2012 VW Jetta No Communication with TCM U0101 (part 1)
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- เผยแพร่เมื่อ 20 เม.ย. 2017
- Vehicle is stuck in park, check engine light is on and there is no communication with the transmission control module. In this video we will be troubleshooting the CAN network using a lab scope. In Part 2 • 2012 VW Jetta No Commu... we repair this vehicle and are surprised by what we find.
Here is the link to Tommy's TH-cam channel
Positive Lead Diagnostics / @positiveleaddiagnostics
Tools used
- AES LineSPI (SMART BOB)
www.aeswave.com/cart.php?m=af...
- Test Drive Test Leads for the Snap-on VERUS
www.aeswave.com/cart.php?m=af...
- VCDS® with HEX-NET® Pro
www.aeswave.com/cart.php?m=af...
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Great job guys! you showed the way many of us have to learn these systems. This just shows the lack of info that the engineers don't share with us as real-world techs.
I think this is one of the best vids yet. While watching I'm thinking this is gonna be complicated then knowing about the can bus resistance and thinking to check powers and grounds what else? It cant be that simple. So good watching you guys bounce ideas of each other and take the diagnosis a step further trying to understand how the system functions as these systems are constantly changing. Judging by the resistance difference at the tcm compared to the aldl connector it seems there may be separate can bus lines for different systems but all terminating at the gateway? There is some awesome talent now available through you tube with yourself Tommy Ivan Eric O and now Keith coming on board. To be able to learn and apply these techniques like this is awesome. Respect.
So great to see such wonderful diagnosis with manuals, thanks so much to you both.
Got it Mr.SD and another automotive (positive lead diagnostic) channel in my list.
Exactly what I have been struggling with on my 2011 GMC Duramax in regards to Can, Serial networks ,this video is very helpful and I am glad I invested in the actual service manuals when I purchased this truck ,wiring diagrams ,explanations of networks and the other modules involved with any other module .Watching you guys really helped me understand what it is I am actually looking for !! Still need to absorb how to utilize measurements of terminating resistors with the use of DMM
Great job guys
Ya know that stuff shld come free when you purchase a vehicle! It's BS having to pay almost $100 just to get your hands on info about a vehicle you OWN! It took me over a mt to find PART OF a service manual online thx 2 someone generous enough to post a download link. Def no thx 2 the Acura dealership who wouldn't even email me a wiring diagram & instead put me on "hold" (well said they were transferring me but hung up on me instead) & other times I called wouldn't do anything except tell me to get my car towed to the dealership! I'm unemployed at the moment so I couldn't afford to pay for a service manual much less pay the dealership to repair what I was able to fix for $5 once I accessed the info that's readily available to their mechanics!
VW, all the Euro's and especially Land Rover NEVER give enough info. They only give the bare minimum. In the case of Land Rover they always refer to their OEM scanner ( testbook) for tests, as vague as "consult the testbook". it's refreshing to see knowledgeable people such as you two still struggle and struggle with " I think it might be the TCM" Your videos are always the best because they are real world, you have a humbleness and you don't candy coat it like so many do as they try to make fixes look so easy.
Always excited when you, SMA or Ivan upload a new video. Whenever you get the opportunity, I'd be interested to see you go over push button ignition systems on newer vehicles. I managed to find a wiring diagram of my parents' 2015 Honda Fit starting system and was baffled by its complexity. There's nothing wrong with the car, but I was interested in seeing how these newer ignition systems work. Thanks in advance!
Working at a indy euro shop the hex cable and vcds is literally priceless
I liked the different camera angles. You did good at asking questions. That kept me on track and interested. Not having information is so aggravating. Great team effort guys! I'm subscribed to Tom. He's doing great work.
From the research I have done, the termination resistors are designed to stop ringing in the data line - sort of echoes that would make communication impossible.
Think of the ringing on an ignition coil that has 'back EMF' after the spark burn time has completed - you get that wiggle that is an indication that there is reserve left in the coil, ensuring the coil is in good condition. So the resistors stop that ringing that would echo back and forth over the BUS line and seriously mess up the actual communication. Testing the resistors is one of the basic tests of the BUS line.
More of us Lecturer/Tech/TH-cam creators are making it easier to diagnose problematic vehicles. It is the best way to share the knowledge we have gained over the years.I have been a Tech for 34 years, a Lecturer for 14 and TH-cam creator for almost 2. (Sorry for the plug....)
Great to see you guys working together.
Keep up the good work!!
I would say the best way thinking about the Gateway in a Volkswagen network is comparing it to an interpreter. The main work the gateway has is making it possible for different types of Can talking with each other. If lets say the door wants some information from the engine it can not ask the ecu directly due to not using the same type of network, the door uses a low speed can called convenience can. Therefore you have a gateway that translate and sets priority.
A good tip for using Volkswagen style diagrams is using them in the computer and use CTRL+f to find what you are looking after (for example tcm just open the correct diagram and write j217).
Sorry for not writing good in English and making this understandable.
Thanks for the info!
Great video, thank you and I hope you continuing sharing your knowledge with us
god bless you and your family too
scanneryoda,keep teaching excellence. wonderful to see a former student excel....your the best my brother.
I've long thought all cars should have a full wiring diagram or at least a network diagram printed under the bonnet (hood, I'm British). I'm sure a lot of people (myself included) are liking these network communication case studies. great stuff chaps.
it's adorable when Tommy comes out with Dannerisms like 'it won't get out of its own way'. :)
Most of the drivers don't even know how to change a wheel or to ceck the oil. :)
Imagine how they look at a diagram? :)))
But I woul love to see this on every car !
Great video like always! I've been teaching lots of network diagnostics to my students. Really nice to have some backup to confirm my teaching. I recently learned that on a 2015 Jeep Wrangler, the network is very similar to this VW, in that you must back probe the network to see past the gateway module. I tried pins 6 and 14 with the breakout box just as you guys did, but found these pins were for scan tool only.
nice!
Awesome video bro... this would have had me scratching my head for a while man thank you for sharing this knowledge and know how ....
Just got done watching this one, love it. My 2009 jeep wrangler pin 14 and 6 pin of the diag connector go directly into the gateway/
totally Intergrated power module. Same thing, measures out at 60 ohms but no signal. I figured it was just used for communication with the scanner too. So I moved it to the power train control module and got the signals. I have also been burnrt too by the fuse deal that tommy ran into as well. Great catch Tommy! Here is what caught my ear!!!!!!!!. How many modules have just one power feed input???? From what I have noticed there always seems to be a keep alive power feed and a key on feed. That is the lesson I learned here. Paul and Tommy keep it coming, It takes real guts to stick your neck out. Thank you again. Scott Shoellhorn
Awesome.Paul.I just had read an article a week ago in Motor Age from Eric Ziegler about Can network and diagnosis and here it is, more from you. Thanks for the video.
Awesome video! First of all you and Tommy doing a diagnosis together 👌 I would love to see more on network troubleshooting. This gets harder every day in modern vehicles. Thanks guys!
Thanks Dylan! As I learn more about these, I most certainly will.
I don't think the network diagnostics are as voodoo as people make them out to be. And no matter which way you spin it, you are potentially going to be ripping a car apart to access all the modules on a crashed network, so you can unplug them one at a time.
I think everyone is looking for a short cut, and I'm just not seeing it.
Think you're right Paul. There is no shortcut 😞
Always excited when you doing trouble shooting I learn alot from you Paul. Thanks to you
love how you guys kept it real
Great work guys! BTW K line is the communication line:
Kommunikation in german it was present for comm with the scantool, long before the can network
Thanks guys that was a excellent video!! Cant wait for more from you two..
GREAT VID GUYS, RESPECTED, REAL WORLD TIME REPAIR ON A CUSTOMER VEHICLE, LIKE THE HONESTY BOUT THE TRUE ISSUES ONE RUNS INTO
great job Tom and Paul thanks for share this case is realy interesting.
I work for audi 8 years now and I completely agree with the current flow chart being trash, I suffer the VAG stuff daily but it becomes familiar in a way. Really impressed with danner I like the raw side job approach to these videos because they are real life situations. Thanks for sharing this knowledge I will be using it to become better
Thanks so much stephen marshall!
Bro your cap is splitting with all that brainpower!! Love your work.
haha thanks
I went to a training night on these more modern can bus com systems when they first came to Oz. We were told the terminating resistors were there to take out the reflection of the can signals at the end like waves in a wave pool, similar to trying to absorb resonant frequency to stop it generating its own signal.
Awesome!! I think this would help so much for what I'm working on right, love that new tool that reads the data link
Brilliant work!best video yet thanks
great video danner...i just got my otc box today u just answered a ton of questions I had wow thank u
great video guys a look inside side VW way of doing things. my very limited understanding of the gateway is preventing me from having a hard opinion either way I'm leaning towards not caring for it only because I don't see any advantage to it yet great video
Danner, I'm so freaking jealous of your Hex+Net.
So glad you guys made this video because there is so little out there to help guys in the field understand this subject area.
Thank you for taking the time to tackle a subject that everyone seems to be still confused about at times!
Both of your guy's channels are top-notch, wish you the best!
Working through it with you guys is the plan. Thanks!
ScannerDanner, well I cannot thank you enough for all the lectures and in depth analysis you put into your content.
Filming your work has got to be difficult and time consuming. Further, you still have to fix the car!
Having your experience and knowledge outlined in such a way that truly teaches critical fundementals is invaluable! Keep up the good work you guys, you deserve success for all that you are doing!
Awesome video, love the variety!
Very good video i have the exact problem with a 2007 touareg that i purchase from copart ,now i will go and do some mesurement .
Scanner
Paul, What a superb video this is! (And I love the background bird song - sounds like there’s an aviary at the garage.). I’ve gone right back to the time I joined SD Premium and I’m catching up on some of the videos I haven’t seen yet. It’s fascinating to see how much you’ve learned about CAN since this video - how much more knowledgeable you now are on CAN.. You’ve answered a few of the questions rattling round in my head eg why do you see a different CAN signal at the DTC as opposed to at the TCM. And all the questions you and Tommy ask each other in this video were going through my head at the same time, so it felt as if I was right there with you.
This is an excellent introduction to CAN networks. You should tag/label it as such. It’s also interesting, because I thought you’d see the identical network activity wherever you back-probed or connected (eh pins 6 and 14) - this video shows that’s not the case. (Maybe it is on a certain type of network topology, but this shows you can’t take it for granted.)
You’ve never made a bad video yet, Paul, but this one is Pure gold. Looking forwards to watching Part 2 now. You must be really proud to see how one of your students has become a master tech. How about teaming up with Tommy again for another video?
Great video. Nice too see some VW stuff. Also nice camera work and multi angles! Will check out his channel too!
Also you put out great video scannerdanner the audi you were speaking about with a faulty engine mount I've actually seen that a few times it was pretty easy for our shop to diagnose then again we are a Volkswagen shop / Audi
Great video thanks
I made similar mistake a few years ago while trying to demo a scope checking can signal from the obd socket on a VW and was not getting any signal and only after checking wiring like you did figured it out
Up to about 2004 VAG group did not have a CAN in the diagnostic socket and they just used k line to talk to all ecus on the vehicle
And on the later ones they used CAN to talk to all ECUs but they still used Kline as well for engine
As if the gateway is gone down completely you won't be able to talk to any ECUs except for engine as you can still connect to this through Kline
Love the way the diagnose went, felt like I went back in time to the shop facing the problems, loosing signals, trying to find where to look, freaking diagrams and all.
Awesome information. Appreciate your willingness to "learn the tool" on video as you go. Also love those continued Instructor/teacher relationships. How cool is it to see your student have such respect and do what you taught!
When I was at Chevy, I never got used to the factory because I started off with a Verus thanks to you @ScannerDanner
Hey Dan, your M4 scope multimeter on your verus pro is removable and can be connected with the supplied USB cable for test drives. One lead, works great.
excellent video SD and Tommy thanks
Short to ground is 0 ohms, open wiring or resistor 120 ohms. Tip if you want to see communication you can open the door to get a bus message. Just some input love the video!
good tip on the door
Alex Brophy Simple is always easiest and often best...thanks
It's not a VAG com its VAJ com😀
In my days as an electronics engineer, we'd call something negatively affecting a multi-point differential signaling network as "shitting on the bus".
Nice try, more chumps to add to your botnet.
Paul. The two resistors stop signal REFLECTIONS at each end of the CAN. Just like in your house. When you have cable outlets in various rooms, those wall plug cable connectors should be terminated with twist on caps that have resistance. Usually 50 ohms Z - or 75 or 92 ohms of Z. Stops signal reflections the same way - "absorbs" that energy travelling down the coax (at 65% the speed of light :) so it isn't reflected back to your TV.
Love it guys. I'm an ex tech and its nice to see you guys sharing this stuff.
the gateway is usually used to communicate to diagnostic tool one side and to the other ECUs on the other side using two different communication networks. there is no physical link between the two networks
my guess is they put a gateway to conform the european standards to work in usa
I was working with mazdas. It was same. Very difficult to get info on some stuff!
I work at a BMW dealer and we have a lot of classes learning about bus networks and such. I think that this Volkswagen might operate their bus networks in a similar way.
when you were using the breakout box to measure both signal and resistance I think that you were just measuring on the bus lines for the gateway. like on Bmws we have a gateway module. and it has a diagnostic can line just on its own two wires that only feed to the obd connector. so in that measurement you were only looking at that diagnostic can line and not the can network as a whole.
the gateway module in our cars is Just a translator. we have a few different bus networks. (PT can, K can, most bus, PT can 2 just as examples) and each of these bus networks operate at a different data transfer rate. some are as fast as 10mb/s and some as slow as 100kb/s. But every one of these bus networks connect to the gateway and the gateway is a translator. So let's say the ecu is on pt can, and is sending data at 100kb/s and it wants to send a message to the abs module on the k can bus which is sending data at 10mb/s they aren't considered to be talking the same language. the message that the ecu wants to send must first go through the gateway module to be "translated" into the language that the abs is speaking.
we also use different terminating resistors in our flex day bus. it uses 90 ohm resistors. and instead of having 2 in the whole bus. Each module has its own terminating resistor.
but I feel his pain on the no info thing. on our k can network we aren't provided info on the location of the terminating resistors or their resistance values.
fun fact though. we use fiber obtic cables for the data bus on our entertainment modules like amplifiers and radios. they are very easy to diag no communications though. the bus layout is in series. so you just add in a fiber optic loop at the module that you think is causing the no com to see if everthing else after it begins to communicate again.
we have also started using Ethernet as a way of communication and for being able to program multiple modules at once.
That's right . I'm actually working on a BMW with a K-CAN problem keeping the car from going to sleep. A module is messing up the CAN Low signal. I just need to find which. Thanks for sharing.
Thanks so much for the info!
junk cars
360 Good info in just one message, in stad of one hour + of video time. :)
Thank's !
Does NASA know about this technology? They might want to overcomplicate their rockets to achieve the same thing they did decades ago in the name of efficiency........now I'm just being cynical eh?.....all of this just to drive down the road........
Awesome vid as usual Paul. I hate not having a definitive reference data base(picture.# value.) on what is a good/bad BCM to be 100% sure if the component needs changing.
Am new to using a scope and have been watching your chance and others to educate myself on my new equipment and while watching this video i was wondering if the godaig brake out box kit that i have helped you out testing the tcm off the car as you can connect ecu's and modules directly to your computer have yiu come across or used one off these yet
Difference on the voltage at datalink connector is, the scantool is using higher voltage on signal then the data bus module in the car.
Higher voltage at the scantool is used for the wake up the data bus module on some cars.
Higher voltage is the scantool talking to car and the lower voltage is the car talking to scantool.
Nice video. I think that just with unplugged TCM with attached scope leads on can-bus communcation give all the answer that TCM is no good. My only question is, is there a resistance measure on TCM modul can-bus terminal for verifying that the TCM is no good? ( I do not like to much resistance check)
great video guys 👍
Terminator resistors are used to prevent echoes or reflections in the signal being transmitted due to some of the energy not being absorbed. A refection of the signal would cause noise or a dirty signal. They are placed at the farthest ends of the bus or network.
As much as people hate working on Euro trash,it's a smart design if you think about it. Otherwise one module can pull the whole network down and you would get stuck somewhere in the middle of the road. Motoyam82 has a video on a Nissan where the ABS module is causing the car not to start.
Great video Paul! I can't wait for part 2! I'm subscribed to both channels and Tom is great! 👍
Nick Nicu can you put the link of te video you mention please?
Got to give my boy Ivan some love for sure. I need to watch it myself so I can learn something.
Ivan even used the AES tool to check for shorts to ground! That versatility is why I was looking forward to watching you use it in this video. Thanks!
Keith from Staten island had a Chevy van the other day with no com, unplugged airbag module and everything worked.
Actually it was a Mitsubishi! In any case the wiring diagrams were easier to follow than anything for Euro. Even the terminating resistors were shown in the OEM diagram :)
You should try a bidirectional test with the tcm unplugged with a trigger on the diag socket traces. maybe they will be an exact match as the gateway should send the command you are sending to the ecm?
another great vid mr danner, i think on this car with the gateway, the resistance check at the break out box doesn't tell us much, as you said on other cars without the gateway it woulld be a valid test.
Could the difference in the resistance values at pin 6 and 14 been due to added resistance in the Circuit going through the breakout box and length of wires?
Revisiting this 6 years later would you have approached this differently? I’ve been starting with description of operation for communication. Lots of good info such as terminating resistor locations. Then to the schematic to see lay out and test points. Did this vehicle have resistors in gateway from the DLC? I know that’s now a common thing. Was that where you were getting 60ohms? Or was it in fact tied into the CAN bus from the DLC? And if so why the difference in wave forms from DLC compared to back probing modules?
you guys are great
Hi there guys. I know this is an old video so you may not see this and it may have already been mentioned but the reason you were getting different readings with the scope and multimeter when testing at the DLC and the TCM is because they are two different networks. There are multiple networks that are separate from each other hence the difference in readings. I hope this helps and apologies if it has been brought to light previously. Love the content guys, I’ve followed you both for years. Much love from a trainee VW Diag technician from the UK ❤
For sure! We've learned a lot since this time. In particular when the DLC is wired to a gateway only. Thanks!
@@ScannerDanner No, thank you. You have no idea how much I have learned from you over the years. I’ve been watching your content for the best part of 7 years. 👍🏻
@@jackstevens9907 thanks so much! That's awesome
Thanks , for video
I love datalink and emissions troubleshootingn
dude you should work on toyotas and nissans it will be so helpful for us here , i am from COSTA RICA we dont get many american cars here do to fuel ecomony , your videos are excelent you are a very good teacher . compare to all other videos ive watch, you are the best. only thing is here in COSTA RICA we learn and go by ear lol since we dont have the tech equipment you have snap on... here super expensive we dont get pay much here like for example if i was to replace a cluth on a toyota 4x4 ill only make like 150 dollars labor compare to USA, MAKES A BIG DIFFERENCE , so we go as we can , learn and trouble shoot and handle it as we can with no sophisticated tools lol okay i just wanted to say thumbs up keep the good work
Another Tico here. You are correct. I'm one of the few who own an American car and I have to work with what we have. Problem here is,, modern cars with intricate systems and no equipment to diagnose and repair. I haven't seen one Snap on scan tool or smoke machine in any shop around here.
Pura Vida!!
TRUE . THAT PURA VIDA PEACE.OUT
The breakout boxes are bad ass I use mine a lot when I have network issues helps me find problems quickly on the network. You could of always cut the Tcm out of the network and checked it's output seperately
What I believe those resistors are doing is stopping communication from going back to the other module as an echo if that's easy enough to understand the way I explained I don't know how else to explain it
Exactly, termination resistance (always at the physical endpoints) stop reflections from the high speed digital transitions from degrading the signal quality. The sad thing about this case study is that the TCM could probably be repaired by replacing one integrated circuit inside it. It might even be something as simple as a capacitor, resistor, etc (passive parts) on the board. Somebody will replace a $1 worth of parts and sell it as a refurb. Whatever happened to kill it is probably killing them on a daily basis.
Cool video.
does the gateway have diodes inside preventing messages to be sent toward the data connector?
Nice video
Top Video fantastic team work, as teacher is very rewording to see are students doing well thank you for you commitment keep up the good work
yes it is! Thank you
Thanks guys
you were looking at the dlc. nodes reporting to the gateway will show. breaks in recognized communication of known protocol shouldn't show at dlc. that's why you get a no comm when pulling codes. Right?
The K and L lines are used for scan tool communication. K -line from module to scan tool and L-line from scan tool to module. Also, the gateway is used as an intermediate between the different can speeds: High speed and low speed.
You can still measure the resistance of the network at the DLC with the gateway in between because from the DLC to the gateway is considered as the CAN C diagnostic. At least, that's what I understand. Also, the CAN Transceiver in each module, is responsible for the voltage difference.( 2.5 to 3.5 and 2.5 to 1.5).
Great info! I have since learned all this but really appreciate the comment.
Thank you for the info, I have two 2000 Jetta's and one is a manual and the other one is an automatic, and I like the automatic a lot better, but the one that had the manual is in way batter shape and I installed the engine with the automatic in to what was the manual, everything works good running, but the transmission now is not shifting, it is just in sec gear, I replaced the wire harness that goings from the auto trans in, but one if the plugins I do not have a place to plug it in to on the grey plugin, is that why the car is not shifting ? you maybe know what I mean or taking about, under the windchill motor on the left side there is that big cover where the wires and plugins go, and the colors are white and brown and orange black blue and the grey, and the grey there is nothing there. any idea if it has to be there? I do not know what that one does, Thank you
The terminating resistors in the network are there to keep information from "echoing" back into the network
I'm a master Volkswagen Tech myself been with Volkswagen 14 years you probably could have used I wire it's a little better and I wish you pulled out the Otis scan tool yes the engineers they don't give out so much information but the next step would contact techline with your diagnosis and they would say put a TCM in it
Need your help
Can you help me
Crank no start 2007 gti dsg PRNDS lights flash on dash
Master tech wow
😂Good for you buddy! Call your tech line and maybe they’ll send someone out to do the diagnosis for you🤦🏼♂️
So was there a gateway module so pin 6 and 14 could not be relyed upon ?
Yeah, we used to bust Tom all the time about using 'your' DVM. He does sound a bit like you in the videos as well. Nice collaboration, but I'm still unclear about the terminating resistors on the CAN and modules. I thought the TCM would have a terminating resistor of it's own. I agree with you guys, it would be nice to have a way to verify that the TCM is defective above and beyond how the CAN lines appear. Thanks guys!
many different configurations as far as the terminating resistors go is what I am learning
With putting resistors in the circuit it provides a feedback into the lines so it's it's designed to stop interference that's why the patterns are mirrored you take mirrored patterns and you connect them via resistor they cancel each other out
high speed data comm faults is one of my favorite things to diagnose and i specialize on gm products. it appears unfortunately Volkswagen does not have main wiring schematic that shows a high speed lan schematic like gm does. basic principle is 120 ohm resistor on one end, usually an engine control module and a terminating resistor built into the body harness or a body control module on the other end housing a second 120 ohm resistor. both working on a no problem car using ohms law is 120 ohm divided by 2 modules = 60 ohm of resistance at the dlc pins 6 and 14 with all modules asleep. add usually 1.8 ohms of resistance for the 20-30 feet or wiring looping around in series. 61.8 ohms is a very common number i see on a majority of cars. i think 68.8 ohms is way to high even though Volkswagen states 60-72 ohms normal. most common things i see disrupt this data comm network is aftermarket devices usually plugged into the dlc that have to much or too little resistance and send electrical noise into the system. once in a great while i see other oem modules get internally shorted and lower the data comm resistance to lower than 60 ohms and cause intermittent loss of communications and symptoms are noted like no electronic power steering or harsh shifting and gm's stablitrak light. i've seen a 2017 silverado diesel truck with a lift kit have 47 ohms or resistance in the circuit and get's intermittent stabiltrak lights and codes state loss communication with several high speed modules like u0100 as history code. tracked it down to aftermarket speed controller manufactured by hypertech designed to correct the speedometer for the oversized tires. it is tied into the high speed data communication circuit and is causing all this mayhem. i wish i was there to help you diagnose this one. hope you found my insight helpful
VAG wiring diagrams are horrific to interpret!
Thanks for the insight
A different but great way of perfoming a diagnosis Paul - having another tech do the job whilst asking questions to clarify the steps involved. I would like to see more of this approach in the future.
I am wondering if you intend to deliver video tuition on network operation on your premium channel or this a different department of Rosedale Tech
I do plan on doing some network diagnostic training but I need to learn it better first myself. Only by having cars with these types of problems can we refine our knowledge to the point of being able to teach it as your own. Make sense? There are more variables than theory teaches on every subject, that we must see first hand to really grasp. Wait until you see part 2
DiagnoseDan (your dutch counterpart ) had an explanation in his can bus video of the purpose of the resistors
hey scannerdanner I have an question. my question is. I have an 01 Ford experdition 4.6 liter engine. it has a miss in the engine under load. I changed the sparkplugs, test fuel pressure. on fuel test I got 30psi engine off and 40 psi with me power brakeing it and pressing the gas. I feel like an ign coil. but I cant afford to replace them all. but I don't have spec for ohms reading of the coil sec or primary side. but with miss being on sec side should be something dealing with sec side of ign. like spark plug maybe compression or the coil. im I correct. maybe next step is to pull the coil under load why it missing or ohm it out? thanks for help. this is my personal vehicle
i think you'll find the number prefix for ecm central electronics etc will be the binary code for that componant
so, the unplug-it test verified that the CAN wires were good?..(same as say, MAP sensor signal circuit integrity testing?) and since u believed that the other wires(pwr n gnd) were good..the only option was a bad TCM? correct?
The termination resistors are there to absorb the leftover voltage so that it doesn't "echo" back through the wire which has nearly no resistance. Essentially they absorb some of the load to keep the line clean and not staticky. Good question on what generates the voltages, I am not aware of which module does it or if all of them do it.
I have since learned that ALL of them do!! That was one of my main questions early on that no-one could seem to answer. Thank you!
Offboard Diagnostic Infromation System. Very different than VAGCOM. They both have their place but very different. VAGCOM is nice for quick basic settings, code pulling, output tests and non warranty related repairs. ODIS allows for diagnostic "test plans" to walk though difficult trouble shooting, component protection, login access to secure areas of control modules, coding, programing, key adaptation and various other "dealer only" functions. It also records diag logs to submit for warranty to prove failures and countless other functions. It is after all the dealer scan tool and lets you do everything.
very professionel
Once the ECM is communicating with the scan tool , pin 7 LED will begin to flash on the CAN Test Box if not the scan tool is not sending the command to communicate.
From my experience, these communication termination resistors keep signals from trying to go back up the way it came. When working with DMX 512, the standard for communicating with moving lights, you daisy chain all the fixtures together. at the end of the line, since there are no more fixtures to connect, that signal wants to try going back home so to speak. a terminator (which is a connector with a resistor bridging two of the pins) is used on the output f the last fixture to prevent any issues with the signal.
Watching this video. Having a similar issue. Multiple failures around communication. Dealer replaces the gateway issues continue. Guessing bad canbus wiring and need to repin a harness or rewire some section of canbus
The resistors are there to stop voltage spike when data is being transferred
So one question ....well maybe two ...before you plug in the new module ....what killed the old module how are you to confirm that the problem is in the old module and not a problem elsewhere.
u both best
Humble Mechanic VS Positive Lead Diagnostics !!!
I was told the resistors in a can network act as "echo" reducers for a clearer signal. Think sound deadening walls in a music studio. I'm not sure that's the main reason but just what I heard.
I heard that sometimes you can disconnect the battery and reboot the system sometimes
66.8 is considered good, as the resistors have quite a high tolerance so you will never get an exactly 60 Ohms measurement. My VW Golf has three or more CAN networks. I believe the Powertrain one is the one you need and are on.
I agree with you on the VW wiring diagrams, I got an ECU pigtail and the colors and connections are off by a high margin. CAN high is supposed to be pin 79 in the 91-pin connector. CAN Low is supposed to be pin 80 in the 91-pin connector.
The Pigtail has one connection on 79 with a different cable color, and no connection on pin 80. I have the original VW wiring diagrams, just like you guys have.
If the ODB sniffer is the same as the one I have, one switch is for 12 V always on (30) and 12V Ignition (15). I have the Godiag GT 100+.
The K-Line is a one wire network for the different connections in the background going to J533 There is a LIN bus in there too, another one wire network going into J533. There is one for the Radio/Video and such, called MOS I believe. It's a Glasfiber network. On my Golf anyway (2017 Golf Hatchback 1.8L Gasoline powered). The 5V reference circuit is created in the ECU I believe. It has the 5V regulator. But I'm sure you know all that stuff by now.