CAN-BUS Explained | Everything You Need to Know About CAN-BUS | CAN-Bus Diagnostics & How It Works

In this video I explain what is the CAN-BUS, I explain different types of CAN bus including C-CAN (Powertrain CAN), M-CAN (Multimedia CAN) and B-CAN (Body CAN), I explain where you can find the CAN-BUS on the car, how control units are connected to CAN-BUS, I explain what the Gateway is, I also show you on the car how to check the CAN-BUS resistance, how to check the CAN-BUS voltage (with a multimeter), how to check the CAN-BUS for short to ground. I also show you how to read the CAN-BUS waveform using a picoscope.
Please also watch the following video about other networks on cars too:
CAN-BUS Explained (Part 2) | B-CAN Diagnosis | Test B-CAN with Multimeter & Oscilloscope:
• CAN-BUS Explained | B-...
LIN Bus Explained | Everything You Need to Know about LIN BUS | Local Interconnect Network
• LIN Bus Explained | Ev...
K-Line vs LIN-Bus | K-Line Explained:
• K-Line vs LIN-Bus | K-...
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Disclaimer:
Any information contained in this video is just the understanding of “Automotive Diagnosis: Cars Repair & Training Guides” and it is not an official guide or reference, so everything provided in this video is just a share of our experience and understanding and they are provided as a courtesy for your reference only. So, if you are using any part of this video, use the information at your own risk. We highly advise you to check the manufacturer owner’s manual before performing any act of removal, diagnosis, inspection, or repair on your car to know about what you are authorized to do on your car, what the correct and legal procedure is and what risks might be involved, also viewers are strongly advised to consult a licensed person before any sort of inspection or repair. Due to the factors beyond the control of “Automotive Diagnosis: Cars Repair & Training Guides”, we cannot guarantee against improper use of information or tools or systems, or the procedure provided. “Automotive Diagnosis: Cars Repair & Training Guides” disclaims any damage, injury or loss caused by your decision to follow the steps provided in this video.

[@AutomotiveDiagnosis]

You can also watch the following video for LIN BUS: LIN Bus Explained | Everything You Need to Know about LIN BUS | Local Interconnect Network kzbin.info/www/bejne/rJK3oWafo7mAmrc

[@user-rc8qp5xs9o]

thank you so much for teaching .... I have a question.....how many volts must I get on these CAN WIRES on truck 24 Vts vehicle

[@AutomotiveDiagnosis]

@@user-rc8qp5xs9o Hi there, CAN bus is a universal protocol with same specifications. The only thing is you must know what type of network is used on that specific car, so you will know the diagnostic procedure.

[@onesaja10]

I hate wiring with Canbus,ITS not flexible for modify any electrical ITS not allow with Canbus,i like tradisional wiring ITS more simple to understand and flexible and compatible for other electric system' and easy to understand

[@mxmln8699]

I don’t really work with cars, but I’m an IT trainee. Watching this video was really informative, interesting and you explained everything very well. Thank you so much, I have always wondered how the can bus works exactly. Keep up the good work! And also now I understand why the ford focus of my sister in law was acting up with weird and seemingly unrelated error codes when the solder joints of her cluster broke.

[@AutomotiveDiagnosis]

Thanks for watching the video and sharing your experience. I’m glad you enjoyed it.

[@williamcasey6715]

I have never seen a better explanation of the CAN-BUS, I am extremely grateful...!!!

[@AutomotiveDiagnosis]

Thanks my friend. I’m glad you liked it.

[@mzee5533]

This video has explained in details about the can-bus. Hope you keep on getting this type of important info from you guys.

[@AutomotiveDiagnosis]

Thanks. I'm glad you liked it.

[@cennsa140driver]

Thanks, I started working on cars setting point gaps and using a timing light. Now I work on adaping modern engines into older vehicles. The overview was helpful.

[@AutomotiveDiagnosis]

I’m glad you liked it 👍👍

[@jeffhong2135]

Very informative and helpful with clear explanations about Can Bus

[@AutomotiveDiagnosis]

Glad you think so!

[@bandzar80]

Grate material. Don't stop doing this. Thank you👊

[@AutomotiveDiagnosis]

Thanks my friend, more videos to come.

[@halimabdul630]

Your explanation about can bus is awesome... ❤️❤️❤️ I got some new points from your this video. thank you...

[@AutomotiveDiagnosis]

Hi my friend, I’m glad you enjoyed it

[@foxythedirtydog4494]

Great info especially about the termination resistors.

[@AutomotiveDiagnosis]

Glad it was helpful

[@rodp5919]

Thank you very much for the very informative video!! I learned a lot from you!! Keep up your good work!!

[@AutomotiveDiagnosis]

Thanks for watching the video and supporting the channel

[@stephensullivan9829]

I liked your video it has a good explanation for how the basics of this can bus system works. I was hoping that you might have an example of a failure or what really happens when one of these modules is bringing down the can and how you find out which one that is. I did need this though as i have very limited knowledge on a can bus system and working with electrical problems on a vehicle this could be helpful.

[@AutomotiveDiagnosis]

Hi there, Thanks for your feedback. I actually didn’t want to make this video too long. There are more videos coming soon about CAN-Bus and hopefully what you mentioned will be included.

[@hamidelmziny2981]

thank you so much for information about k line

[@AutomotiveDiagnosis]

Thanks for watching. You can also watch the following video for more information about LIN-Bus: kzbin.info/www/bejne/rJK3oWafo7mAmrc

[@paulitopa3375]

Thank you for this insight, looking forward to learning more

[@AutomotiveDiagnosis]

Glad it was helpful!

[@mjb1552]

Im an EC engineer.I found your video information very useful as I have a 18 Accent, installed with a TS7 android player. I was looking for CAN bus to chose while configuring the Android system.I was not sure.

[@AutomotiveDiagnosis]

Hi my friend. I’m glad it was helpful.

[@MiniBrothas]

Thanks for all this information! Really well done!

[@AutomotiveDiagnosis]

Many thanks for watching

[@mohsenmohsen8514]

This video was exactly what I needed to understand the CAN network. Are you going to make any video about other types of CAN too?

[@AutomotiveDiagnosis]

I’m glad you liked it. Yes, many more videos are coming about CAN-BUS.

[@arttellama2408]

What I know is CAN bus is generic called CAN open. I worked in heavy equipment using CAN bus and same as what is applied to small car.

[@AutomotiveDiagnosis]

@@arttellama2408 thanks for sharing your experience

[@bigstuff52]

Thank you for uploading..Very understandable video...

[@AutomotiveDiagnosis]

Thanks for watching

[@isaacdarkey871]

You've really educated me on CAN BUS,thanks so much.

[@AutomotiveDiagnosis]

I’m glad you enjoyed the video, more videos on CAN-BUS are coming soon.

[@rebwarauto-technician2728]

well done, very helpful thanks for share it

[@AutomotiveDiagnosis]

Glad it was helpful!

[@carlitoescarpe5740]

Thanks for your effort to share you knowledge. I hope you can make a video on intire for ABS module specially in ford models. Thanks.

[@AutomotiveDiagnosis]

Hi my friend. Thanks for watching. We already have two videos for ABS module repair on the channel, you can find them on the links below: kzbin.info/www/bejne/oYaqfWhpoLOLiacsi=VY1ownUePjtqpuOX kzbin.info/www/bejne/eaDTk2SGp7Fpi6ssi=noPzx_WXHuMDbSJH

[@abdoalbasha4368]

High explanations man .. thank you very much

[@AutomotiveDiagnosis]

Thanks my friend, I’m glad you enjoyed it.

[@yuvarajaa5044]

Very nice explanation... thank so much and keep up the good work

[@AutomotiveDiagnosis]

Thanks, I’m glad you liked it

[@sk13m11]

Bro thank you for that. You just simplified something intimidating

[@AutomotiveDiagnosis]

I’m glad it was helpful

[@technocris1]

Thank you very much for initiating on CAN Bus communication !

[@AutomotiveDiagnosis]

So nice of you

[@i.fix_iran6097]

good job man, thank you so much for your comprehensive and functional training. your accent says that you are Iranian, am I right?😁

[@elviscarey5270]

very detail thanks so much for sharing

[@AutomotiveDiagnosis]

Thanks for watching!

[@Steve.191]

Great explanation thank you 👍

[@AutomotiveDiagnosis]

Glad you liked it

[@ravigarage8745]

Perfect and well-presented

[@AutomotiveDiagnosis]

Thanks

[@robertszekely7293]

Super video! Thank you!

[@AutomotiveDiagnosis]

Thank you very much!

[@mohammadal-gebaly3046]

Excellent explanation , thank you very much , watching you from Egypt , it is really fantastic video , waiting for more videos like that, thanks a lot.

[@AutomotiveDiagnosis]

Thanks a lot, I’m glad you enjoyed it.

[@keithramdial512]

Can you show troubleshooting step for a can module ,thanks for all your great work

[@AutomotiveDiagnosis]

Sure thing my friend

[@lucasellyson6872]

Great vid. Question though, in end of video you showed what a short to ground looks like on the pico waveform. But if you created a short to ground why didnt you blow a fuse?

[@AutomotiveDiagnosis]

Hi there, thanks for the comment. There was no fuse issue because battery voltage is not provided directly to the CAN-Bus, so there is no fuse for the network, as voltage is provided through the CAN-Controllers inside the control units. So that short to ground will be detected by the CAN-Controllers and will change the mode to limp-home mode.

[@NoorAhmed-pu4yu]

Thanks sir for nice information about CAN system

[@AutomotiveDiagnosis]

I’m glad you liked it 👍

[@Raam08]

Great video brother ❤

[@AutomotiveDiagnosis]

Thanks for the visit

[@mohammadinamshah8370]

very nice explained sir

[@AutomotiveDiagnosis]

🙏🙏🙏

[@nickschuster7618]

I understand your talking automotive but in semis they use several datalinks and terminating resistors are inside of either a module or a starpoint. Example being on a New Cascadia on the powertrain CAN the terminating resistors are located within the CPC and the ACM. Within the PT CAN the MCM is part of the datalink but does not contain a terminating resistor. This is true for both Detroit and Cummins as far as my experience has shown me.

[@AutomotiveDiagnosis]

Hi there, thanks for sharing your experience. Different companies tend to put the terminating resistors in different locations. Most of the times one of them is inside the ECM, and the other one could be inside any unit on CAN-Bus. For example I’ve seen the second resistor inside the BCM, Instrument cluster, interior fuse box and on some models I’ve seen an external terminating resistor as well.

[@matmechanic5909]

Here is always a fan of your videos, thanks

[@AutomotiveDiagnosis]

I appreciate that!

[@gto3370]

Great video.👏👏👏

[@AutomotiveDiagnosis]

Thanks for the visit. You may also watch the following video for B-CAN diagnostic: kzbin.info/www/bejne/fXXWeJ2eg6ySr9Usi=qtnimuGBioaDO7E3

[@weloveups831]

Good video, thanks!

[@AutomotiveDiagnosis]

Glad you liked it!

[@Singh-pu9wr]

EXCELLENT

[@AutomotiveDiagnosis]

👍👍👍

[@nw8000]

Great video can i ask what you call those probe converts are for the multi meter?

[@AutomotiveDiagnosis]

Thanks for watching the video. They are called back prob pins.

[@TurkVladimir]

Thanks Great Video

[@AutomotiveDiagnosis]

Thanks for watching

[@GuySupa]

very good explanation

[@AutomotiveDiagnosis]

Thanks 🙏

[@G3R1PHONE]

amazing content .

[@AutomotiveDiagnosis]

I'm glad you like it

[@alexmessina3383]

HI there, congratulations this is one of the better CAN bus videos. If I can respectfully suggest something that you could clarify: you explained the gateway module purpose and that terminating resisitors. However, given that both the Nav-AV Modcule and the AC Module (M-Can) are connecteed to C Can, you did not make clear how to determine which module of the two is the Gateway. You simply just stated that it was the AC module. Same for the Smart Key Module and the Instrument Cluster (B-CAN).They are both also both connected to the C-CAN. How do you know that the IC is the Gateway. How do you determine that just be looking at the wiring diagram. Yes I understand you could unplug modules until you see 120ohms on the meter, but that is a very long way around requiring often a lot of work. thanks again.

[@AutomotiveDiagnosis]

Yes, that’s right, it’s really important to know which unit is the CAN-BUS gateway. I simply knew that for this car that I presented because it was mentioned in workshop manual, I’ve seen this reference to the gateway sometimes in wiring diagram and sometimes in workshop manual

[@alexmessina3383]

@@AutomotiveDiagnosis ok often it’s not identified unfortunately

[@ncdave4life]

Unplugging modules until you see 120Ω on the meter would find the module which contains a terminating resistor. But, if I understand correctly, that isn't necessarily the gateway.

[@AutomotiveDiagnosis]

@@ncdave4life Absolutely, terminating resistor is not necessarily installed inside the gateway.

[@romannevazno5147]

Great job. Thanks 👍

[@AutomotiveDiagnosis]

🙏🙏🙏

[@TexasEngineer]

Please elaborate on the voltage on CAN HI and CAN LO. What is your reference? Are you measuring the voltage between the two CAN wires or are you measuring from the CAN wires to frame ground? Also, where does the power originate from to provide the voltage changes? Does each module require a 12 volt line and a ground for power?

[@AutomotiveDiagnosis]

Hi there, voltage comes from each control unit as each unit connected to the CAN-Bus has got a CAN controller inside which regulates the BUS voltage and convert the signals to the CAN message format. For measuring the voltage on CAN-Hi, voltmeter red prob on CAN-Hi wire/pin, and black prob on body ground. Same way for CAN-Low but this time red prob on CAN-Low wire/pin. Ignition switch also must be on.

[@giricyber-ps8420]

Thank you for the nice explanation and practical demonstration.

[@AutomotiveDiagnosis]

Thanks for watching 🙏

[@ThunderbirdRocket]

Super helpful ! Thanks you !!

[@AutomotiveDiagnosis]

Glad it was helpful!

[@HariBuan]

Finally some good videos on youtube, thanks

[@AutomotiveDiagnosis]

Glad you liked it!

[@rashidselemani475]

Thanks you so much Sir for revealing the mystery 😊

[@AutomotiveDiagnosis]

Thanks my friend for watching this video

[@paulgreen2364]

Very helpful, thanks!

[@AutomotiveDiagnosis]

Glad you enjoyed it.

[@amarabdelli487]

Thanks for sharing

[@AutomotiveDiagnosis]

Thanks for watching!

[@sohailahmed3101]

Fantastic sir. very exelent

[@AutomotiveDiagnosis]

Thanks 🙏

[@steveroff1178]

I tested according to what I see in your video but I do not see what happens if there is a short to power. When ohm testing 6 to 14 with the key off I get OL. Voltage on pin 6 is 10v and voltage on pin 14 is 8v. The van will not crank or start. The scantool can only communicate with modules on the low speed bus. It cannot communicate with ecm or tcm which are where the resistors are. I would suspect there is a short to power in one of the modules correct?

[@javidasgharzadeh413]

Great❤❤

[@AutomotiveDiagnosis]

👍👍👍

[@wesleywalsh4025]

I Like this video very much. Thanks for putting it together. 5 *

[@AutomotiveDiagnosis]

Glad you enjoyed it!

[@4m4s0]

Thanks for the information. But there was something I'm still wondering. How did you know that the A/C module was the Gateway? Is there any way to check that? Except for just testing disconnecting each module?

[@AutomotiveDiagnosis]

Hi there, thanks for your comment. Mostly workshop manual or wiring diagram are very helpful for finding this kind of information.

[@hareethasrini41]

Hi,How do you say AC control and Instrumentation control alone is gateway.Can you explain how to intrepret that?

[@AutomotiveDiagnosis]

Hi there. Normally gateway is connected between two different types of network. If you have multiple units connected to two CAN-Bus, that one which must be on the car in any circumstances is the gateway. For example, smart key control module is not a gateway as you may have a car without smart key. But instrument cluster is a must on the car. Also, workshop manual can help for finding the gateways.

[@autolovers3446]

I learned a lot, thanks

[@AutomotiveDiagnosis]

Glad to hear it!

[@Walopa_uie]

hellow sir i really like your video from Philippines,, sir how to know the pin out of any module or to access the module pin out, or a link...thanks your teaching us

[@AutomotiveDiagnosis]

Hi my friend. Thanks for watching the videos. I think the following video will answer your question: kzbin.info/www/bejne/aIaYYqivppeZnrssi=iyunZjJ9TV2ueOjk

[@junaidahmed8694]

great video👍

[@AutomotiveDiagnosis]

Thanks

[@user-be8rh6wk9k]

Very nice video thanks you sir ❤❤❤

[@AutomotiveDiagnosis]

Glad you liked it.

[@charleslyell3748]

Great video, thanks a lot. A question: can two modules communicate at the same time or not? Does one communication block another one until it's done?

[@AutomotiveDiagnosis]

Hi there, thanks for the great question. In each CAN data frame, there are multiple fields, the second one is called “arbitration field” which decides the message priority. So if two control units are sending messages at a very same time, arbitration field decides which one has a higher priority. Therefore, the message with the highest priority will be sent first.

[@charleslyell3748]

@@AutomotiveDiagnosis Thanks again.

[@AutomotiveDiagnosis]

👍👍

[@shayanvasseghi]

داداش دستت درد نکنه ویدئوی خوبی بود😁🙌

[@AutomotiveDiagnosis]

Thanks for watching my friend.

[@linkbits1]

Thank you ….well explained 🎉

[@AutomotiveDiagnosis]

Glad it was helpful!

[@dailytechytchannel7]

Thanks for the video

[@AutomotiveDiagnosis]

🙏🙏

[@dipakmanu1842]

A new member is here, just joined the channel membership ‌‌😊 Thanks

[@AutomotiveDiagnosis]

Welcome 🙏

[@MAZHARKHAN-qy2ho]

Hii. I loved the Class. Pls, can u give us more video on Other CAN and LIN network. Thank u.

[@AutomotiveDiagnosis]

Hi my friend, thanks for your comment. Sure thing, many more video are coming soon

[@alaaalbudeiri1064]

Thank you very much it’s really helpful explain

[@AutomotiveDiagnosis]

Thanks my friend, I’m glad it was helpful 👍🙏

[@RivalRx]

Amazing video, thanks for sharing.

[@AutomotiveDiagnosis]

Thanks for watching!

[@Tony-mg8eb]

Wow, very nice

[@AutomotiveDiagnosis]

Thank you! Cheers!

[@rizzygeorge]

hi...i have some problem with CAN..car.is an Audi a6 c6 year 2010....i have no comunicațional with CAN and generator and batery module .....eror j533....have any idea were to look?thank you🍻

[@AutomotiveDiagnosis]

As far as I remember, J533 is the CAN gateway integrated with instrument cluster. So not a bad idea to check it out.

[@Alfon-hz8nw]

Amazing

[@AutomotiveDiagnosis]

Thank you! Cheers!

[@kicheollee7857]

Great video

[@AutomotiveDiagnosis]

Thanks for the visit

[@renellhenwood3516]

Good stuff. What is FD CAN all about

[@AutomotiveDiagnosis]

CAN FD (flexible data-range) is a new development to increase the bandwidth of the initial CAN-BUS protocol.

[@dhruvsingh2876]

Well..If terminating Resistance is Inside ECU, doesnt it disrupt CAN communication when we remove ECU from the vehicle? But as we can see CAN system still works after Removing ECU?

[@AutomotiveDiagnosis]

Hi my friend. CAN BUS is a multi-master network, so, removing a unit should not disrupt the entire network (although I have seen some cases that it does 😒). Anyway, removing the ECM or even a terminating resistor (in case of having an external resistor) will only make the network more noise sensitive and voltage fluctuation will put the other control units at risk, but network must still work.

[@mauroaparicio1855]

great video

[@AutomotiveDiagnosis]

Thanks for the visit

[@user-ii1un6fq3h]

Just subscribed 👍👍

[@AutomotiveDiagnosis]

Welcome 🙏

[@ilike2seeit]

Awsome!!! Thank you!!

[@AutomotiveDiagnosis]

Thanks my friend, glad you liked it

[@flip0x01]

Network looks like Hyundai. What data does the A/C module need or broadcast?

[@amrelshennawy5792]

Plz where is location of can gateway module in kia cerato 2011 I have U0101 lost com. With TCM c-can u0001 high speed can com. Bus off c-can

[@AutomotiveDiagnosis]

Hi there, gateway is the instrument cluster.

[@user-cz9lg4hq4r]

The best

[@AutomotiveDiagnosis]

Glad you think so

[@jeffmech5948]

Nice

[@AutomotiveDiagnosis]

Thanks

[@AASKAROFFICIAL]

Sir can lowcan high wire me voltage kaha se aata hai

[@AutomotiveDiagnosis]

Hi there, there is a CAN controller inside each control unit which regulates the CAN voltage constantly.

[@AbdulJabbar-hc8dq]

very easy

[@GOMAND-4men]

super film.

[@AutomotiveDiagnosis]

Glad you enjoyed it

[@user-ef3rt1ef7i]

Resistors are to avoid reflects waves

[@AutomotiveDiagnosis]

That’s correct, thanks for pointing that out.

[@pault4513]

My 1997 Dodge Ram uses a can bus for cruise control

[@djrigga]

Can bus works on priority it’s language is binary 0s and 1s and everything in the network speaks to each other weather 1 module wants to listen or not the signal passes down the line to where it’s relevant information is wanted

[@AutomotiveDiagnosis]

Absolutely correct. Thanks for sharing your experience and knowledge .

[@DavidGutierrez-zi4dy]

thanks.

[@AutomotiveDiagnosis]

Thanks for watching

[@mwangigateiyu1570]

Do you have a video about k-line network

[@AutomotiveDiagnosis]

I’m looking forward to an opportunity to make one. Hopefully soon.

[@seanlevoy9446]

Yeah this is great and all, but when you cant start your car because the module for the rear lights is out, IDK. When you need to reprogram a turn signal module and you must go to the dealer.IDK.

[@AutomotiveDiagnosis]

Yes, CAN-BUS is really great but it does have it's limitations and problems too.

[@dailytechytchannel7]

How 1/60 becoms 60 ohms sir ?

[@AutomotiveDiagnosis]

When you calculate the total resistance, as I explained in the video, the result was 1/R(total)=1/60 so as we want to calculate the R total, we change both sides of the formula to bring the R total and 60 to the top, so the result would be R total=60.

[@dailytechytchannel7]

@@AutomotiveDiagnosis thanks sir got it

[@hamzajaddour1797]

1/RT=1/60..….....then RT=60

[@AutomotiveDiagnosis]

@@hamzajaddour1797 That's right.

[@mistalobsta]

Well done champ. Nice flow to explanations. Terrible handwriting though. You must be a doctor in real life.. :) :D :p hahahahaha

[@AutomotiveDiagnosis]

Thanks for your comment, sorry for the handwriting 😅, it’s normally not that bad, but for making this video I used a laptop which was not very easy to write on the screen.

[@IrfanKhan-sp3pl]

Where are you form how to contact piz

[@AutomotiveDiagnosis]

Hi mate, you can contact us using the following email address: [e-mail]

[@francismiranda7812]

How to red xf wireing diram

[@AutomotiveDiagnosis]

You mean Jaguar XF?

[@sisayHabte-fe8jd]

fersete how is chan you

[@onesaja10]

I hate wiring with Canbus,ITS not flexible for modify any electrical ITS not allow with Canbus,i like tradisional wiring ITS more simple to understand and flexible and compatible for other electric system' and easy to understand

[@stephenvelden295]

By God! Those new Camrys are UGLY!