CAN Bus Wiring and Protocol Explained (Part 2)

"How a communication bus is wired determines how you diagnose it!" In the second part of this three part series, we dive deeper into CAN Bus wiring and how to breakdown networks even further. While still taking a real world approach we will discuss the differences in network topology and the protocols used to speak on them.

#cars #learning #autorepair #diy #fixed

[tonyb]

You Sir are a DAMN GREAT TEACHER !!! As a 30yr USAF Acft Tech, , from 17yrs old, I have trained dozens of newbies from "this is a multi-meter" to fully qualified C-17 Acft Electro-Enviro Techs. I LOVED finding what each person needed as THE way to describe/relate the 'tech info' in a way that was EASILY UNDERSTOOD and REMEMBER-ABLE by them... The C-17 is VERY similar in it's data bus configuration, with physical differences of course. I am now 'learning' automotive for my side gig and you are a GEM! EVERY question or curiosity I had has been EXPERTLY answered by you...JUST as I did for all those people I trained! THANK YOU!

[heny]

I rarely comment, but I'm compelled to tell you how much I have enjoyed every minute of your teaching, it is very well presented, with great explanations and covers the topic thoroughly. Thank you so much, please don't let us wait too long for the next instalment! Keep up the excellent work!

[JesusFernandez-fv]

Hi Ryan, thanks for these three classes. You are an excellent teacher! Even though it has been a year, I decided to comment on this video after watching the last one.

I am an Automotive Engineer and I worked in the design of some of the CAN networks for vehicles.
On minute 23:18 you asked why those sections of the CAN network are different (one spliced with junction connectors/splice packs and the other spliced with ultrasonic welding). This can happen for different reasons. The structure of the harness, available space in the car, the supplier manufacturing process (sometimes different suppliers for different harnesses), etc. But in this case I'd say it is for safety reasons. We have important/priority/safety concern modules connected to that network so we want to preserve the integrity of the signal on those wires. Every time we add and interconnection we loose some of the signal strength (sometimes it not significant) and we also add more points or mechanical failure (swapped pins, water ingression, bad connection, etc.).

Hope this helps everyone to understand better the part of the Architecture and Wiring design.
Last but not least, I hope you get back to doing more videos. As I already wrote, you are an excellent teacher!

[cpcoark]

I said it for part 1 and I'll say it for part 2, Excellent series. I have a EET degree so I understand everything you said. You really tied it into the operations of the car. I am learning a ton from this series.

[keithbrown]

Simply the clearest network training I've seen. Many thanks👍

[angelpaws]

An Auto sparky with 35 years experience and working on can issues daily, this is well worth your time to watch! I'm going to try this method for sure.💯

[jtoddowen]

Part 1 and 2 were both excellent, so thank you. After 35 years in the business, albeit not automotive, I've never heard the term "protocol" used the way you did. CAN was modeled after RS-485, even using the same 120 Ohm characteristic impedance on the differential bus (in most CAN implementations). What you call "protocol", people in my industry call the "physical layer".

We make this distinction because the Open Systems Interconnect (OSI) model differentiates seven distinct layers of a "protocol". Above the physical layer is the "data link layer" where the "hardware" addressing part of the occurs, like a MAC address on Ethernet. This is followed by the "network layer" (like an IP address) and so forth. These can all be considered separate "protocols" or all part of one big "protocol".

Your emphasis on the wiring topology was excellent and a frequently overlooked part of the diagnostic process. When you grew up before CAN existed and still work on pre-CAN equipment, you naturally did / do this, but too many technicians today just want to use a device--so thank you for emphasizing the basics!

[KeepWrenchin]

Definitely the best can bus training video ever. Very complicated subject spelled out in a way that unravels the complexity and uses practicality as the foundation for the explanations leading to simplified understanding and near immediate practical application. Thank you sir!

[spirokattan]

What a great learning series Ryan! Looking forward to the next part! Thank you!

[smiles]

Thanks Ryan! I am learning alot and you are taking alot of the confusion out. I understand that these companies are getting more complicated with their systems for security and such. But paying extra for the info we need is getting old. I believe they are wanting you to go to the dealership for repairs and holding their info for this reason. It will be propieritary info. I believe that the forklift industry does this. The days of fixing your own car are slowly going away. I've racked up quite a bit of money just in subscriptions to get info lol. Lets hope we can stick together and keep that from happening. Thanks again!

[mikechiodetti]

The configuration breakdown helps to understand what your dealing with. I know SMA Eric O had shown how to break down the system to locate the problem including jumping the wires at the module connector for the pass through testing. Your training gives the basics to build on to make it easier to understand.
Before I retired in 2016, I had limited involvement with these systems. Now it seems like that's how these vehicles run, that is, on module communication.
Thank you for this video, looking forward to the next one!

[allinmuza]

Thank you very much for taking your time explaining something difficult for free much love from Zimbabwe

[raphaelndubane]

OHHH RYAN THIS A BEST EXPLAINATION OF MULTIPLEXING I HAVE EVER HAD, YOU HAVE MADE ME ASKED MY SELF SINCE YOU LOOK SO YOUNG, HOW DID YOU GOT THIS VAST AMOUNT OF KNOWLEGDE, HOW MUCH DEDICATION HAVE YOU PUT INTO IT, I REAL WANNA FOLLOW YOUR BRAVO

[andymitchell]

Thank you for this video. I recently had to clone an ecu for my saab and even though it was successful I was still struggling to understand alot of it. This video helped me tremendously and just wanted to say thank you for sharing your knowledge!

[danspears]

Exactly I’ve watched Hundreds of videos and was always lacking what you just shared and didn’t realize it until it becomes time to diagnose network system fault on the vehicle then all of a sudden it wasn’t so clear thanks👍

[arthurfricchione]

Ryan another very well laid out course. Did I grasp it all probably not so I’ll watch it again and grasp some more knowledge. It’s called learning. You have given my self a whole new perspective on. Now it’s up to me to pull up schematics on my own vehicles and try and follow the roadmap you have given us. Thank you for taking the time to put this course together. Artie 👍

[HarpritSingh-bwuo]

Just awesome, eagrly waiting for the next classes, Best communication training with reallife knowledge

[alrifainidal]

Excellent series. I am learning a ton from this series.

[misaelcervantes]

Thanks for your support and help us to be better mechanics

[alexkravchyk]

Awesome lecture. All information presented in brief, practical and concise manner. Can't wait for part three.