinder head is hot so if the engines hot weight good rule of thumb is when the cylinder head temperature is at least a hundred or below it's above a hundred I wouldn't take them out till it cools down below 100 let's see if I can no I'm not gonna try this one-handed I'm gonna hold it with two so I gotta set it down and there we go this one looks like it's in a little better shape but it it's still oil file just like the other one but not as bad all right I'm gonna mark this one number four and we can compare them we can look at the two you can see this is number three this is number four I'll turn them to the side so you can get a good look at them gentlemen you can see it's leaving oil on my glove but this one looks in much better shape that one looks pretty normal and yeah just judging by how they look I'm pretty sure these are the original ones but this one is definitely oil soaked and fouled because of that so I believe we found our misfire right there it's a fouled oil our fouled plug because of oil the gaps look pretty much the same this I think it's just it gives an appearance because of the way it's built up that it might be you know opened up a little bit but I believe they're the same all right now if the plug is indeed causing our issue which I believe it is but it it's a symptom of the variable cylinder management doing what it does but in order to fix this today I believe it needs a new plug but we can confirm that by just switching them so I'm gonna put the number four back over there and I'm gonna put the number three in the number four position and we'll fire it up and see if our misfire moved to number four all right number four all right take our number three say we got it mark all right I marked the coil that came out of number three we're gonna put it back in its original position that way the only thing that will be moved is the spark plug itself all right I'm not gonna put the nuts back on the coils right now we'll just fire it up and see if our misfire moved right there's our misfires let's fire this thing up and see if see if our misfire moved if it stays on number three we got bigger issues no you can see we jump to number four so our diagnosis is correct they needs a new spark plug at least one in reality it's going to get six spark plugs but one will fix it right now but there's no guarantee this issue won't come back because of the variable cylinder management all right here's what's gonna fix our problem today brand new NGK laser Iridium spark plug this is exactly what the OEM plugs are here you can see the part number that's what it is for this vehicle of course you always check for what vehicle you have but that's what it looks like and of course so that's what it looks like brand new so I'll put this one in and you can see I'll just pull this one out this bad one and put this one in you can see the fix and then I'm gonna replace the rest of them all right there you go that's what the brand new plug and the old one looks like you can see how oil filled that one is and how soaked it is the gap looks like it's a little bit wider on the old one that's not to be or I mean that's to be expected given the age but so that but that definitely could be contributing to it that gap opened up a little more plus the fouling on the plugs but I suspect 90% of the issue why it's misfiring is the fouling on the plug so put the brand new one in there and we'll make sure that misfire goes away and whenever I do plugs a little bit of dielectric grease right on the boot there and if you're curious here's the number five I pulled the number five spark plug out I'm just going to go ahead and do them all right now and you can see the difference that number five looks really good really good for ninety thousand miles it looks excellent if if Honda would allow us to disable the DCM either with the you know instrument cluster or the for a scan tool these engines would be a lot better number six spark plug right there looks good and you can see there's number two it's not far behind number three this thing is getting ready to misfire also there's the number one spark plug see pretty close to number two so not as bad as number three but not great you guys you do have to use a little bit shorter setup to get to this one cuz the AC lines are in the way and I know there's some controversy on the subject but when I install the spark plugs on these Honda's I put a little bit anti-seize you can see right there I have some on there I know NGK says you don't need it when did it'll affect the torque honda tells you to use some and then gives you the torque spec so I'll go with Honda on the torque spec on these is once you crush this gasket so you have two on these this model it's about a quarter turn to crush this gasket on others it's different it might be an eighth it might go all the way around to you know like from noon to seven o'clock so just depends on the spark plug but these it's about a quarter turn to crush this and then it's 16 foot-pounds and for the most part you can get a torque wrench on mine has a flex head and that's why I can get in there just a straight one may not be able to do it it's tight but it's doable all right all the spark plugs are replaced all right now that that's back in place let's go see if this thing runs right all right as you can see you got the misc counters back up fire this thing up and see what happens well right away I can feel smoother obviously we don't see any misfires counting up but I just feeling the steering wheel I can feel its nuts it's nice and smooth I don't feel that fish bite and you can see I moved it so we can see our misfire counter so right now engines happy and you can see or bee doesn't show any misfires either and if we go to our total so under misfires you can see same thing no misfires so you got a confirmed fix and there's all the spark plugs all in a row one all the way through six and they're in line so one two three four five six you can see one through four you can definitely see the VCM has done its damage to these three is the worst but four is a kind of a close second wanting to kind of suck but these two really bet and then five and six look pretty normal for the most part so that's what they look like there you go as you saw new spark plugs fix this thing for today hopefully it lives to run another day so to speak it's a direct result of the VCM variable cylinder management definitely damages the spark plugs on one through four due to fouling and it does that naturally but what can also happen is the piston rings can get realigned so that they're all in line with each other and then it creates a worse problem and if that happens this will be back in probably a thousand or two thousand miles with the same issue so hopefully that's not the problem because if that's the problem then the engine needs to be redone the Pistons need to be fixed and that's a really expensive repair and that sucks because this thing only has 90,000 miles honda was sued over this issue and they they settled and as a class-action lawsuit and there they extended the warranty for eight years from the time that the vehicle was first sold this vehicle and most other vehicles covered are now past the warranty so like this vehicle it would be all on the owner to fix it and one not going to fix it and if their way of fixing it for the most part is the first if you bring it in they're gonna replace spark plugs one through four they won't even do all six they'll do one through four send you on their way if it comes back with the same issue then they'll have to take the engine apart and fix it hopefully that's not what's going to happen on this one but only time will tell without specialized tools to to kind of dissect the cylinder bore in there this is the way to do it put new spark plugs in there and see if it comes back these look like the original spark plugs they don't look like somebody just put them in and then three is the four thousand miles later they filed up they look like they've been in there for the life of the vehicle so hopefully this thing goes another 70 or 90 thousand miles before they have to be replaced again and if that's the case well then most people will be able to live with it but it sucks if you got to pay five six seven thousand dollars to have your engine torn apart and fixed that's no fun which is the whole reason Honda got sued now I do realize that there are things out there that can cause or can tell the VCM not to turn on I wish I could do with my scan tool if I could do with the scan tool I would just shut it off and run it as a v6 and I think most people would wouldn't mind doing that but you can't do that at least not with a scan tool and not one of them on the information display Honda doesn't let you there are products out there that can fool the temperature send you know the ECT it fools the signal going back to the engine computer and tells the computer that it's running at a little bit lower temperature than it really is I'm not sold on those either because then that throws off the air fuel ratio and maybe can cause other issues so I don't think that's a true fix either so there's no good fix for this other than I wish Honda would have just not was just done away with the VCM because for the miniscule amount of fuel savings it's not worth the engine damage that these things are causing so any event if you learn anything or the video helps you out make sure to give it a thumbs up thanks for watching