HOW TO DIAGNOSE CAN BUS FAULTS [PicoScope 2204A Low Speed CAN] Mechanic Mindset

CAN Bus Diagnostics training now live for $10! www.mechanicmindset.com/share/65
We look at diagnosing multiple faults on the low speed K CAN network. If you want to know how to diagnose CAN bus faults, I suggest using an oscilloscope, check out this PicoScope automotive training video. In this video we look at how to diagnose CAN Bus faults using the PicoScope 2204A oscilloscope. We also look at CAN bus waveform analysis to help you identify CAN bus problems. It can be complicated this simple CAN Bus Fault Diagnosis video we help you identify the difference between high speed and low speed CAN Bus networks and how to set up the oscilloscope to test CAN Bus. We use the PicoScope 2204a oscilloscope to analyse a CAN Bus signal while different faults are installed.
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Timestamps for How to Diagnose Can Bus Faults
00:00 Intro
00:48 CAN High verses CAN Low
02:50 How to connect the oscilloscope to CAN Bus
04:00 CAN Bus oscilloscope settings
06:00 PicoScope CAN Bus waveform analysis
07:08 CAN high short to ground waveform analysis and fault diagnosis
09:26 CAN Low short to ground waveform analysis and fault diagnosis
10:00 CAN high and low short together waveform analysis and fault diagnosis
10:44 Open circuit CAN Bus waveform analysis and fault diagnosis
12:18 How to diagnose intermittent CAN bus faults with the oscilloscope
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[@taidang7437]

Great video!! Not a mechanic myself, but works with electronic systems on transit busses.

[@MiracleMAX]

Well done Mate. I've just been introduced to your channel and find it very interesting. I'll be able to polish up my Pico Oscilloscope skills even further! 😊 MiracleMAX

[@MechanicMindset]

MiracleMAX Great to hear, thanks! 👍

[@arthurfricchione8119]

Great video thanks for sharing. Stay well and safe Artie 👍

[@MechanicMindset]

Thanks Artie, glad you’re enjoying the channel! Feel free to ask any questions if you have any 👍

[@alitehrani3415]

Great video ,best training like always Thanks a lot

[@MechanicMindset]

Glad you liked it!

[@phillipjlynch9340]

I really enjoy your videos. 👍

[@ilovear15]

With my budget all I can afford is the Pico 2204a and hantek accessories, which I will be buying very soon. Thank you for all your videos.

[@1waukesha]

Thanks for sharing

[@kellyreid8230]

Great share thank you

[@MechanicMindset]

Thanks for watching!

[@wannaPreG]

Great guy, am really learning a lot from your videos. Please do you have video on serial communication network, how to diagnose it with scope and what they look like

[@careyautorepairs]

This lad is so clever when it comes to electrical work I wish I had this knowledge and could keep it all in. Such amazing skill for work and buying cheap cars.

[@MechanicMindset]

Thanks! I am really fortunate to have got a job working in auto technical training for Audi and Jaguar Land Rover; part of the reason I know all this 😁 I’m building a full training site, check it out it’s so affordable and packed with diagnostic gems 👍 You can do it too 💪 www.mechanicmindset.com/courses/mechanic-mindset-membership

[@careyautorepairs]

@@MechanicMindset I’ve just bought it I got the 12 months subscription as it’s cheaper and under £89 so absolutely a bargain brother. Very easy to navigate too. P.S. you just need a add a Facebook group for members now so we can ask questions in both the online privet group on the website we have access to I see you’re active inside, and the Facebook one will be good for faster response from other technicians that can help with questions when you’re away for the day. Thank you Darren your private training is awesome and way better than this KZbin stuff as it’s to the point and very short videos we can understand.

[@Middlemen101]

Thanks for sharing your videos. I learned a lot watching your videos. I guess I have to buy me a Pico scope to learn more.

[@MechanicMindset]

It is a powerful tool. Glad you are enjoying the channel 👍

[@lukecartwright1803]

Great video

[@MechanicMindset]

Cheers Luke! Hope it helps 👍

[@toddcytra]

This was very informative, thank you very much for taking the time to help the rest of us understand these systems better. I have a question... through all your tests your car was quiet until you ran the open circuit test. Then came the (dreaded!) BMW chime, seems that was the condition that made the vehicle unhappy. Was that an 'Electrical System Malfunction' error? That's the error/issue I'm trying to chase down in my X5. I'm able to read the datastream in all my modules, so this one really has me scratching my head.

[@donovanlucibello379]

You, Sir, are putting out premium content! Sub'd

[@MechanicMindset]

Thanks, gad you're enjoying!

[@TheCarManUK]

Amazing stuff.Wish I could do this stuff like you i'd open my own garage.

[@sollykhan2385]

if you believe in yourself enough,and most importantly make the effort,then there's no reason why you cannot 'Succeed' why not take that 1st step,,,and surprise yourself in the process ,,, 🙂👍

[@aymaneng6763]

good job

[@MechanicMindset]

Ayman eng Hope it helps! Thanks

[@stephanevaucelles6378]

thank for video

[@MechanicMindset]

stephane vaucelles Thanks for watching 👍

[@ahmedahmed-dt5ew]

im a new subscriber from Egypt excellent work

[@MechanicMindset]

ahmed ahmed Hello Egypt! Thanks for watching, hope you enjoy the channel 👍

[@ahmedahmed-dt5ew]

kzbin.info/www/bejne/pYXSY42gapygi6c this is scannerdannner looka at minute 24 @@MechanicMindset

[@MechanicMindset]

CAN Bus Diagnostics training now live from $10! www.mechanicmindset.com/diagnostic-coach

[@jasonjerusalem7000]

Thank you very informative New subscriber here from Philippines.

[@MechanicMindset]

You’re welcome! Great to have you on the channel. Are you pro mechanic or enthusiast? 👍

[@jasonjerusalem7000]

@@MechanicMindset yes sir I am a mechanic diesel and hydraulic

[@MechanicMindset]

@@jasonjerusalem7000 Awesome 👍

[@arthurfricchione8119]

It’s nice to see that the Pico 2000 series scopes are quite helpful to troubleshoot with. Might not have all the bells and whistles of the much more expensive Pico scope but it’s just what I need. Thanks buddy 😊

[@MechanicMindset]

Very true! It has its limitations, but for the most part it is a very capable tool!!

[@JWYATT18]

I'm in the market for one ... I think this has sold it for me , just all these bytes and data stuff they talk about on the website in the product list ..

[@salmiabdeljalil5251]

Thanks for this explanation. It's interesting Tell me about Flexray bus how to tested?

[@MechanicMindset]

You can test FlexRay with resistance checks. Oscilloscope test is a bit different. You need the correct type of probes

[@melvinbishops105]

Very nice, Do you have a video explaining on how to trigger the signal ?

[@MechanicMindset]

Hi, triggering to this low speed network isn’t the best as there is no defined high or low point. You can trigger to the last part of the message on High Speed CAN as the signal is higher, I do have a video on this 👍

[@GhostRider-fj2wq]

Great video thanks, What happens if we connect the high can bus wire from one ECU to the low can bus wire and the low can bus wire to the high can bus wire of the other ECU?

[@MechanicMindset]

Hi, I think we will get the same results as shorting the CAN high and low together (if I understood the scenario correctly). Glad you enjoyed the video! 👍

[@alibatebi2161]

amazing video is low speed can are fault tolerance too? what if the module itself shorted(PCM).does it effect the can wave forms. thanks

[@MechanicMindset]

ali batebi Thanks for the feedback! Low speed CAN is very tolerant because the terminating resistors are not between CAN High and CAN Low (like high speed CAN). Low speed CAN is possible to work on single wire mode.

[@cristi9944]

When working on the low speed line then keep the ignition on.

[@djamelabedennacerchiba3233]

Keep up the good work . Thanks indeed I do have simple question Do we see any difference in those waveforms if we unplug the coolant temp sensor for ex ? Is there is any difference. Plug and unplug . As we know It s kind of informatin . It should be sent On those modules ?

[@MechanicMindset]

Thanks! No, we can’t really see the difference. The scan tool is the best tool we have to help with things like this 👍

[@shifty2755]

I've subscribed. I have an Australian ford falcon barra. It's got 2 fault codes referring to the can communication bus network in the ABS unit. Would you have any pointers for me? Great channel.

[@MechanicMindset]

I think if you can apply the points in the previous video, you can confirm if there is a comms issue. ie, if you can read codes in ABS, comms is ok at that time. You’ll need to try and replicate the fault so you can diagnose it. Cheers

[@jamesbarratt593]

I have the Autel Ultra which has a scope in it. I figured from a long time back that I would get the cheap automotive scope you recommended and just did. Now I can use my laptop with the scope. The Ultra scope comes from the unit which plugs in to the obd. means leeds out the car window and across the engine. Not good if someone just opens the door. Also by having two scopes I have more opportunity to do stuff. verify readings for one. Let me ask a question. So I have an Audi A4 at present with the customer complaining of a warning of drivers door fault and parking brake fault at start. Then in live data just to let you know the door registers open and closed as its opened and closed. In a scan of the car using Autel Ultra, Brakes module with u122800 saying implausible driver side door control module. Brakes module with u112200 saying data bus message implausible. Instrument cluster with u105400 saying information electronics 1 control unit no communication. Gateway with u105200 saying generator no communication Drivers door electronics with b1468FO saying return msg drivers door closing condition implausible. Comfort system module with b140B29 saying release button trunk lid range performance. Comfort system module with u112300 saying data bus error value received. Passenger door electronics with b148754 saying motor for window reg no basic setting. Info electronics with b153311 saying GSM antenna 2 short circuit to ground. Info electronics with b156401 saying antenna for telephone bracket electrical error. So basically my question to you is wheres your mechanic mindset at after viewing those codes. Seems like majority are signal and data implausible. Would you even consider replacing the door lock to see what if anything, that does?

[@MechanicMindset]

Sounds like a communication problem, but it could be anything. Even something g as simple as a power or ground issue. I’d take it as it came to me and start conforming what is and isn’t working, go from there. Also get more info from customer

[@jamesbarratt593]

@@MechanicMindset I fixed it.

[@jamesbarratt593]

@@MechanicMindset luckily customer had seen the scan data and got some info in his head so decided to go for a new door lock. Wed seen the door lock operating live data but still. So we changed the door lock and in changing it this is what I believe fixed the comms issue. The door control module strangely has white corrosion over the pins. Above the door rubber the window glass was green with algae. So with just a quarter second spray of wd40 on them and after reconnection of connectors. Erased the codes and with a rescan. ALL THE FAULTS WERE GONE.

[@TTRVision]

this scope has common ground (not floating) on BNC connectors, so when using both channels is enough to connect just one ground lead, right? many thanks

[@MechanicMindset]

Yes it is👍 You might like this video next How NOT To Fry Your Scope! PicoScope 2204A vs Automotive 4425A kzbin.info/www/bejne/noTYdoOsp9qcjZY

[@georgebell3964]

Great video,can’t understand why shorting can bus to ground doesn’t damage the system.🧐

[@ishtimal]

AFAIK, and I'm by no means an electrical engineer so this could be wrong, but the CAN-BUS is a digital system. so it transmits 1's and 0's. Supplying ground to the system would in theory just kinda open the circuit sending a persistent 1 or 0. So the computer would be confused as all hell, but no electrical damage.

[@jamesbarratt593]

Got a Nissan Navarra. Cut out mid driving. Break out board shows almost no can low. Like no can low whilst can hi flashing then after say ten seconds the faintest flash like shooting star. Whats the next thing to do?

[@k8myx]

great video thank i have a engine can bus off coming up on my merc viano under the IC module code 9100 can you advise where to start with this i have just ordered the pico and waiting for delivery any help will be great

[@MechanicMindset]

you can also check out my other video where we look at high speed CAN bus - also the video where i look at CAN bus resistance with a multimeter

[@bbmd2200]

I am hoping one day that you will do a no communication diagnosis on the CAN Network. The reason is that you can have a no communication with only one module. In this case, you won't have to check the network because if you have an open resistor in the pcm for example; you won't have a communication path. My question is what do you think the voltage would look like on the scope if you lost one power feed or ground to a module?

[@MechanicMindset]

Hi, great suggestion. I definitely plan to co er more CAN bus diagnostics. This is a good one. To answer the question, if there was a module power supply problem (no comms), the CAN Bus signal will not be affected. The module simply won’t communicate on the network. Cheers! 👍

[@bbmd2200]

@@MechanicMindset I was expecting to see some distortions in the lines as I saw some in a video Scannerdanner and Tomy Wolf did on a no comm with a tcm. Thank you. I am looking forward to more Can bus diagnostic videos.

[@MechanicMindset]

@@bbmd2200 👍 I’ll have a play next time I’m on CAN bus. I suppose the reason I’ve never checks is that when ever I’ve had a no comm fault, the first thing I check is power supply; if it was a supply problem. I wouldn’t even get the scope out. Interesting to know though!

[@alanw5879]

Is it better to use some type of logic recorder, where you can record for some time to catch the fault of it's something very intermittent?

[@MechanicMindset]

Alan W Hi, there are tools like CANalyzer that can log CAN Bus, however they are generally used by engineers for development and testing, not mechanics. There are features in PicoScope that allow us to monitor longer traces like ‘masks’, ‘alarms’ and even the single trigger could be used to capture intermittent faults. You can use the CAN log function if Pico but it could be a long job trawling through the data to find and issue

[@rexjames0015]

A true Frank Massey diagnostic

[@user-iw4hi1gp1c]

where is the link again for the Pico scope banana cables, please

[@user-jd4kp3lp9r]

Working on 2011 volvo xc60 .having multiple codes for laser communication with driver door.cluster.seat climate control windows.all code store in cem .when I pull fuse for cem codes go away.will not return for few weeks.

[@sammykamau2480]

Ihv Mazda demio 2016 disconnected the speaker wire from the rear side of radio n from there the car didn't start please advise

[@alfonsotobon5013]

Thanks the question is can the scope 2204 decoder de can bus??

[@MechanicMindset]

Yes it can 👍

[@dinuprodan1602]

Hi, I am one of your subscribers, 1 month ago I bought the Picoscope 2205 A. I want just to ask you is Picoscope 2205A better than 2204A?,and what is the difference between those 2?,thanks

[@MechanicMindset]

Hi Dinu! Great to have you on the channel! Yes the 2205a is better; you get a higher sample rate which means you get better definition when zooming in to measurements that were taken over a longer time base (ie 10 seconds)

[@dinuprodan1602]

@@MechanicMindset thanks

[@JH09SUMIT]

Can I get a clean RPM signal from the CAN pins?

[@MechanicMindset]

Not from CAN Bus. You’ll want to connect on the crank signal. You can get RPM data from CAN, but that’s different from the ‘signal’

[@mikeemirian3867]

Sir can the PicoScope 2204A oscilloscope works with automotive software thanks in advance if it does i will order one immediately thanks in advance.

[@MechanicMindset]

Mike Emirian You can get it to work with the automotive software. See this video - kzbin.info/www/bejne/eKeweWCJgdFgY5I But I am using normal Pico 6 software here. It is fine. You will also want to buy the automotive cables too. Thanks for watching!

[@diesalweasel]

Hi yes you can you will need to download automotive 6 from picco website and install it and delete the oem.dll file from it it .may not work on the very first go but second no problem

[@WESK18]

im having kcan faults with my 06 bmw e90, when it goes to sleep i see 11v(is it normal?) on can high or low (green & orange/green) dont remember i will need to check again,

[@MechanicMindset]

Sorry, I'd have to check - that might be normal. If it goes to sleep, that's a good sign

[@ilikefishing7858]

hi mate, a quick question. when i connect a breakout box to my Audi a5 I'm not getting lights on 14 and 6? should they light up? 👍🏼

[@MechanicMindset]

I literally did this the other day on my A4; they don’t. But it is communicating. I checked on a scope. Only when scanning vehicle

[@ilikefishing7858]

@Mechanic Mindset so if I plug in a foxwell and scan it will communicate? also how can I get wiring diagram for abs control module? the brakes won't release 👍🏼

[@ilikefishing7858]

forgot to mention I've been following for a while and because of you I've purchased the hantek 1008c and gt100 and so many leads! 😂👍🏼👌

[@MechanicMindset]

@@ilikefishing7858 It should communicate if all is well. You’ll need a diagram from somewhere. You can check the free Carmin phone app; it might have it

[@gantert12]

Hello is it possible to test with only one channel on the scope

[@MechanicMindset]

Yeah you can do one measurement at a time 👍

[@gantert12]

@@MechanicMindset thank you. I was also curious a what steps you would take to reseal a wire is you had to use a piercing probe. I work on equipment where back probing isn’t always possible

[@triplextriplexxx8225]

this is very complicated to do can you make tutorial for begginer ?

[@MechanicMindset]

triplex triplexxx Sorry for that. Yes for sure, I will be making some videos that cover the basics of CAN bus, then the basics of taking measurements. I appreciate that a lot might have been covered there 🤪.

[@triplextriplexxx8225]

@@MechanicMindset my car gives me k-can line fault on 10 modules but car works and runs fine

[@MechanicMindset]

triplex triplexxx what car is it? As you might see in the video; on this low speed K Can, a fault on one wire will still allow the network to operate (single wire mode). But it also depends on what fault code you’re are getting

[@triplextriplexxx8225]

@@MechanicMindset car is bmw e63 every module gives same error, k-can line fault , only PDC gives diffrent k-can low wire fault

[@MechanicMindset]

triplex triplexxx sounds like a problem with CAN Low (without actually looking). You would need to do the tests I do in this video to confirm the fault. Stay tuned for more basic videos in the future 👍

[@micksautoelectrics8750]

Everytime i use my Pico 2204 I can never get a clear signal like you, Also bought the Hantek leads you suggested and its still rubbish : Never seen a square wave yet :) :)_

[@MechanicMindset]

Can you try another laptop? Also make sure the ground connection is good and start with 20v/20ms/div. Honestly, these scopes are up there when it comes to performance. Not using any USB hubs either? Start with battery voltage for a flat line

[@Greg-lo1tl]

I reckon the low speed can needs no terminating resitors?

[@MechanicMindset]

Correct, this is why it can operate on 1 wire

[@techgeek2994]

where to find diagram to know which wire is can low , can high in body controle module cable plug ? :)

[@MechanicMindset]

TechGeek You can search line for ‘car model’ wiring diagram. There is quite a lot scattered around the internet. Otherwise you will have to pay for a service like Autodata. Also check if the car manufacturer uses generic colours for all the models

[@techgeek2994]

@@MechanicMindset found it in bmw ista d . thanks

[@MechanicMindset]

TechGeek Ah ok, yes. BMW ISTA has all the diagrams. I assumed you had nothing 👍

[@techgeek2994]

@@MechanicMindset in my bmw car i am getting PDC kcan low wire fault can i connect picoscope to pdc module to find fault or how do i do it , like to find exactly which wire is faulty , i have also wire signal tracker to track shorts in wires , can i use that ? :)

[@techgeek2994]

@@MechanicMindset how would you deal with this problem PDC kcan low wire fault :) let me know your opion

[@lloydpalmer5735]

hi darren how are you ..jsut upadting you ive been at this car whole weekend ..so now im getting c 3e9,3fo1,4000,4390,444c.444c,452a from a autel ms8s scanner ..from ISTA scan tool its dde s0129 any help appreciated

[@MechanicMindset]

Hi, what is wrong with the car?

[@lloydpalmer5735]

@@MechanicMindset at present no communication with dde...i replace the blue relay ...no.2 and 4 injector activation code s0129

[@lloydpalmer5735]

2010 tourer 320d msport

[@MechanicMindset]

@@lloydpalmer5735 If all the powers, grounds and CAN are good at the module, check for water in the module. If you are reading codes, the comma must be ok

[@lloydpalmer5735]

@@MechanicMindset all that checked ..but heres the ting i drove the car parked up on my took the motor out to do timing chain over the period of almost a month its sat on my drive cpmpleted the mother and put it back in

[@jcmobilediagnostics8611]

Just for future reference you only need one ground. A shared ground allows for the same electrical potential.

[@MechanicMindset]

JC Mobile Diagnostics Yeah for sure, I just do this out of habit now; we have Pico 4425 at work with the separate grounds and used the native BMW DIS and VAG 5051 scopes for years 😂. Cheers for watching!

[@user-pl5qe1or1u]

why is pico saying 2000 series not for automotive use. They want me to get the 4000 series picoscope.

[@MechanicMindset]

You can’t use it with automotive software. And need to be care as 2000 has 20V maximum input

[@saeedjabbar5171]

Hello . Please I have sorento sx 2019 . And there is a fault in can bus data . When I remove the battery terminal and test from the pin 6 and 14 . Resistance is 85 ohm . I think there a problem in gateway . Almost in terminal resistance . If this test is OK. Please tell me where can I find terminal resistance for this car

[@MechanicMindset]

Sorry not sure, usually in common modules like Engine and ABS, or sometime gateway