Network Communication Testing: K-Line, Serial and CAN Bus
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- เผยแพร่เมื่อ 5 ก.พ. 2025
- This video was created to serve as a primer for network communication / information bus on vehicles. I use a PicoScope 4-Channel oscilloscope, PicoScope OBDII Breakout box and SnapOn Solus Edge to show how different types of vehicle information is transmitted on networks. First, we take a look at K-Line and Serial data on a 2001 Nissan Quest. After that, we move on to a 2014 Chevrolet Silverado 1500 and explore CAN Bus and how that system operates. In both examples, I try to provide a sample waveform and some background on diagnostic testing each.
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Components / Tools In This Video:
OBDII Break Out Box (Cheaper Alternative: amzn.to/32nRbtW )
SnapOn Scan Tool
Blue Point Multimeter
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Great job and helpful video. I’m retired Master Tech and GM Journeyman. This is newer for me and I’m having comm issues on my 2007 Suburban. You know as mechanics we don’t take our vehicles to others. So learning about the pico scope and reading the CAN BUS was very beneficial to me. Thanks
@@anetworkservice thank you for watching! The learning never stops!
Thank you! Trying to teach myself these new network systems. I work on scissor lifts/booms, telehandlers and they are starting to use these type of systems on them 😅 and I like to work on my own car repairs since I have a shop so gotta learn it eventually.
Keep the vids coming, you got a subscriber here!
Thanks for watching!
Nice vocabulary, smooth explanation
Thank you! 😃
Thanks for the GDS2 tip!
Glad that was helpful!
Great video and i liked the way you showed k line and tx,Rx serial data besides canbus
Thank you!
@@AdamsAnalysis man why did you stop posting??
Cool. It is my understanding that the CAN+/- resistance reading is 60ohm when all the modules are asleep. It then goes open loop on the meter when modules wake up and communicate.
Thanks for sharing your knowledge.
My pleasure!
Great video. Very informative. Thank you
Glad it was helpful!
SUBSTANTIAL Adam 's Analysis
Very helpful information video thank you very much take care and have a great day
Adam 's Analysis
From Nick Ayivor from London England UK 🇬🇧
exselecte dianostic master mi respecto para ustes saludes noel matute
Thanks for watching!
The connections were fine for the can bus . What you are seeing in inherent to GM can bus . There was something you had mentioned , and I do not mean ot offend , but it was incorrect. You had said that the modules send out the signal on can bus , but then moved back to a correction inadvertently when mentioning that the can bus is wired in parallel. But back to something more important as a tip you can teach your students , if you are questioning the validity of the signal on your scope channels while scoping can bus , simply revert to using 1 channel lead using pin 14 as your ground for that channel and pin 6 as your positive acquisition. By doing so you will now see what the computer sees. The waveform will look perfect if all is well. Think about why that would be before you teach it to them though 😉. Oh and don't forget that the ohm test will soon be gone from dlc and in some cases already is thanks to gateway modules. Some networks use a terminating resistor in each and every module on the bus like VW as well.
Thanks for the comment and the tips! No offense taken, I’ll give the alternative connection a try. The learning never ends!
Differential voltage instead of available voltage on 6 and 14 using a chassis ground?
Can you make more videos explaining more communication protocols like FlexRay or MOST? I loved this video it's awesome.
Thanks! I'll have to see what vehicles I have available with those protocols.
@@AdamsAnalysis Thank you
NO! this dude should not tackle being a teacher... no more sucky videos... I am putting him on my do-not-waste-time list...
Very good video !
I really enjoyed watching ! 👍
Thank you very much!
hiii..what is the difference between k line and lin bus??? is k line just for diagnostic purpose or does it connect different modules for communication???? plzzz suggest????
Hello sir .
Great video y just saw this and suscribe .
Quick question what’s the pico model pls ?
I need one to start bur don’t know what to get on descent price .
Thank you sir
Do you know if Chrysler LIN can be monitored at the OBD port? I don't see a LIN connection at OBD port pinouts. Perhaps it's translated and put in with the other BUS signals?
I am not familiar with the system. I would have to look at a diagram. As you guessed, it most likely exists behind a gateway module. To gain a waveform you would need to make a connection at the gateway side of the LIN or another connector/module on the network.
@@AdamsAnalysis Thank you for your time. I looked over the OBD port pinout top to bottom front and back for the vehicle (07-11 Chrysler Sebring/Avenger/Caliber) and I don't see anything related to LIN. Just seam's strange to me they would have a network on the vehicle that cant be accessed from the OBD port.
very helpful and very profetional
Glad it was helpful!
Looks like the baud rate wasn't correct for the data. Will look like garbage if you don't have the correct sample rate. Not sure if the obd connector has a clk (clock) line. That's used to provide the correct sample timing for serial communication.
Very Good video...I enjoyed it!
Thanks for watching!
Is the Data Bus Diagnostic Tool will really tell us the main fault of the LAN?
It's a great tool that can help add information during diagnosis. It may not tell you exactly what is wrong, but it is quick to turn on and will provide direction.
Question about a break out box. Do they work on a network with a gateway module? I have watched your videos and it seems to me they can only read between the DTC and the gateway. Does the gateway pass through or does it act as a firewall?
The breakout box will not provide a lot of information when a vehicle utilizes a gateway module. As you said, it will only provide that line between the DLC and gateway. When a gateway is present, you have to find an alternate location to gain access to the network you're needing to assess.
Thank you! With your help, I have learned a lot in the last week about these systems.@@AdamsAnalysis
I use one of these break out boxes , but how ironic is it that pico scope test leads dont fit because the box uses unshielded 4mm banana sockets compared to the shielded 4mm banana plug test leads.
It can certainly be frustrating. The newer standard kits tend to come with some adapters at least.
Pico now has the ability to read
Thank you! I was unaware that Pico had decoding abilities. I'm going to have to try that out.
@@AdamsAnalysis they have a video on it.
@@AdamsAnalysis th-cam.com/video/fwPG0mxqK9M/w-d-xo.html
@@AdamsAnalysis longer more in depth
th-cam.com/video/Bc2R462dlac/w-d-xo.html
Thanks Mike!
TQ , you are so clever .
Hello, thankyou for the upload. In a Porsche car I can see that there are 2 k lines, these k lines are going to many control units. One connects to engine cu, transmission cu & alarm. Other k line goes to AC, parking cu, radio etc . There is also CAN wire that goes to all control unit but it does not go to obd connection.
The 2 k lines goes to pin 3 & 7 of obd plug connection.
What do you think is it ok to assume that k line is being used only for diagnosis process & CAN only for communication?
Yhankyou
Without looking at the specific application, I would agree. In many vehicles, the diagnostic communication is a single route to a gateway module. If you're up against a U code, review the enabling criteria for the code and begin checking the specific network for that fault. In the case of CAN, check the general integrity of the network by first measuring the terminating resistors. If the network is beyond a gateway, be careful about how you enter the circuit for a measurement, such as a backprobe.
Thanks for your video!
What brand is your break out box ?
It is a PicoScope branded breakout box. ( Part number PP619 )
@@AdamsAnalysis Thank you
Can you email me if you have any online courses
elgabi70@yahoo.com
So how i can connect my 2003 nissan xtrail 4x4 diesel 6 speed 85kw
thanks for video
Thank you!
Hi Adam, I have an error link when i try to scan my honda civic ex coupe. I probe it and saw on a straight line 9 volt dc and no waveform when ignition key on. I don't know my car must have a waveform the same or likely as your 2001 Missan Quest. I you address that for me, thanks. I don't have resource to find that information.
You have one of your modules holding the line high interfering with communication. Unplug each module one at a time , start with the easiest to get to first.
Hiii..what is L line??? what is the difference btween L and K lines.. thank you
Thanks 👍
You're welcome! Hope it was helpful!
Hi I need to regen my car it's a subaru forester 2009 diesel. I need to regen my filter however my scan tools won't talk to it via K-Line can I ask what tool other than subaru select monitor 2 will be Abe to do it?
I do not have an easy way to check for sure. I would imagine most Launch/Autel or SnapOn branded tools, with the right Subaru software would be able to complete a service procedure like that. A rep for one of those companies should be able to find out.
Adam Please can u help me
I have a golf car mk3 with k- line protocol
And i need to connect other cluster with gm protocol can i connect the pin from my obd of golf k line to the pin of cluster low speed glman pin to reading the
Rbm and speed and temprture can u help me that could i do
thx
do you have any info you can e mail me on using a BOB in diagnosing/ troubleshooting? i am
new to using a bob and like to get some good info on testing network faults.
Caution: Wait for the bus to go to sleep before attempting to measure the resistance of the terminating resistors!
The sample rate was set too low resulting in “aliasing”of the signal.
Or disconnect the battery
@@jonomotive2000 ...really the only way to do it... there are so many differences in vehicles when it comes to the RAP and so many ways to get tripped performing actions that appear to not interfere but do... this dude is sloppy
@@jonomotive2000
P0
@@stevenstanley2552 what
Hello it is possible to send me to pdf of k line communition,. Tanks
hi, do u need a software to hook up picoscope to loptop?
Yes, there is specific PicoScope software to interact with the PicoScope hardware. It is available for download on their website.
@@AdamsAnalysis thanks a lot for the answer
which software do you use in network testing?
Primarily PicoScope to look for the profile of the waveform. Some OE tools have additional software to help ping modules and check for responses.
If a module is not working, will your BOB tell you which one or will it tell you where any problem is located?? Your dirty signal is from your BOB. I do not believe is the money it costs for one of these tools for as little as it does and the labeled information does not match every vehicle for every protocol, I would build my own without the Christmas lights. The DLC is very accessible to get all this info without the need for a BOB. There is typically an accessible module to get the waveforms and resistance value from also, such as the ABS module. I liked the video overall, thanks.
Thanks for watching! The BOB itself cannot provide much information, such as which module is at fault. It is just providing a point of access electrically to the network. The most powerful reason to use one is to reduce the risks associated with back probing a connector, disconnecting a connector or stabbing a wire to gain a signal. More and more manufactures are telling us not to disconnect connectors due to terminal tension issues.
This is Solus?
Yes, a Snap-On Solus Edge
@@AdamsAnalysis Thanks!
hope i can find my problem, im rebuilding a subaru impreza 2016 with the code u0073
I hate that part of the diagnostics , on which you have to use those high tech , expensive difficult to use tools ; a normal DIY person barely we can use a multimeter .
I wish there would be some tutorials where they would show other simple methods of diagnostics ; to be able to use a desent multimeter to diagnose .
Cayyynnn bus -> CAN Bus