HOW TO FIX P0171 & P0174 Codes + COMMON E46 VACUUM LEAKS

hey everyone welcome back to shop life in this video we're going to be talking about the most common check engine light which is for the p0 171 and zero one seven four code the code usually pops up whenever the car's computer realizes that the system is running two means when the engine is running lean what that usually means is there's more air than there is fuel for the proper ratio in order for the car to be running properly so that's why you get this check engine light and I'm gonna be showing you today the most common reasons for this check engine light to pop up what I have behind me today is an e46 it is a 2006 BMW 330 CI but like I said this is very common issue of among all cars the only difference that you might notice is things might be named a little bit differently on your engine they might be in different locations but pretty much what I'm going to be telling you there's gonna be Universal as far as most cars that's going to get started so here we have this M 54 B 30 an amazing engine but as most of you guys know this is since even though it's a 2006 it's still a 12 year old car and by now a lot of the rubber components have worn out and that is one of the first causes of the check engine light is a vacuum leak so a vacuum leak is usually easy to tell one of the main symptoms that you might have is when you're sitting at when you're sitting at idle the RPM might be jumping around a little bit so it's called a bouncing idle and if that's paired with the zero one seven one zero one seven four that usually indicates a vacuum leak so let's go over most of all the common vacuum leaks first on this motor so right off the top the actual oil cap itself so this cat has a seal on it you can see this seals pretty worn this car in particular doesn't have a check engine light for it but anyways you can still see how this seal is worn and since there is pressure in the crankcase while the engine is running that can cause a vacuum leak along with that oil cap we also have this valve cover right here so the valve cover has a gasket as you can see which attaches to the head and like I said since the crankcase is under pressure or under vacuum if a gasket is weakened really bad where the valve cover is cracked if it's made out of plastic and that can also cause a vacuum leak so continue on this side we have a secondary air pump right here if you have an older model e46 your secondary air pump might look a little different you might not have this section right here you might only have one pump right here this hose would also be different but on those models there's usually a vacuum line that runs from this valve all the way to the back of the manifold which is the intake manifold so on this one in particular we don't usually have that issue because there's an a vacuum line that runs there but that's still another option for a vacuum leak now coming on to this side this is a breather hose for the crankcase ventilation system it's also known as a CCD system which is composed of a bunch of different hoses there's one right here there's one underneath this cover there's one that goes from the actual valve which is located underneath the manifold into the dipstick tube and there's also another hose that comes from around the intake manifold right up to the top so that's another common issue a quick way to test if your CCTV system is bad or not is to have the car running put it in park to leave an idle you can have your AC and everything turned off so make sure the car is warmed up it should be idling around 600 rpm or so and while it's Eiling all you have to do is just pull off this oil cap and while it's running you should be able to feel a slight vacuum when you put your hand over it if it's really really strong that means that that CCV valve has failed or it could just be another vacuum leak from one of those hoses as well so that's a quick and easy way to check your CCV system we're moving on now this is probably the most common issue which is the intake boot so this air intake boot there's an upper and there's a lower which attaches right here and you also have this F style connector and you have one of these hoses that goes to the fuel pressure regulator which I also have a video on for this particular car so as you can see there's a vac right here and this there's another hard vacuum line that connects it to the actual regulator which is underneath the car so this can also be a very common spot for a vacuum week usually on these intake boots though you'll see a leak form right in this crevice right here formed in the boot in this crevice right in between this another common issue is if someone was doing some kind of service on your whole intake system and they did not tighten this hose clamp down or wasn't lined up properly with the mass airflow sensor then you can also have an issue with that the mass air flow sensor usually doesn't go bad that often but that can also cause issues with that system running lean condition if it's not providing the right reading for the amount of fuel that needs to go in so with mass airflow sensors it doesn't matter what kind of car you have I usually recommend sticking to the OEM manufacturer so try to get it doesn't have to be genuine but try to get our original manufacturer so for the BMW's is usually simon's video or Siemens however you want to say it so try to stick with good parts especially with any sensors on your engine you don't want to cheap out on that especially if it's in a spot where it's hard to reach we're moving on we also have that lower intake boot which is hard to see in here but I have a manifold that's already pulled off which I'll show you here shortly but we also had this diesel valve so the DISA valve is not common on most cars the BMW's most of them do have it especially of this era so the DISA valve has a flap inside it's pretty much like intake mani intake manifold actuator which just regulates some of the air that's going through the manifold to help with the whole power delivery making it smoother improving torque and whatnot so the valve itself there's an o-ring that seals it when it goes in usually that's the most common area for leaking but also another issue can be the valve itself if it is if it's lost all this pressure so it's not a design any more resistance that can also cause the zero one seven one zero one seven four and in that case there are rebuild kits that you can get for the diesel valve I just look into that I have a video that details that and I'll have that link down below now we also have this oil dipstick so like the crankcase the everything is under vacuum for the most part so the dipstick tube goes to the oil pan there's an o-ring that's on the dipstick tube where it meets the oil pan that can also cause a vacuum leak or it could just be a oil leak for that matter then you also have dipstick itself which has little or rings on it as well you can even find these kind of earrings at your local auto parts store just take one of these off take it with you and get the right size now on older model a 46 with the m54 you might also have a intake air temperature sensor so on this one the best way to tell if you have one or not is by looking at this connector for your mass airflow if you have this style connector then you don't have intake air temperature sensor on the manifold is built into the mass airflow if you have the older style you're gonna have an intake air temperature sensor on the manifold which I'll show you here shortly now like I said earlier the reason for the check engine light is usually when there's more air than there is fuel for the proper ratio so if you have a weak fuel pump that can also cause you know the car to have a lean condition so your car might run properly and everything but if the fuel pump is not providing enough fuel then you're gonna have the system running wean the fuel pumps are usually a lot more expensive and on some cars that are kind of harder to get to so I would try to save that towards the end and by now if you're getting this check engine light chances are the cars at least 5-10 years old and most of those rubber components are worn so you probably needed to replace them anyways so doesn't hurt to do all the vacuum components all at once it just makes it easier for you to just knock all of it out at once then having to keep chasing it down so I have a manifold that's already pulled off let me show you some of the things I was talking about earlier alright so this is the intake manifold which is attached right here and this is pretty this is a very similar one to that but it is off of an older style and 54 which does have that intake air temperature sensor that I was talking about so there is a whole ring on that sensor that when you pull this tab you should be able to lift it out and the o-ring comes out from in there so that can cause a vacuum legal this is where the DISA valve goes and like I said it was owing on here that can cause vacuum weeks now we also have this brake booster hose so this hole is goes directly to your brake booster which is located that hose goes directly to the brake booster which is located right here so the brake booster hose and you can see this one's a little squished in but for the most part they don't usually leak that bad even the valve that's about to connect to they usually don't leak but like I said there there's always that one car that has something that nobody else does so if you're having troubles that can be an issue another cut another uncommon issue is the brake booster itself so if you're sitting in your car at idle and which are foot off the brake if you hear some kind of hissing noise inside the cabin that usually means that the internal diaphragm on the brake booster has failed which will require which will require you to replace the entire brake booster since the internal diaphragms are not serviceable that is a bit kind of a big job since you do have to remove all of the master cylinder and all that but that's like I say there's a pretty uncommon issue and you should be able to hear it right away now back at the manifold so here is that brake booster hose that we were talking about here's the top vacuum line that goes to that upper air intake boot then we also have this line that goes to the fuel pressure regulator and then you can also see the actual brake booster line that keeps going to the bottom of the manifold is right here the lower intake boot attaches to the throttle body as well as the idle control valve right here the idle control valve also has a grommet that attaches to the intake manifold which is this silver silver gray drama right here those usually rarely fail but if you're pulling off the file control valve to clean it or anything might as well replace that same thing with the throttle body it has an o-ring on the backside of it we're attached to the manifold so if you're taking it off to clean it which I highly recommend might as well go ahead and replace that now here's a CCB that I was talking about earlier so this is the actual oil separator valve and there's quite a few hoses that attach to it so one that's missing right here goes from the bottom of the valve to the oil dipstick tube so that's the one that's usually the most common as far as leaking even with it's leaking oil or whatnot so that's one thing that you want to check out then we have this one that goes to the valve cover and this is also a very brittle plastic connection so sometimes they do tend to break even when you're just doing like a valve cover gasket service on the valve itself there is a vacuum port which should be capped off but if it's if that cap is worn out chances are the CCP valve itself it's time to get it replaced but if you just want to replace that for now you can try doing that now coming to the back of the manifold so this is the part where you really can't see it let see how the manifold taking off here is one of the vacuum switches so there are vacuum lines that go all the way across there's a one-way valve right here you usually have these two sections capped off and on some of the 46s you will have another vacuum container down here which will have a vacuum line running from the manifold to the container and from the container into the cabin so you want to check all of those out as well now one of the most uncommon ones are the intake manifold gaskets they usually don't leak unless someone's messed with it and if you're pulling off the manifold if you're going through all that trouble might as well replace that while you have it off there about 30 to 40 bucks go ahead and replace those and that's pretty straightforward as you can see it just comes right off so that pretty much covers most of all the vacuum leaks the common ones at least and hopefully that helps do fix your check engine light I'll have a bunch of videos linked down below that goes over most of those repairs and also some of the products that you can buy so that way you can go ahead and do the repair if you need to but like I said if you are chasing down any of these vacuum leaks chances are most of those vacuum lines are done so might as well just replace as many as you can and as a matter what kind of car you have just try to replace them all vacuum lines are not that expensive if they are molded then yes they might be a little bit more but if you can find the part online it's usually a little bit cheaper anyways thanks for watching if you guys have any questions feel free to comment down below or if you guys want me to do another one of these videos with more common check engine light codes or whatnot flow for you to list any codes that you might want me to cover and I'll try to do that on my next one thank you guys for watching

Channel: ShopLifeTV

Views: 395,070

Rating: 4.8688002 out of 5

Keywords: BMW, bimmer, engine codes, p0171, p0174, tutorial, diy, cars, car, diagnose, vacuum leak, code p0171, how to fix code p0171, how to fix code p0174, COMMON E46 VACUUM LEAKS, bmw e46 common vacuum leaks, common vacuum leaks, bmw common vacuum leaks

Id: QiqUAF0zxCk

Length: 12min 38sec (758 seconds)

Published: Thu Aug 16 2018