Test CAN BUS With a Multimeter | Quick & Easy | CAN Bus Resistance, Voltage & Short to Ground Test

This video shows you how to test the CAN-BUS with a multimeter.
What is covered in this video:
00:42 CAN-BUS Basic
01:16 CAN-BUS total resistance test
03:30 CAN-BUS resistance check when there is open circuit in one resistance
04:17 CAN-BUS Voltage Test
05:30 CAN-BUS Short to ground test
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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]

Please watch the following video for more information about CAN-BUS: CAN-BUS Explained | Everything You Need to Know About CAN-BUS | CAN-Bus Diagnostics & How It Works:kzbin.info/www/bejne/mKfceatjeJeLnNU

[@CanBus-li5ky]

Vey good inf this men spend the time to Teach , He. Is the Best , I am a Tech for Gm , this is the way GM Teach you

[@AutomotiveDiagnosis]

Hi my friend, I really appreciate your nice comment and I'm glad you enjoyed it. there also another video for the CAN-BUS with much more details explained, you may find it by the following link: kzbin.info/www/bejne/mKfceatjeJeLnNU

[@Dean-ob7fg]

Very useful and straight to the point. Thanks

[@AutomotiveDiagnosis]

Thanks mate

[@reynaldoclaveria100]

Thanks a lot sir you enlightened my mind. You solved my problem about can bus.you make me feel better and confident automotive technician.

[@AutomotiveDiagnosis]

Glad to hear this video was helpful and thanks a lot for your nice comment.

[@carsrepaircenter4303]

A perfect tutorials, Keep up the good work.

[@AutomotiveDiagnosis]

Thanks 🙏

[@1960livvy]

Great video - I will use this information to investigate the issues on my Jaguar XK8 or eliminate worries about the CAN BUS system - Many Thanks

[@AutomotiveDiagnosis]

Glad you liked the video

[@dogniunsergedouho5361]

What an amazing video!! Thank you so much

[@AutomotiveDiagnosis]

Glad you liked it!

[@AutomotiveDiagnosis]

Check this video too: Testing CAN-BUS with a Picoscope | Reading the CAN-BUS Waveform | CAN-BUS diagnostics with Picoscope kzbin.info/www/bejne/rqmomWh_e8aHnZI

[@chandrakantindapurkar8738]

Good video to watch again and again Thanks a lot

[@AutomotiveDiagnosis]

Thanks my friend. You may also watch the following video for B-CAN diagnostic: kzbin.info/www/bejne/fXXWeJ2eg6ySr9Usi=vJ-AYV0t1At4rLKJ

[@autokiaa9563]

Very informative 👍👍👍

[@AutomotiveDiagnosis]

Thanks

[@rahulnaadh5663]

Thankyou, informative 😊

[@AutomotiveDiagnosis]

Glad it was helpful!

[@bilndadhar2463]

Great and rich scientific video❤❤❤

[@AutomotiveDiagnosis]

Thanks

[@laxonetrc]

Easy to follow thanks

[@AutomotiveDiagnosis]

🙏🙏🙏

[@kingbojackson8822]

Excellent 👍

[@AutomotiveDiagnosis]

🙏🙏🙏

[@10malabdullah10]

Great video

[@AutomotiveDiagnosis]

Thanks for watching

[@dimitricharaia1507]

Super video !!!

[@AutomotiveDiagnosis]

Glad you liked it

[@AutomotiveDiagnosis]

You can also watch the following video with more details about CAN-BUS: kzbin.info/www/bejne/mKfceatjeJeLnNUsi=2mfJ-_n36OUzouGJ

[@suhailautos010]

Great 👍

[@AutomotiveDiagnosis]

Thank you 👍

[@kasems1536]

Thanks

[@AutomotiveDiagnosis]

Thanks for watching

[@AutomotiveDiagnosis]

🙏🙏🙏

[@weiren5371]

very nice video, easy to understand. These days I have used a multimeter to check the voltage at the "input" of the ECU, the can H is about 2.4V, and the can L is 2.19V. seems the ecu is fucked:(

[@Thomas-fc6gf]

I love can bus

[@AutomotiveDiagnosis]

You may also watch this video for CAN-Bus: kzbin.info/www/bejne/mKfceatjeJeLnNUsi=C9bWnhuVPHTqyDkG

[@dimitricharaia1507]

Good super!!!

[@AutomotiveDiagnosis]

Thank you! Cheers!

[@mohamedkhalkallah9342]

Thank you 🇲🇦🇲🇦🇲🇦

[@AutomotiveDiagnosis]

Thanks 🙏

[@user-tw8td1yl1u]

My man ❤❤

[@AutomotiveDiagnosis]

Thanks my friend. You may also find the following video useful as I have provided more information in this video for CAN-BUS: kzbin.info/www/bejne/mKfceatjeJeLnNU

[@fixitfirst7090]

Good work. Is there same resistance check on the body CAN as well?

[@AutomotiveDiagnosis]

Resistance and voltage are different on Body CAN. There is not any 120 ohm resistor as body electrical options can be different

[@darmaauto5108]

👍👍

[@AutomotiveDiagnosis]

Thanks

[@enghaider8322]

Good

[@AutomotiveDiagnosis]

🙏🙏

[@toddthomas3226]

Good video but loose the music

[@AutomotiveDiagnosis]

Thanks for the comment. I personally rather not to have any music on the videos like most of our other videos.

[@pabsmechanic]

New sub here sir

[@AutomotiveDiagnosis]

Thanks my friend 👍👍🙏🙏

[@moramoy1]

I got voltage readings of 2.9 v for CAN high and 1.9 for CAN low. I am checking a dodge ram 2006. What would you suggest to do next? Thank you.

[@AutomotiveDiagnosis]

Hi there, I would still accept this measurement as a good voltage. As mentioned in the video, CAN-Hi voltage oscillates between 2.5 to 3.5 V (yours is 2.9 V) and CAN-Low oscillates between 2.5 to 1.5 V (yours is 1.9 V). This measurement is just a bit different from what I did in the video, but it is still in the range as based on the activities in CAN-BUS and multimeter accuracy, the voltage value might be a bit different for each measurement, the only things that matters is to get something within the range when you measure with a multimeter.

[@moramoy1]

@@AutomotiveDiagnosis These days I am trying to troubleshoot multiple faults in a single vehicle (Dodge Ram 1500, 2006): (From BCM) - B1648, B1661, U0101, U0100, U0121; (From WCM) - U0141; (From PCM) - U1120, U0141, U1411, U110C, U110E, P0058, P0032. The vehicle starts for about 4 seconds, but then shuts down. Do you have any suggestions on how to narrow the main culprit? Also, when checking for resistances and shorts for the CAN Bus, are ALL of them done with the ignition key in off, correct? Thank you for replying.

[@AA-EFI-AUTOS]

Informotive❤

[@GrasnerThelemac]

Yes

[@aymenmohamed1134]

👍🏻👍🏻👍🏻👍🏻

[@AutomotiveDiagnosis]

🙏

[@HerbMoore3]

Is the Ford J1850 bus on pins 2 & 10 tested and diagnosed identically to CAN bus on pins 6 & 14?

[@AutomotiveDiagnosis]

Must be on 6 and 14.

[@davidyonko1101]

I have a question? can a CAN high/low wire be a regular #12 stranded wire ? That’s is what is used at my work In our pile plugs just a regular #12 stranded wire . Thank you

[@mrchew1982]

Shielded twisted pair is better for this because it won't pick up as much interference... But as long as your traffic volume isn't crazy high due to packet loss or your modules aren't losing communication I wouldn't worry about it too much.

[@guevaradelaserna85]

So is there a cable only for high can bus and another one only for the low?

[@AutomotiveDiagnosis]

Yes, two wires, one for CAN-BUS Hi and the other for CAN-BUS Low which are twisted together.

[@eggyburgers7017]

I have a reading of 0 Ohm on 6 & 14 on my Mondeo mk4. Any ideas what this means? I can’t scan codes so there is a problem.

[@connectwithcar]

❤

[@AutomotiveDiagnosis]

👍👍

[@Mewanrahnam575]

More or CAN bus and LIN bus.

[@AutomotiveDiagnosis]

Sure thing 🙏

[@AutomotiveDiagnosis]

How to diagnose the CAN-BUS using a Picoscope and waveform: kzbin.info/www/bejne/rqmomWh_e8aHnZI

[@paho188_iron_phill4]

hi i have 57ohm resistance is that good or to low? and my canbus voltage is weird -0.13V

[@AutomotiveDiagnosis]

Hi there, 57 is still good.

[@jabbarjabbar1718]

Whate is the different between can b bus and can c bus in usa cars?

[@AutomotiveDiagnosis]

CAN-C is the high speed CAN ( up to 1 Mbps) for Engine, Transmission, ABS, 4WD etc CAN-B is low speed CAN (up to 125 kbps) for body electrical units like BCM, smart key and so on.

[@wannaPreG]

Can you help name the various CAN bus line, I heard you said one is called C CAN, I have this vehicle that says vehicle communication Bus C, so can you break down the various Communication CAN, Let say C Can included ( so so and so module ) B , A, D , E…

[@sandybil]

Hi, I have Volvo semi truck and have code : Mid 130 PSID 232 FMI 9 I checked ohms almost 60-65 Voltage 2.3 -2.5 volts Please what you think

[@AutomotiveDiagnosis]

Your measurement for voltage and resistance is good. You may need to check the CAN-BUS connections on TCM.

[@musamuslu4558]

I tried the short circuit test. An ohmmeter value close to 3 m ohm is displayed between can low-gnd and can high-gnd.

[@AutomotiveDiagnosis]

Hi there, thanks for sharing your experience. This shows that there is no short to ground.

[@CanBus-li5ky]

@@AutomotiveDiagnosis because you spend time to give the ? I will put you page on my face book.

[@AutomotiveDiagnosis]

@@CanBus-li5ky Thanks a lot, I really appreciate it. This following video also provides more details on CAN-BUS: kzbin.info/www/bejne/mKfceatjeJeLnNU

[@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.

[@autowow7128]

If we have continuity between each can with ground that’s mean don’t have short? And how to know have a short with positive?

[@AutomotiveDiagnosis]

Hi there, there shouldn’t be any continuity between each CAN and ground, if there is any it means that CAN is shorted to the ground. To check the short to power there are two ways, first is to turn the ignition off, wait for a minute to make sure CAN is at sleep mode so there won’t be any voltage, then you can measure the voltage between each can and body ( positive on CAN and ground on the body), so if you read any voltage (normally if shorted you will get battery voltage) it means that wire is shorted to positive. The other way is to check the CAN voltage when ignition switch is on, so as you see in the video, normal voltage for CAN high is about 2.6 v and for CAN low about 2.4. So if you get battery voltage instead of normal voltage it means that wire is shorted to battery positive.

[@autowow7128]

@@AutomotiveDiagnosis Thanks alot bro, Yesterday iam checked jeep compass 2017, after checking by scann tool we have many cods about CAN > u0010,u0056, CAN C bus , CAN CH bus and many code lost communication with (ECM/PCM , BCM,ABS, BSM ..) After checking can bus from OBD connector the can voltages don’t problem have CAN H 2.9 - CAN L 1.9 and we don’t have any continuity between CAN and ground. Then check the battery voltage the big battery is🔋 full charge but auxiliary battery 🪫 died. After replacing auxiliary battery all problems and cods are gone. In first we had 18 fault code .

[@AutomotiveDiagnosis]

@@autowow7128 Thanks a lot for sharing your experience. I've also had many different faults on CAN-BUS and every time fir a different reason. But it seems that I'm really enjoying of this difficulty 😅😅.

[@autowow7128]

@@AutomotiveDiagnosis Our jobs full of difficults😅 it's tiring solving problems But in the end it is fun. Hope you succeed.

[@AutomotiveDiagnosis]

Thanks 🙏

[@lifea_stone1674]

C-can과 m-can을 같이 붙여도 되나요?

[@AutomotiveDiagnosis]

Hi there, you mean you want to add CAN bus on your cars that doesn’t have Network right now?

[@lifea_stone1674]

No @AutomotiveDiagnosis. I have m-can and c-can in my car. However, m-can is concluded on Android all-in-one devices, and c-can data is also needed, so I ask if it would be good to attach it to the m-can cable.

[@AA-EFI-AUTOS]

How to check if can bus short to positive?

[@AutomotiveDiagnosis]

You can check the voltage between each pin (6 or 14 on OBD-II connector) and body ground when ignition switch is off. there shouldn't be any voltage. Also you can try it when ignition switch is on, this time CAN-Hi must be around 2.6 V and CAN-Low around 2.4 V, so if you are getting 12 V, it means that circuit is shorted to battery voltage.

[@AA-EFI-AUTOS]

@@AutomotiveDiagnosis thank u for reply💓

[@AutomotiveDiagnosis]

@@AA-EFI-AUTOS 👍👍

[@attaallaabdalla439]

CAN resistance between pin 6 and 14 of OBD connector.

[@AutomotiveDiagnosis]

Yeah. Those numbers also mentioned in the video when you see OBD-II connector. Big numbers are just for the wiring diagram. And on the top left you see OBD-II sign and all numbers in small boxes.

[@alannobakht8503]

Your OBD2 Connector Picture numbering is wrong-- Pin-3 is Pin-6 counting from the left not from the right.

[@AutomotiveDiagnosis]

Yeah, some wiring diagrams give two different numbers on OBD-II connector, one is for the ETM and the very small numbers you may see at the top or below the big numbers. Also at the left of the OBD-II you can see two small arrows to help with this.

[@user-rr5sr9re8h]

god

[@MrBouziani2010]

.

[@mrt-ee1zn]

At obd2 port Can high is pin 6 , and Can low is pin 14, why you misslead people with different numbers in this video ??

[@AutomotiveDiagnosis]

I wish you checked the video more carefully before judging, the diagram is taken from the original wiring diagram so we haven’t changed it at all. Secondly, if you look closer, you still see PIN numbers for 6 and 14 that you are referring to which are just written at the top and bottom of the CAN terminals. So wiring diagram clearly shows that pin 3 and 11 are on the ETM and pin 6 and 14 are for OBD connector (shown by arrows at 02:25).

[@mrt-ee1zn]

@@AutomotiveDiagnosis checked again, sorry but still not see pin 6 + 14 referred as can high and can low, you should edit video, beginners can be missleaded :/

[@ravigarage8745]

@@AutomotiveDiagnosis Hi there, yes, I noticed that in many wiring diagrams as well, that there are two different numbers for OBD-II connector (specially on Korean cars), thanks for clarification, I appreciate your work.

[@AutomotiveDiagnosis]

Check 02:08, at the very left side of the OBD-II connector, you see the arrows for OBD connector pins. When everything is mentioned in the wiring diagram we can’t just change the original diagram in a way we like as it may cause more confusion!!