Mercedes-Benz E500 No Start, No Communication with PCM

hey guys scanner Danner here today I'm in my classroom at Roosevelt Technical College and I do not have a class today but this is the perfect place to film with you guys and what we're doing today is working on a 2004 mercedes-benz e500 the symptoms of the car from the customer he stated that he replaced his starter and the vehicle still doesn't crank and so when I got here I noticed that I couldn't even turn the key so I was messing around with the key fob and checking the batteries in it and then I called the customer or texted him to see exactly what was going on let me give you a heads up on what he said he says I changed starter because I was driving the car the other day and when I turned it off it never started back up okay so he was driving the car shut it off no issues wouldn't restart then he replaced the starter and after he replaced the starter he says I then had the no key turning and no power so what I experienced I put the key in could not turn it the reason that there was plastic and tape on the window is because he couldn't get his window up because he couldn't turn the key and so the window it wasn't broken into I was thinking anti-theft issues again I'm worried about the key fob so I asked him about the key and he tried both keys and nothing so I I'm doing this a little bit in hindsight guys I turned the camera on where I found an issue and I'm going to bring you up to speed but my concerns with this were within the anti-theft system the key fob and all of that and just was messing around with it it started to work and so now I can turn the key and I push the car in the room and it doesn't crank and that's kind of where we are so let me get you up to speed with the system and and what we're doing take you right here onto the scan tool I already have the vehicle identified and I want to show you that we have an O column with our engine computer oh the other thing too I have the fan actually unplugged right now let me turn the key on - all right key is on one other thing I'm gonna plug this cooling fan back in so you can hear it it's super loud too these are my symptoms ready for takeoff listen to that saying bad all right so I'm going to unplug the fan so I can talk to you okay so the key is on the cooling fan running all the time is not a good symptom that's an indication of something going on with the engine computer and you guys can see here we have a no communication with it so my next step I really wanted to do an all code scan on this but I cannot I'm only given the option to do them individually and so I started checking a few of them and I'll let you see the anti-lock brake one because I know I was able to talk to that I'm not going to go through every module here and see if we can communicate we're going to focus on this engine computer and why it's not talking so go to codes so we have an under voltage voltage supply this is in the ABS module system fault test ECU so not sure what that means in particular I didn't look it up and then the bottom one says engine control module control unit so that's kind of telling me maybe a communication issue that the ECM is offline each time I change each time I go into a module and come out it keeps telling me to cycle the key Ostend and then turn the key back onto the keys off it's just a long drawn-out process I'm not actually going to show you any other module on this there's some communication area network faults in some of the other ones that talked about can lo I guess I can show you that but I don't think that's the direction we're going here the one I was looking at is this system diagnosis codes on this one knowledge base configuration incomplete stuff I don't know what it means I haven't looked it up synchronization of the DTC memory cannot be ensured can communication of control unit es a passenger is in the single wire mode so canvas low interior can bus short-circuiting can lines so some interesting faults there again it would be nice if I could read all of these get you all the codes at once this is just too long of a process so I can talk to other modules on the network one other piece that I just did a real quick check on and I understand that this isn't always necessary if I can talk to everything else on the network then I really don't need to look at the network lines but let me let me do that for you guys real quick we'll get set up in here on the network I'll show you what I did just using my little lion spy tool by AES and you guys are it's all mine and Tommy Wolf's Volkswagen video where we had an issue with the TCM you saw this tool so I'm hooked in to Mike and network let you guys see these signals all right I'm going to my scope multimeter lab scope this should already be set up so your your yellow trace is going from 2.4 to 3.7 volts green trace 1.1 to 2.5 you know theory says one and a half to two and a half four can low and two-and-a-half to three-and-a-half or can high but there are some tolerances there are some differences from what I'm seeing on these networks let me get you a little bit more zoomed in and I'll set a trigger for you guys you can see it a little bit more consistently here alright so some pretty clean looking Network signals I think nothing that I'm going to do anything there with and I'm not going to go any further as far as the can Network goes I'm going to attack this no column to this ECM just like I would any other system I can't communicate with it I can communicate with other modules on the network so we really don't have to worry about the network and so my next step is to look at a five volt reference circuit and see if I have a 5 volt ref so let me show you that so again I'm filming in hindsight here guys and I just pulled these covers off before I turn the cameras on my next step was to find a sensor that used a 5 volt rest and I use the wiring diagram and found there is a pressure sensor right here in this location you see I have it back probed already and the wiring diagram is actually a little bit wrong on this as far as the color it calls this a red black for the reference here let me show you that real quick we have a it says red gray a brown gray and a red black but look at this connector there is a red gray there there is a brown with a gray this one and then a pink black so really looking at this sensor I can see that there is a vacuum hose going to it and it's a three wire sensor so it's definitely a pressure sensor by the way is it my classroom suite you guys are interested in our program here Rosedale Tech I'll put a some info in this video either some links or an icon that you guys can click on I can do that this little fact I'll do that there will be a exclamation point up here in the corner if you click on that it'll take you right to our website the school's website Rosedale tech dork you can check out our programs I am in my classroom I love this place I've been here this September will be 17 years all right checking a standard three wire pressure sensor five hole refs signal on the ground this is universal stuff this applies to every system out there this is not unique to any one car I'm just going to check the three pins this is what I did before I have the diagram will check all three pins I'm not stuffing this t pin in I'm just touching gently 0.34 point 0 1 & 0 so the one that's my reference wire let's back probe it now is this pink and black diagram says red black but it's point zero 1 of a volt so we are missing a 5 volt ref and so what we'll do then the missing 5 volt rest is we worry about shorted sensors we also worry about powers and grounds I know some of you are thinking from that Volkswagen video in particular check the fuses I'm with you there that's what we need to do let's make sure that our computer fuses are good and then we'll go from there all right so I already map the diagram out there's one main fuse here let's fuse number 42 number 42 and that's left end of the - okay and then one other one this one that's hot all the time there's a relay use number 43 in the left rear of the engine compartment so number 43 number 43 in the engine and this one's - okay - fuses this one is actually powered by a relay so the relays got two close powers this views up and then everything I have in yellow Oh two heaters powered by that a bunch of solenoids or powered ignition coils injectors off of this circuit something relay it says here but we'll connect that fuse for power this fuse would be dead if this relay doesn't close if the relay closes both sides of that fuse will be hot so I'll show you that next if use 42 in the - she's 43 under the hood and as you can see we see numbers on here very clearly we're going to check both sides of this fuse all right but the fact that the fuse is even lit on one sides telling me that that relays at least turning on so that fuse is good next one is inside so which one is fuse 42 in here nice of sadie's to give us a little sheet here it's kind of nice so you see our fuse box layout see the two bolts tribes picture there's your there's the two bolts right there fuse number 42 F 0 4 2 is bottom right that is not guy right there alright put this back so fuse 42 7 and 1/2 amp fuse is hot on both sides so our powers are good so now we can take a moment and give some crap to all of you who told me and Tommy to check the fuses ok the fuses are good now what do you do that's why we went the direction we did in fact on Tommy's Volkswagen you could have checked the fuses they were all good that fuse was located was fuse 29 was located in fuse 30 so you guys that don't know what I'm talking about right now I'm referring to a Volkswagen video that Tommy wolf and I did a positively Diagnostics and the way the video turned out was great and I'm it doesn't matter that well I got a lot of grief over the fuse but the thing about that fuse was it was relocated into a spot that had a hot pin and a missing pin so what happens when you plug it in say this fingers the hot pin and nothing you know the second pin is missing but you plug the fuse into that this one's going to show hot on the back of the fuse and so is this one so both pins so in other words the fuse would have tested good and without a layout of that fuse box which there wasn't one you wouldn't know that that fuse was relocated unless you were looking very closely so anyway fuses are good now what next step for me no 5 volt ref good fuses my let's check these powers at the computer itself it's right here in the box easy to get to that's why I'm going this direction so let me show you what I found to locate this connector I really just went with some wire sequencing and it's pretty easy to locate it because of all of these brown wires no brown black brown green brown grey brown brown brown brown right whole bunch of brown wires in here so let's see if we can locate that go ahead blue and red violet red blue and red violet are the ones we're going after see this connector here and then look at all the brown wires you have there it was a 9 pin connector surprising that these aren't insulated I mean you can literally see the back sides of the pins so there's my red with a violet real tough to see the violet color on that red there is a violet tracer and then the red red with a blue is that guide heavier wire right next to it so let's do that one first so there you go 12 point two four so that is again the key powered one that's the one that comes from the relay and that be the underhood fuse box now I'll pull this I'll pull this fuse and let you guys see that we will lose power when I pull this fuse away okay so that is my relay circuit power feed and then the one that's hot all the time is this red with a violet tracer okay and damn three volts three volts on a main feed got a voltage drop on that wire no doubt about it so that fuses inside of the vehicle and it comes out to this location and you see the main harness right here so what I want to start doing is I want to start wiggling that harness and while I'm watching my voltmeter and let's see what we can come up with here before we continue here guys this is the point where I stopped what I was doing turn the cameras on so I've taken you as far as what I've done off-camera so no comm let's review that real quick so we have a no communication with the engine computer I can communicate with the other modules on the network I didn't pull up a network diagram I didn't study the network it's not important right now you know we had some some stuff on the VW video with the Gateway and how it was wired and none of that's relevant for this in my opinion ECM no communication doesn't explain why the key wouldn't work we have an issue there potentially separate from this it is working now I'm going after what I know which is the engi computers not talking it's why the cooling fans running all the time it's a default I believe tech fuses they were good it's like the power feeds at the computer because of a low reference voltage circuit okay we use the map sensor or a pressure sensor might be an easier pressure sensor I may not even have an EGR valve it is a pressure sensor for something most likely a map sensor 5 RF is missing we could start on plug in sensors and doing whatever but it was easier to go to the computer be given its location right up top nice and easy to get to two main feeds there you go three point six volts and that's fluctuating as I'm talking I'll probably have in the Edit you guys will be looking at that the whole time so kind of strange that that's moving around let's find where this voltage drop is and we'll at least fix this part of the car I have a feeling we're gonna have other issues given the customer replaced the starter and it's got some weird warning lights on about battery and things like that which might be related that's why I want to fix this first so let's let's see if we can find this broken wire let me put this battery tender back on to you guys may have just seen a little voltage increase there when I put that tender on four volts is not good is it got some movement but it's moving around on its own - and that goes down this way crazy that this computer box is just loose in here I need to disconnect this for a second I think it seems like somebody maybe had this out I'm just trying to follow the harness where does this harness go two-point-seven what I want to do is jump power to that so you guys the reaction get our reference voltage back something that I've done already so I guess I lied to you I did do one more thing which is I did jump power to this and I did get my reference voltage back but I still couldn't communicate with the ECM so I can show you guys that but we're still going to be attacking this first because of the no column I may not have had the key cycled when I did this too so see the other thing too let me plug this fan back in just thing still Wiggin out on us see if it is oh yeah that's going to be super noisy so I'm not going to plug that in I need a power feed I can jump to we use this big fat power feed wire how long what it's for but I want to use it here the electronic throttle body doing its thing let's plug this cooling fan back in now see what that does yep fan is not running take this power feet away and there goes our cooling fan [Music] engine computer now has power and this stuff out of the way if you guys are reading on my five volt reference circuit now sigh volts baby so missing power feed to the computer losing my reference voltage watch I'll take this away again there's your reference is gone so it's not not a shorted reference in this case all right so now can we communicate with the scan tool does the car start more importantly alright to go into my home screen scanner we'll go to the engine may want me to turn the key off first wouldn't talk to me any other time I tried it even with this circuit jumped but I didn't turn the key off and wait after you know kind of powering up the computer at a time the timing was off half the computers alive half of its not hey I didn't get this far before go to codes no codes present this Carson starts I'm not sure what this ESP is says service ESP but I did notice the front struts look like they were replaced it looks like a position sensor to me and that looks like a pneumatic line that's supposed to go to a strut that yeah there's a solenoid probably it's now missing these look like they've been replaced recently somebody got rid of the electronic suspension on this is my guess the cool part here is I have communication now does the car start sweet men to all we have to do now guys is we got to fix this messed up wire between the fuse box in here and out there and if I have to I have to I'll run a new wire I don't want to but if I have to I will and honestly the reason I don't like to run new wires is where I anytime I found wires that were damaged not any time but a good portion at a time you find a wire that's damaged you find other wires that are damaged in the same location so I like to try to find where the wire is damaged and really seriously this would have been cool to film right from the get-go I just got a little bit nervous because of the key issue and doing homework on the computer and having the cameras on is a little bit difficult sometimes I apologize out and bring you right from the get-go but we're not working hard this is the mercedes-benz unfamiliar car to me I don't work on many European cars but its fundamentals right once you understand your fundamentals like the 5 volt reference circuit how important is it to know about your five-hole trap picking your five-hole trap line put me in the exact direction I needed to be in right focused on the computer powers and grounds check the main fuses they're good check the main powers at the computer they're not that's where we are it's pretty simple isn't it so for you guys that need more that are maybe on this channel for the first time this would be chapter 9 material which is I call my 5 volt reference circuit a bunch of videos on the reference circuit and you'll see those related videos case studies linked up with that playlist on right here on this channel so I'm glad you're here thanks for being here now let's find this broken wire oh let's do something here take a look real quick guys at the the can network again and there's really no difference in the way that that looks before and after like that TCM issue on that Volkswagen Tommy and I did you know where the TCM wasn't communicating from a bad power feed on one of the lines very very similar to this and how distorted it was I just kind of look at that for a minute and what I'll do is I'll unplug my jumper wire now I'll let you guys look at it [Music] let me unplug this cooling fan we all hate it if I don't so no real difference in that network that I can see just an observation the computer on the network that is missing a power feed can distort the network depending on where it is located in the network all stuff we covered in that Volkswagen video but what we're going to do now guys is we're going to go back to our power feed wire which is this guy 2 volts on that where is my wire broke I'm going to do a quick visual underneath the - guys if I see something I'll bring it with me I just want to look at the back of this fuse box going to disconnect this [Applause] [Music] see anything down there any critters dude I hate to say it but this might be one where I'm running a new wire because I am not killing this car apart just to prove a point I'm not doing it and I get lucky and pulling this and this wire breaks it's got to go into the dash right there but I don't see without moving this fuse box I can't tell we know it goes in that way but where does it come out here first what a pain in the butt see with the computer out there's a good example that it's reading 8 volts that's a good example of why you want to do loaded circuit voltage job testing you see with the computer removed by now I have 8 volts on this circuit because the computer is the load still be enough in fact this won't even light my test light watch my test light will pull it straight to ground right there BAM zero volts with the test light we should use that as our guide wires broken somewhere people and looking at the diagram you see there's no no dotted lines in here so it doesn't feed any other circuit it just feeds just feeds my engine computer mentals pretty good about putting dotted lines on fuses and circuits that power other things so I couldn't pretty much trust that I could pull a power distribution diagram if I was concerned but I'm not hot all the time where is this wire broken oh we got some critters that were living down here yes sir oh yeah we got a nest right here part of this fuse box too I hate hate the thought of rotting in a wire see any damage there moving around isn't it test light in there zero volts now that bulb lights a business now we're reading eleven I've got to put me right there we're reading twelve volts now on the volt meter watch what it does when I pull my test light on it crazy isn't it voltage drops man good lesson on job testing you guys can't see my voltmeter here hang on let me do that again this stupid meter keeps cutting off on me and look eight volts zero eight all right it was 12 a second ago after pulling on this harness [Music] good lesson on voltage drops this I knew the configuration of this harness and where this actually goes I'll just put my volt meter off so you guys are going to see that for a minute up on this car apart anything easy to get to on this alright I'm hoping hoping what is that no stupid oh come on we just lost power in the building we have backup generators come on generator there it is just trying to see where this harness runs it does power another circuit it looks like [Applause] [Music] [Applause] I hate to do it guys I'm really really leaning towards it otherwise I'm going to be here all freakin day and I'm not doing it I'm not it definitely comes out of here I think I'm concerned about the Hornets down below I see animals but I can't it's under the master so under this whole box that have to come out another module in there this blocks [Applause] [Applause] so what does not come out unless you take the wipers apart sit in the wiper arm does go into the desk right there how many critters in here and harness goes right into the dash so there's my issue under the dash that seems so unlikely it's not it doesn't go down where I thought it went that way it goes right into the dash and I do not see any damage in here let's take a look I take that bottom cover off you know it actually could be the fuse itself too and I never even considered that have a voltage drop right at the back side of the fuse like it's good on the front side but bad on the back side so let's do this let me get you guys rigged up with the test light now I have power what did I do that's the one I was missing power on all I did was bolt the fuse box back up moved the fuse box bolted it back up all right so I touched something my guess is it might actually be the fuse itself you guys watch the test light I'm gonna wiggle this fuse make this against abuse none of them hey I checked the fuse what I'm just going to push on this watch the light go out I just saw a light go out do feel like changing right there right there so yep right there none of them so by me moving that fuse box all right so where's the issue at now is it moisture intrusion into this fuse box oh my goodness yeah look at that excuse it's absolutely absolutely moisture intrusion you know where did it come from windshield maybe door seal who knows that's it look at that yeah we're gonna cross these on there there's your voltage drop so what I need to do is replace this fuse just cuz you know I could clean it up put it back in maybe try to tighten those terminals up tell him he needs to replace this fuse box all right so if you remember I mentioned on the back of that fuse box that there was another wire there look how bad that is inside too I pull this back out so I think that could potentially have been an issue with the yacht with the key so um when he said but he couldn't turn the key and I couldn't either at first until I messed around with it and I was checking fuses that's what it was - because I came down and I was checking fuses for the ECM and then I think after I did that was when I was able to turn the keys and so yeah that makes sense again a good lesson on why you don't want to run another wire and why I was so hesitant to do so see there's two wires here that was my concern was these - these are hard all the time you know you could rig this box I mean it definitely got moisture in it from something from what I don't know but is heavily corroded pins in multiple locations all right so I'm going to tell him I'm not messing with this fuse box he needs to replace this box but for now we can at least get a new fuse in here these pins are really corroded not really a whole lot I'm going to do with that let me restate that there's not really a whole lot I want to do with this all right so we're going to put that fuse back in go back up front yeah our test lights lit legal just around the coast light staying lit I'll tell him this owner what to do [Music] start to melt a little bit - from the corrosion resistance equals heat guys ah look at that fused totally came apart on me that's from heat - right there so it's got more than one circuit that's being affected that's probably why they ended up changing their suspension system - which is stupid way to go get another fuse heat resistance equals Heat alright this light is lit so remember your 5 volt reference circuit guys one of the best tests that you can use for no column on an ECM unplug one of your sensors back probe one of your sensors that uses that reference circuit you got no five-hole trap that's where you need to stay don't deviate from it fix your reference problem you'll fix the car it's exactly what we did so good enough for now we're going to fuse test lights stay and lit under the hood again the test lights adding a load better than the voltmeter in this application at least what I'm doing right now because I have the computer unplugged let's put everything back together gotta be careful with this hot feedback here they don't hit this off of this wiper arm should have the battery disconnected doing this but I didn't I'll bet you if we would have poured a power distribution diagram maybe I'll do that before we end this we pull a power distribution diagram what we're going to probably find is that that other wire that was tied into this one at the fuse box probably goes to the keyless entry system that's my guess and that would be why the key wouldn't come out or not come out why the key wouldn't turn at all this is progressive getting these out you got to start at one end move your way down [Applause] [Music] [Applause] I guess the non-weather pack connectors for the computer I guess maybe they you know this box is weather-sealed is my guess I mean the it looks like the main sensor components are using a weather seal but like this main powers and grounds I mean it's a wide open connector with no insulation on the back I'm I can see the bare pans on the backside just kind of interesting the circuit and how they designed it sweet alright does this go around Oh better get my screws back in good example guys of why I like to film live there's no way that I could have duplicated that once you move that fuse then you make good contact and then you've never able to show it again I apologize I didn't get you guys in with me on the initial when I first started would have been better but at least I was able to show you the main pieces of it cool alright does the car start alright that I've plugged my cooling fan back in no I did not super super important piece right there definitely don't want this guy to be taking his car away and then having it overheat on the road will be really bad plug this pressure sensor back in was to clear our heart clear our fart yes clear our fault codes because now the computers alive I've got this pressure sensor unplugged as a cooling fan unplugged okay I'm gonna pull this car out so I was going to plug my premium channel but I don't need to do that that's where this video is going but I can't plug my website that is scanner Danner com don't forget about using the playlists that I have on my scanner dander premium tab on my website so you guys that are maybe new to this channel you can follow all of the playlists of all of my chapters in my book and be part of my classroom online already but I've started gathering the data and just moving it over to my website not the videos the videos are still hosted on YouTube you still need to be subscribed to YouTube the paid channel to watch them you can click on the links but all it is is a little movie player' that takes you right to YouTube but that playlist is awesome I'm telling you that what I've done again is I've put my lectures page for page from my book and then I put related videos next to it some of those related videos are on the premium channel some of them are on the on the free Channel and it's just a great guide to to self-study that subject so so we're talking about the 5 volt reference circuit for example for this one that would be chapter 9 so you'll see chapter 9 lectures and then next to those lectures you're going to see case studies where I've dealt with a 5 volt reference problem there's probably four or five or six videos there where I'm dealing with reference circuit problems so again want to remind you guys to go to my website and use that premium tab scanner to enter premium tab the drop down menus use the playlist still working on them at the time that this is being recorded I have the first six chapters done working on them all the time so keep your eye on the tab if you're ahead of me on my premium channel tab on my website you can follow those playlist again right here on YouTube they're just not as well organized I don't have the ability to configure everything the way that I want to have it to make it flow very nice for you guys on on on following this channel so again thank you so much for being here love you guys man you guys mean the world to me I've said that many times changing my life so my loyalty certainly is to you guys I want to keep you guys here and this was another good one to learn from voltage problem reference problem no communication how do you handle it good car hey thanks guys I'll see you next time [Music] how about closer on congas come visit us Rose Delta Korg

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Views: 565,423

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Keywords: scannerdanner, how to, check engine light repair, automotive electronics, RTC, Rosedale Technical College, scannerdanner.com training, online auto mechanic training, auto technician training on-line, become a mechanic on-line training, Mercedes-Benz, E500, no start, no communication, no spark, no injector pulse, no fuel pressure, fuel pump doesn't run, cooling fan runs all the time, no check engine light, CAN buss, network diagnostics, CAN

Id: qmvfvJs01Eo

Length: 51min 22sec (3082 seconds)

Published: Wed May 03 2017