No-start when hot Case Study: Buick LaCrosse (SI Ep 2.2)

After a transmission replacement, this 2012 Buick LaCrosse is still acting up.
Let's see if we can recreate the fault and dig deep to pinpoint the root cause of all the problems.
This was my first time dealing with this type of issue, so I was also busy listening to professor Keith and taking mental notes :)
After this diagnosis, it really hit home how electrically complicated new vehicles are becoming, and how increasing complexity guarantees that more issues and "glitches" will occur as the vehicle ages.
Enjoy the lesson!

[@rickwest2818]

A new transmission?!! That's an expensive blast of the parts cannon!

[@JD987abc]

I get a freeking headache and my eyes cross watching this and listening to you two. Thank goodness for you and Keith and other experts like you who have the patience and logic to diagnose these car problems and solve them. Without you and professionals like you, the auto junk yards would be over loaded with these computers on wheels. I’m from the days of points, plugs, condensers and rotors. Carburetors and fuel pumps. I currently have a 2017 lacrosse with 40k on it and the remainder of a three year extended warranty. I also have a 1981 fiat spider with 36k original miles that starts and runs every time. Doesn’t burn a drop of oil either. My guess is it will run as long as I need it to.

[@NabilChouchany]

This was amazing! I took an 80 hour course on CAN in germany, and keith added so much to it in just a few words... Thank you Ivan and Keith!!!

[@NewLevelAuto]

Nabil Chouchany thank you for the compliment

[@rickwest2818]

What about CAN takes 80 hrs to explain? Lol

[@RipCityBassWorks]

"I don't have much experience with communication codes" *5 years later* I AM the communication code.

[@tducketts]

Tell Keith thank you for sharing his knowledge. That was a great video!

[@NewLevelAuto]

You're quite welcome sir

[@rhdtv2002]

love the Scotty plug in quote at the end. great video

[@paulberumen9258]

Great video Ivan, I have to watch the video 3 times to put attention to Keith he knows this stuff, keep posting this kind of videos thats really interesting.

[@johnshuttleworth6879]

currently recovering from surgery 2 great diagnostic techs delivering gold

[@PhattyMo]

The two resistors are known as 'terminating' or 'termination' resistors. There's one at each physical end of the bus. Much like old network connections,or SCSI computer stuff used (or most any other high-speed bus). It's used to maintain a fixed network impedance,and prevent ringing,and reflections back down the line. (Imagine a signal going out,hitting the end of the wire,turning around,and heading back to it's original source. Like an electronic echo,to any modules listening.) If you're familiar with CB/HAM radio stuff,it's kinda like the SWR thing,with antennas.

[@xbin87116]

Ah, it's like the caps/terminators on the old bnc networks.

[@Robert-vi6tb]

It woud be cool to see what was overheating inside ECM, sadly many are so secret about ECM,ECU repair. It coud have been a 1$ repair and 200 - 300$ Bill. Hopefully No programing and over the top, the spearpart ECM was there to. Why did it fail if its not common ? US trash maybe ? ;) Most stupid place GM puts ECM, ECU is on the engine.

[@bobsoft]

Probably cracked solder joints because of the use of lead free solder on all electronics nowadays , lead free solder cant flex when the PCB constantly heats/cools.

[@calholli]

Same thing with a resonance loop on a stage microphone and loud speakers.... Also, doesn't that mean that they could have ohm'ed those same two prongs (pin 39 and 40)-- On the PCM itself, to verify if that 120 ohm's resistor is there or not, inside the PCM.

[@eddiemartinez265]

What a great spot for the computer around all the heat water smart crazy one ivan.

[@jeffbecker9809]

Every day I learn something. Your channel is awsome, you are not afraid to dig right in. I have been wrenching for many years myself, but always keep an open mind never know what you might learn.

[@roadkill5333]

Ok, how many times do I need to watch this video, before I start to understand what they were talking about! Cans are what I eat soup out of, and buses are what I ride to downtown, and resistors are the girls I used to date in high school!

[@PineHollowAutoDiagnostics]

LOL

[@Tedybear315]

I won't suggest what a "Capacitor" would be listed as then LOL.....

[@roadkill5333]

Capacitor? $20, same as downtown!! Lol

[@felixcat4346]

Love the comment "they want you to call it LAN."

[@stealthg35infiniti94]

The guy who diagnosed to replace the transmission should be fired! Not even close....

[@chriscorts3337]

Great video. Wish I had a mentor like Keith. You are very fortunate.

[@TheDisgruntledMechanic]

Great vid and diagnostics! learn as much as you can with this CAN stuff Ivan. I will bring my Volt to you when it starts going wonky!

[@stuzman52]

Nice work Ivan and Keith on the can bus...

[@jasongraham882]

Love the videos man I have learned a lot from you, Eric O, and scanner Danner ! Communication troubleshooting is a weakness for many including myself. Thanks for sharing and keep them coming !

[@tmanda323]

Folow DiagnoseDan. He knows a lot about networks in cars...

[@donniejohnson7499]

Great video Ivan. You and your friend are incredible. I'm Disabled after 40 years in the automotive service field.

[@Muelli1000000]

Wow! Amazing video! Thanks for sharing this interesting knowledge. I would like to see more of it!

[@8power0]

Please please please keep up the high tech diagnostic videos . This is what is so interesting about your site . Can communication systems are very interesting this is what keeps all coming back .

[@ahill007ny]

Wow!!!! I'm speechless very nice work Ivan and Keith!

[@NewLevelAuto]

Stanley Hill thanks !

[@xerxes456]

Great video Ivan, nice to work with a pro like Keith. Keep up the good work.

[@PineHollowAutoDiagnostics]

this one would have taken me days of research if someone wasn't generous enough to educate the rookie lol

[@logicinthebox]

a gm that you shoot with the parts cannon!!! thanks Ivan, have a great weekend with the gang!!!

[@autoscanning3565]

Excellent video, I had a similar problem with a Jeep Grand Cherokee and almost the same outcome. Thanks for posting it.

[@sandyande]

brilliant thanks Ivan and Keith

[@NewLevelAuto]

sandy anderson and thanks for your videos also

[@djambrosia]

Great video, enjoyed that. The more I learn the less I want a newer vehicle!

[@PineHollowAutoDiagnostics]

I am 100 % with you on that haha

[@larryhurst8958]

You can tell Keith is all about efficiency, no wasted effort or tests. Most of us would have not fixed this Buick with confidence. He is one smart dude when it comes to Dx. But there are many missing pieces to this Buick and the understanding that goes and comes with the correct path to take and the operation of the system. Probably did not need transmission, bad feeling when you install one and have exactly the same problem. Great video, thanks.

[@robertwhite9898]

This was very educational! I’ve already learned a lot ! 😊

[@DavidS11]

Man, Keith is a beast

[@ericcorse]

That was a good one Ivan.

[@guayaco-dm3vu]

Loved this Ivan..Network issues are a Taboo for most of us.. Thanks to both of you Keith and Ivan for sharing.. Keith makes it look easy to work on cars by the wealth of knowledge.Thanks once again.. Hey Keith Please post some of your videos if you ever get a chance,your wealth of knowledge is mind blowing... Need to pic more brains.Lol.........

[@NewLevelAuto]

guayaco3299 my videos will be out as soon as I hit 2000 subscribers

[@DJ-tn7vj]

Getting a BOB after watching all these Can videos. Thanks guys

[@michaelherbert8213]

Wow, the only thing that I was taught about networks was to just look for a signal. But that was a long time ago lol. I have a breakout box too that makes it much more efficient. I don't come across too many network issues. But it has always been something simple. Great video man.

[@michaelherbert8213]

I need to watch this video again and take notes. Thanks again.

[@PineHollowAutoDiagnostics]

Me too!

[@noelcastle3986]

Great video diagnose Dan has a great can bus explanation video also ..

[@somerandomguy3868]

excellent video guys very informative

[@Tedybear315]

I've had good luck with a company from FL that does rebuilds of auto computers. They rebuild 'em and pre-flash them to the vehicle specs. All they ask for is the VIN, Mileage, and exact ID numbers off the defective computer. The charge is extremely reasonable and carries either a lifetime warranty, or you can cheap out and get a 1 year warranty for less $. Last time I had to use their service the bill came to about $250 including core. Once they got the core back, my account was refunded the core charge and it brought the total bill to $160.00. The local shops wanted over $1500 for the repair. $950 of that was a rebuilt engine computer from the 'stealership. Total bill for the repair including rest of parts and labor came to $240.00 after core refund. Just sayin'...at times you do not need to go "Brand New". Always check options. Sometimes yeah you'll get jacked and have to go "New". I would hope the shop that did all this work cut them some slack, considering the transmission might have been a 'red herring'....

[@PineHollowAutoDiagnostics]

Any make and model? Keep in mind this was a "Euro in disguise"

[@Tedybear315]

The last one I used was a rebuilt for a 2005 Dodge Durango. The 2012 Buick here shows used (with warranty) from about $50.00 + shipping. The rebuilt one for the dodge ran $169 rebuilt. Company is called "All Computer Resources" and they operate an ebay store. I didn't find one for the buick in their 'store'. Most likely due to the very low cost on used computers for that model of car. If you can buy one used for under $50-$75 bucks? Most rebuild companies won't bother to rebuild them as the cost wouldn't make sense. The used ones of course have a full warranty, and if they need to be flash programmed that's usually a basic labor charge- And if the programing fails, it's usually covered under the warranty. I was not expecting to find those computers for that cheap all over eBay. Kinda shocking.

[@mr2law]

Great video! And very knowledgeable that guy Keith !

[@NewLevelAuto]

mr2law thank you

[@jamesg7022]

Great video. Those dlc breakout boxes look pretty useful. saves a lot of fumbling under the dash. unplugging the terminating resistor or module with it inside and testing back to the other resistor is a great tip to verify wiring. Thanks

[@cardoc2477]

awesome Keith, A great information, you make it sound so simple, GM should lesson to you. Thank you.

[@NewLevelAuto]

Automotive Technology thanks very much for the compliment

[@wyattoneable]

As I watch this video I'm only a few miles from where your staying. (ha ha) It was kind of cool to see that act up on camera. His special tool was cool too. Nice work Ivan. See you tomorrow.

[@pedrolriveranegron5178]

Excellent Ivan!!!!!! Very common issue on euro -cars.

[@PineHollowAutoDiagnostics]

you mean when they prematurely break down? yup see it all the time haha

[@pedrolriveranegron5178]

TRUST ME!!----They are a headache / Jaaaaaaa!!! Especially bmw's

[@rwrobs777]

This study was.....HEAVY !!!!

[@79wobbie]

nice job guys I learned something new

[@LFTDoffroad]

Very interesting, thanks for sharing

[@allthegearbutnoideamanwest3174]

I've come across the fault a few times, when a control unit gets hot and losses the canbusnetwork, very common on engine ECU with trucks, if you remove the control unit and place them in a cold place like a freezer for a minute you'll find it will work again but only for a short time.. really good video 👍

[@saxdogg69]

That was fun to watch even though I'm no pro. What I do know is, in MY field, I feel like I have a good grasp on things and am a professional. However, she that one person comes along and humbles the shit out of you every time it s a good reminder to put in my learning pants too. That's someone to start a relationship right there....good work guys.

[@FinalStopMobileAutoTech]

Hey man INTENSE VIDEO!!! Awesome!!!

[@CARRJ142]

Another Great Video.

[@DIYDaveOK]

Old SCSI buses on older PC's had the exact same terminating resistor business - the last device on the bus had to have the terminating resistor enabled or the whole thing would freak out. You usually enabled it with a DIP switch. I also recall some really old/networks that had to have something similar to avoid "standing waves" and power reflections on the network that would just ruin the whole thing. Amazing the auto industry is relearning these lessons that the computing world went through twenty years ago.

[@laohantun7404]

Amazing guys...thanks.

[@esmith836]

very interesting video!

[@gladmarchatlein8164]

Hi Ivan, priceless moments and case study in combination with sir Keith. Perfect diagnostic techniques and procedures... ☆ Like this video like hell Ivan! ☆ Thanks for sharing ! Blessing for you guys, Top Diagnosticians.! Regards. 👍😎

[@PineHollowAutoDiagnostics]

Thank you! Keith is awesome :)

[@gladmarchatlein8164]

@@PineHollowAutoDiagnostics You bet sir! 👍😎

[@leebarnes655]

Hard to NOT learn something with that Keith guy taking part in the conversation. His knowledge of how GM curfluxes their own data schemes is priceless, but it's nice to see he can be flumoxed by a simple color mismatch just like the rest of us. Nice one Ivan, very rare stuff being exposed too, keep it up. And just what I wanted, more Keith. Oh yeah, you are pretty good too, :)

[@NewLevelAuto]

Hahaaa. Thanks !

[@PineHollowAutoDiagnostics]

I was learning just as much as you...tossed in the deep end for sure!

[@wysetech2000]

Keith is one smart individual. Hope you learn all you can from him, Ivan.

[@PineHollowAutoDiagnostics]

Absolutely. Keith is a very patient and generous teacher!

[@NewLevelAuto]

wysetech2000 thank you for the compliment sir

[@wysetech2000]

Hey Keith, the compliment is due and i'm Bill not sir.

[@baxrok2.]

Good god, an automotive savant! Thanks Ivan.

[@101fish9]

So much more. Thank you.

[@ttstang43]

man this may be a older video but very good video, ive been to training classes for can bus networking etc and i guess for me, its all about how its explained and presented... this video really clarified even more for me... although i dont do much of this stuff i want to know because well this video made it look easy lol :)

[@Stoney3K]

Those 120 ohm resistors are ALWAYS on either physical end of the bus, that's why they're called "terminating" resistors. They're used to absorb line reflections in the signal, think of the bus as a pipe and the resistors as being end caps. All of the modules are in between them, it has nothing to do with which modules are master and which ones are slave (because that can change depending on how the modules are communicating).

[@cardude5323]

outstanding. this guy must have a god damn IQ of 220. incredible to Keith work on this.

[@crank3646]

My math is wrong or on pins 12 and 13 are connected 4 parallel resistors 60 Ohms . So the result between the 12 and 13 pins should be ~ 15 Ohms or i'm wrong ?

[@wmichaels362]

Good video! I've found the ECM has connector information on it. X1, X2, X3 & some have connector colors too.

[@Walczyk]

Keith is so amazing

[@figibloom]

Hey nice video of chasing down network faults. Diagnosing can networks I like to use a scope just like you guys did to look at the pattern. Then just like you guys did, shut everything down, and check pins 6 and 14 with an ohm meter. The numbers I was taught in school was 50-70 ohms is good, 120 ohms = open in one of the parallel branches, if you see less than 50 ohms lines are shorted together. Also another good test is to use the ohm meter and check either pin 6 or pin 14 to ground. If you read over 1K ohms circuit is good, if you read less than 100 ohms line is shorted to ground. ( these ohm numbers test to ground also apply to several single line networks as well as some data lines) I liked how he showed to check circuit integrity at the ecm connector. I was watching the video and I was thinking to myself, hey you cant condemn the module yet not without checking circuit integrity, and then he did. That was good, a lot of people would just change the module and not double check that. I find it amazing that this circuit is just a simple parallel circuit. Even though each branch could have several nodes on it, but each branch has 120 ohm terminating resistor. Depending on whats wrong with the network and which module goes bad and takes out the network. It is funny to see somebodies facial expression when you tell them there car wont start because their radio is broken or even better a door module is broken and that is why your car wont start LOL. Here is a good article by dave hobbs I read in motor age magazine about network communication diagnosis. www.motor.com/magazine-summary/communication-is-key-serial-bus-diagnosis/ it is pretty good. Anyway nice video, I gave you a thumbs up. Have a nice day.

[@PineHollowAutoDiagnostics]

Thanks for the thoughtful comment, AJ! How often do you come across CAN issues? I'm sure we'll be seeing more communication diagnostics as vehicle networks become more complex. I know in some high-end vehicles even one headlight assembly can have several "smart" modules...

[@figibloom]

Since I graduated college I have not worked on really any network faults yet, but I did plenty of bugged network related cars in college, and I still have a bunch of awesome notes on troubleshooting different networks. There are to many to keep up with to keep it all in my head. For now I just work on my own vehicles and families and friends vehicles, but I still try to keep up on everything. I enjoy learning about technical things. Yes you are right some vehicles nowadays have a crap load of modules, modules on top of modules, crazy networks, and more complex for sure. Well take it easy and have a good day.

[@chungaleta1234]

Arggghhhh my brain hurts, this was too deep!!!! That dude Keith knows his sh*t..... Very very interesting video and issue. Definitely for pros and not DIYers. Great great case Ivan. And Scotty Kilmer quote was great,

[@kirkabrahamson1148]

Awesome vid. Great to see some canbus diagnostic work

[@mobilemechman]

Pretty cool! I'll have to file this video away for future reference.

[@Travisfromoregon]

Great video Ivan, Class 8 trucks have been using terminating resistors for quite some time. They use them in different ways same idea. In J-1939 they use 2 120 Ohm external resistors at the ends of the main backbone that all the various modules are on abs-ecm-trans. etc... and use a highest priority scheme for who gets to transmit first. These ecm's can use separate dedicated data links (private can) that provides information that only the engine ecm sees. These can also be located inside a component such as in a cummins VGT actuator, and in a Nox sensor and After-treatment system. A individual module on the main backbone usually doesn't effect the entire network if it goes down. But a module that is constantly powering up and down, or constantly transmitting becomes the internet's version of the ping of death. Customers complaints in these conditions usually present themselves as a check engine light that came on then after shutting the truck down the vehicle wouldn't crank. As the engine ecm is looking for a signal (data) for which gear the transmission is in before allowing the engine to start. Easy thing about the truck side of this is you can start pulling the module fuses until the network goes back up.

[@PineHollowAutoDiagnostics]

That's great info Travis, thanks for sharing! Are you a truck electrical diagnostic tech?

[@Travisfromoregon]

Shop supervisor/foreman/manager/technician, For a Truck dealership. Used to work as a honda tech years ago.

[@JLafix]

wow, just when i thought you (ivan) could figure anything out given the time. that dude was unbelievable, he is a walking computer, i wish i had a 1/10 of his knowledge... damn

[@chrisb1975]

We have a 2005 Lacrosse with an intermittent stall. After replacing a bunch of parts that were going bad or about to fail the issue still persists. Finally we have narrowed it down to the PCM in a similar fashion but with more crude tools. It was finally after months catching the network issue that clued me in.

[@alanmaier]

Lessee here.... take 1 over-engineered German car (Opel), add that special GM sauce (electronic failures), slap a Buick badge on it to keep the China market happy and this is what you end up with. No thank you.

[@PineHollowAutoDiagnostics]

You hit the nail on the head there man.

[@Mebob2001]

are you trying to say no other auto makers have electronic parts failure? i can argue that point cause ALL have issues. GM is no worse then the others

[@alanmaier]

All makers have electronic failure issues, but GM has a significantly higher failure rate.

[@tytotheler92]

GM used to have great electronics. Now they're junk.

[@tytotheler92]

The reason why I got rid of my Regal. This is exactly right.

[@abdalgadermohamed5636]

thank you, you are great

[@westtexas501]

awesome video.

[@naushadali95]

amazing video.

[@sonsautomotive]

great video...Keith should get his own youtube channel...

[@NewLevelAuto]

Thanks but no thanks. Just keep watching Ivan and he will soon know most of what I know

[@anthonybeaudry6066]

Hey Keith, thanks for helping us all understand this subject a little more each time you and Ivan do a video. Very much appreciate all your efforts Thanks, Tony

[@NewLevelAuto]

Anthony Beaudry you are very welcome

[@chadgardee1496]

Great video

[@QueenCityHistory]

can't believe 69k miles in 4 years and already a transmission replaced. new cars are electronic overpriced junk

[@edwardjames6070]

buick is one of the best american cars, believe it or not. yeah, 69k is terrible.

[@humidbeing]

This guy knows his stuff! Spouting off network bus termination specs off top of his head!

[@PineHollowAutoDiagnostics]

Dude I know Keith is a phenomenal technician...I am humbled every time I work with him!

[@NewLevelAuto]

Chad Bob thank you for the compliment

[@markferraro5250]

great video ivan and keith thanksagain

[@user-kw5qv6zl5e]

The 60 Ohms is two 120 Ohms in parallel. The equation is just R equivalent = R1 times R2 divided by R1 Plus R2 ie 120 x 120 divided by 120 + 120 = 60. Get you calculator out. So in general each module has 120 Ohms IN it or wired right near it. The PCM has, for that circuit, 120 Ohms in the box. There is a PAIR Of CAN wires (usually twisted together , so thats a giveaway) . A good first test is an Ohmeter in the CANH and CANL across the breakout box Pins 6 and 14. If you see 60 Ohms (or very close) things are ok. If you see 120 Ohms... there's a break in the Communication. The U codes...If you can disconnect Modules in turn and you get 60 Ohms back then you know which module ( or wiring to it ) is the problem. If Probing the wires goes from 120 Ohms to 60 then you know somewhere where the break is.If you go right back to a module...CHECK THE CONNECTOR..OR EVEN BYPASS IT before condemning the Module. Further .. You should be able to see 120 Ohms with the module disconnected and check resistance across the CANH and CANL pins going into the module

[@gmtech2012]

Just a friendly tip for you guys on this one. The connector ID is actually written ON the ECM right on the end of the module and would be located under where the wires leave the connector. It will have "J1" "J2" and "J3" if I'm not mistaken which will be the same thing as X1 X2 and X3.

[@abbeyrham4220]

hey i didn't expect to see rocket science...... Great video. Great confusion

[@cojones8518]

Let's stick an ECM right next to a hot engine block and heater hose lines. Extra points for it being able to rattle around. *Facepalm Anybody else getting annoyed that companies are tying everything up with module serial numbers and dealership only parts/programming?

[@edwardjames6070]

they want to force you to buy a new car. are you thrilled about that idea? not me.

[@rickwest2818]

The modules that have the resistors will be at each end of the bus. This is to prevent signal reflections that can continue well into the next bit time and be misread. Also, the modules may talk on the bus even after the key is off. This is why you're having trouble with the ohm measurement being steady.

[@rexanderson5458]

I'd get a borescope to check for bent valves and holes in pistons. I think you have one. Don't trust codes. Drive the car to clear the engine of unburned fuel. Ignore oxygen sensor codes until you clear other sensor codes. Sometimes one code can push other codes back in the back until you replace parts. With no codes, check non computer systems. Get a fuel injector pulse tester and fuel pressure tester to check clogged injectors. Eric has one. If a battery has been taken out, it can cause no codes but a P1000. Get a noid lite set. You won't use it often but you might later.

[@haywardsautomotive6156]

Nice video Ivan! DLC Breakout Box will pay for itself & Keith is a great person to learn from! Are you going to keep going there?

[@NewLevelAuto]

I'll get him back to the island soon 😉

[@haywardsautomotive6156]

Great...Look fwd to more great diagnostics especially network communications the wave of the future

[@matutenoel4833]

good video amigo exselente video

[@NewLevelAuto]

Funny I've never watched this all the way through. I was terrible lol. Could be so much better . Thank goodness you were there to make it a good video

[@PineHollowAutoDiagnostics]

Haha no way man, you were brilliant! Most people can't keep up with your NYC pace though, so I had to slow it down just a bit. That way I could absorb the information myself as well :)

[@NewLevelAuto]

motoYam82 you did play it at half speed didn't you lol

[@trainer2018]

Ivan that was Awesome Dude! Sucks that the eol resistors are inside the computers. On our buses they are external, one in the front and one in the back of the Engine compartment. Keith is a sharp guy, I think your going to learn a lot from him. I was hoping you were going to break out the Pico for this. Pico is awesome for looking at Can Bus, make sure you try it out next chance you get.

[@NewLevelAuto]

busjockey1 aww heck didn't see this , thanks for the compliment

[@sharedknowledge6640]

A few points of correction for future reference. Adding a 120 ohm resistor at the computer would have worked if the problem wasn't intermittent. But, when cold, the internal resistor would have made it 60 ohms and likely created problems. Also, an ohm meter is not 10 meg ohms like a digital volt meter. A DVM set to measure ohms actually provides power (usually just a few volts or less open circuit) to the circuit or device being tested. It's actually behaving as a constant current source. That's how it determines the resistance. And if the circuit being tested is powered by anything else, including another DVM set to ohms, resistance measurements are meaningless. As someone else mentioned, the 120 ohm resistors are termination resistors. They are generally always at the physical ends of the bus they can't be in the middle somewhere. So even if the wiring diagram doesn't call them out, generally one will be in the source (the PCM/ECM in this case) and the other will be at the far end of the harness (the parking brake module in this case). Finallly, the Verus is an amazing device, all things considered, but it's a rather slow scope for dealing with fast data buses. When Keith mentioned aliasing that's what he's talking about. The sampling rate on the Verus isn't high enough to accurately represent really high speed data signals. So beware what might look like a waveform problem might really be the scope struggling near its limits. It's like when a wheel or airplane propeller appears to spin backwards in a video. The shutter speed and frame rate of the camera are "sampling" a fast moving object in a way that creates false artifacts. A scope does the same thing when the signals measured start approaching the max sampling frequency of the scope. In this case the waveform was plainly messed up badly enough it was obvious something was wrong.

[@PineHollowAutoDiagnostics]

Great points, especially with the DVOM producing its own "test voltage" when measuring Ohms (usually around 0.3V). Thanks for sharing the knowledge ;)

[@mikeakridge6555]

An under hood computer's external heat sink should never be significantly hotter than other nearby metal plates and brackets. Computers do not make much heat. This was an early tip-off for me (and I think for you guys as well) that the computer was bad. Your videos are good. I'd like to see one that shows, dollar for dollar, which scan tool/ scope is best. Mike.

[@superlatew2979]

Could also been a bad connection on one of the pins in connector going into ecm. Pin integrity in connector should have been verified. Plugging and unplugging connector may have brought the network back online, might not need ecm replacement.

[@westtexas501]

hey Ivan was wonder if I can get your input on my video keep getting a p0101 on first acceleration new MAF fro. nissan . according to all data at idle voltage signal fro. MAF should be .9 to 1.2 I'm getting 1.39v at idle. idk what's going on I tried to show live readings of MAF at idle I have B+ MAF signal and MAF ground back probed. let me know what you think plz. THanks

[@ronslaughterandalice1018]

Just wondering , if the ECM has a bad resister and you put another ECM in the car does the VIN# have to be encoded into the new one.

[@davidhollfelder9940]

2 bus terminating resistors .. one on each End of the bus.

[@DarrelllCampbelll]

I have a similar issue on my 2011 lacrosse. This issue is my EBCM. I replaced it with a used one from ebay. The used one still has the other cars vin. Can I have it reprogrammed with my vin with tech2 ? Or are those modules vin locked? Please let me know.

[@fieldsofomagh]

Need to see a video explaining what went on in this video. Maybe a bit of info on the can bus and it's operation as well.

[@PineHollowAutoDiagnostics]

That would be Premium Channel material lol :)

[@Gagik5779]

MOSI MISO

[@JOHNPHUFNAGEL]

That was a very interesting video! I have learned a lot but there is a lot more to learn. Can you ask keith where to learn about can bus systems?

[@PineHollowAutoDiagnostics]

Maybe CAN conference in Chicago this September?

[@jamesrossmotors]

What an awesome video on can. Where i was a bit confused was that since the resistors are in series why was the 120k reading still there when the connector was unplugged. I would have thought it would have gone open circuit. Obviously I am missing something. Also the faulty module was found by checking the resistance. If a module that did not have a resistor was the fault would you have found it by un plugging the module and checking the waveform. Can is new to me and I think I am going to enjoy learning it. Thanks Ivan and Keith for a great video.

[@PineHollowAutoDiagnostics]

Take another look at the diagram. The resistors are actually in parallel! If another "non-resistor" module goes bad, then the approach is a bit different and takes longer. You have to know the network topology to be accurate with the "unplug-it" test. Cool stuff :)

[@jamesrossmotors]

motoYam82 Yeah I got it. I was looking at it as a loop rather than branches of the data line if that makes sense. I watch the vids on my phone so the wiring diagrams are a bit hard to see. Thanks for your reply

[@kurtkennedy5370]

I thought I was pretty well educated in Communication systems....Its nice to see others who are educated and know whats going on as well. communication systems seem to scare A LOT of techs. Was this guys a dealership tech or indy shop?

[@anissangf]

I'm currently dealing with this on my 2012 Buick Lacrosse Touring and it is horrendous. 😢 I've been looking for and dealing w| this for four summers now trying to find a solution. I've already replaced the ECM, ABS, BCM and put a new alternator in last week, nothing has worked, no one can figure it out where I am. I'd really like keep what I've worked so hard for but can't keep doing this. **Did this actually work? ** And for how long?? **Is the PCM not the same as the ECM?? Any help would be greatly appreciated.

[@The1979B]

i know its a 3 year video but still have a question, so what would of happen, if when you guys disconnected the ecm plug, the resistance would of been 60ohm, would you have a bad parking brake module?