Former telephone splicer here. First, you need to shunt the network at the ebcm back to the bcm. Verify that you have a solid 0 ohms (or close to that; temperature, wire gauge, and length of wire will determine the exact value). My guess is that you won't have 100% continuity. Additionally, I'd disconnect the battery to ensure that you don't have any stray voltage. I believe that you will find a spot where the insulation is nicked across that set of network wires, causing a partial open and short. I used to see this quite often is outside plant cables. You'd have a few wires losing insulation and damp, so the wires would corrode, starting adding resistance in series AND IN parallel. Additionally, sometimes, the circuit would be open from one end and have a high resistance short from the other. You could also get crossed with battery from another circuit (that generally wouldn't happen in a car if you disconnected the battery but..). Good luck, interesting problem to solve. Crawling around a car beats tracking down a problem in an 8 mile telco loop.
@douglasreynolds Just a quick question if I may, what do you mean by shunt the network? Im curios thanks. I have more of a suspicion that the induced voltage will be something feeding back from the screen installed since last repair.
@@garryrussell7618 by shunt, I mean take a jumper and short the network wires going to the BCM together. Then, you can measure the continuity from the BCM connector to see if there is a break in the wire.
Ivan, you should build a detached garage and make it tall enough inside to put a two post lift inside and with plenty of space around for your tools, etc. When I had my new house built I had the garage built with the ceiling at 12 feet high to have room for a lift when I'm ready for it.
You don’t want to use those skeevy crimps under a car. And GM should be spanked for putting an electronic module down there. They are doing this all the time. The Corvette also has a computer way down there. Water always wins.
as soon as I saw those splicing beans, my stomach sank. those are made for security alarm work, not high speed, 5 volt data lines. then I saw the yellow wire nuts !! time to teach Jason how to solder and heat shrink
Get a OE pigtail for that and properly do those splices. The person that did that should not touch a vehicle electronic system ever again. Could of at least used the Solder sleeves. I would be wanting to fix that correctly first then chase the issue if it remains due to knowing its a issue.
@@mastahc411 No what was done on that is just being lazy to take time to do it right and spend a little bit to have it properly done. Fact is there is shops that do this crap and sell it to customers and the customer always loses in the end. And you definitely don't practice on a safety related system like the ABS. Be honest with yourself when doing a repair and if its above your skill level pay to have it done properly by a trusted source whoever that may be. There is one thing in trying to learn and quite another just not wanting to take the time to do it correctly. Someone that was just learning would of used unsealed butt connectors which they would of done a bit of reseach to find and not freaking household wiring nuts. This day and age information on this type of repair is easily found. Nobody is perfect but the ones that are willing to put in the effort are going to seek out the answers on how something should be done and deciding if they are capable or willing to do.
Disconnect the battery. Use only one meter at a time (you are reading the input stage of the other meter). Solder and heatshrink all those wire nut connections so you know they are good (needs to be done anyway). Measure each wire individually: connect one side of the meter to CAN high at the DLC, and the other side to CAN high at the EBCM, etc. Backprobe the BCM so you can also measure there with the BCM plugged in. There seems to be a lot of confusion here about what measurements are covering what, and that is what needs to be cleared up first.
This is literally the stuff of my nightmares--I'm driving my Avalon, then lights I've never even seen before start coming on, it starts falling on its face, making weird noises, etc. I wake up, realize it was a dream, and then remember I have Ivan to help me if that happens in real life 😅
This one has got me intrigued. I have no interest in cars. I found this channel as I was searching for a soldering iron, and now I'm hooked. For me, it's about troubleshooting complex systems. Just watching Ivan, and his refined technique, has made me a much better systems troubleshooter, for both hardware and software!
I've never worked on an auto computer network but as a maintenance engineer (retired) I've troubleshot numerous industrial systems. Ivan has the guts to show you his whole technique on video, including the dead-ends. He's a great example and teacher.
I apologize if this has already been mentioned, but an easy way to validate an ohm reading is to reverse the leads at the meter. If the reading is different, there is a problem.
Hi Ivan, I'm not sure if it's part of the problem or not but you need to fix those splices. There's electrical wire nuts on some of them! Not to mention they're on the underside of the car exposed to all sorts of water and water spray. I would trust those connectors about as far as I could throw that Escalade! I don't know if you can get a new connector or not but at the minimum those splices need to be redone and watertight! I'm also not thrilled with the resistance changing depending on the position of the connector bail. I'd fix that whole connector and splice mess before going any further just to eliminate it as being the issue or contributing to it. Thanks as always for another great video, it's fun to watch your logic. I will say you don't cuss nearly as much as I would!
You should NEVER do ohms measurements on live circuits, even if they are in sleep mode. Even any "yawning" data in the circuit will instantly flip the ohms measurement. You MUST decide your method : a) Have the circuit live and do voltage/data measurements or b) Have the battery disconnected and do continuity / ohms measurements You can NOT do both reliably !
So ironic. I had an Escalade do the exact same thing this week. It ended being the radio. The class 2 serial data message coming from the radio was 0 to 13.5 volts instead of 0 to 7. Fixed that. Then every once in a while you go start driving and the stability light would come on and you lose throttle response for a few seconds. Turned out to be the steering angle sensor. It was jumping around from 0 degrees to 162. And when turning left it jump from -220 to 510. Crazy.
Very interesting. I would only say that I would check the resistance with the BOB unplugged. The BOB can interfere with the CAN network on some vehicles, especially if a Scan tool is connected to it. One way it can do this is that it can act like an antenna hanging off the CAN bus. Some Scan tools connected to a BOB on some cars will not even connect, but will connect fine without the BOB. Depends, of course, on the particular BOB as well. This has nothing to do with the root cause of the problem however, but may have something to do with the resistance jumping all over the place. If not, it seems it would most likely be a poor connection somewhere on the CAN bus. I am trying to go by memory here as I don't have a lot of time to re-watch the video right now, but I think which ever CAN line was connected to channel two (Red), was worse than the other. I may be mistaken here though. Once again, very interesting, and thank you for making these videos. They are appreciated.
Many of those “Tesla style” radios tap into the network, could be a new problem introduced. The wire nuts on the ebcm aren’t too encouraging even if the resistance appeared stable while messing with the connections.
I'd see if that aftermarket Tesla screen/radio is part of the BCM . Since it's aftermarket it might have one of those com boxes to make it work and those always cause problems.
Not everything that CAN be fixed SHOULD be fixed. RUN away from those wire nut and shady connections! I would insists on a new wiring harness or not repair it, or it WILL be back!
I don't know if it will influence something, but the first thing I would do is reattach the connector your way to get rid of that variable. If it quacks like crap, it will behave like crap. Maybe the customer does not want to incur the additional cost of getting the connector reattached correctly. In that case he will have to understand the risk he takes. You question the dealer, that is a very good question. Dealers are usually only interested in shooting their own parts cannon :)
I wonder if that aftermarket Infotainment Center is causing this? That huge screen in the middle that replaced the Radio head unit and the hvac controls.
It makes me wonder why the BCM was replaced before. I wonder if there's a windshield leak, or maybe the rubber gromet near the door hinges- and there's somehow getting water dripping on the BCM, and that's why there's yet another BCM failure (if that's even the problem).
I think you know that you can't put two ohm meters in parallel, but also for consistency of testing, you should use the SAME meter at each test point. Crusty faults are non-linear (IE not a pure resistance) so the testing voltage of the meter will influence the reading. This test voltage can typically vary between 0.5V and 5V on digital meters.
Initially, the resistance reading of the network was about 40 ohms too high, then it continued to climb. I suspect a corroded, high-resistance wire between the VCIM and the EBCM. To confirm, I'd isolate the VCIM and EBCM by unplugging them and use an incandescent test light to load the communication wires between the two modules. In other words, I'd use the test lamp as a continuity tester and use the communication wires as the jumper wire to complete the circuit. The circuit will likely only see 8mA of current during normal use, so I'd want to stress test the wires by ensuring they can carry at least 250mA.
I would bypass the can wires going to the bcm and plug everything back and see what happens to the ohm readings, or check for any "added" power gps or alarms that maybe tied into the Bcm..
There has been times that I contemplated yanking the whole harness in a car, and rewire it with a universal hot rod harness and ditch the computers. But your knocking off the problems on this one a wire at a time. Would be good training for other automotive techs. 👍🏻👍🏻
Creepy déjà vu! Not sure if it's easy, but I would have started in the 120 Ohm resistor to set a baseline, and go back measuring through each module (maybe also reversing the leads to compare - if there's a parasitic voltage, there could be a module leaking irregularly in sleep mode). Very curious of what Part 2 will bring.
You can test to see if a voltage is affecting the DVM reading by switching the DVM leads (polarity). If the reading is different with the leads switched, then a voltage is throwing you off. And for testing purposes, you might need to disconnect the vehicle's battery until you have the resistance measurements sorted out. If the resistances are OK with the battery disconnected, then it looks like a bad module may be the cause - and you're way above my skill level (I use the term "skill" very loosely). I can't wait to see part 2!
Good stuff Ivan.... cut the net in 1/2... 1/2 good 1/2 not .... so cutting the bcm out of the loop and the other 1/2 of net's good? then bcm for sure? .. thanks for sharing your time.
An ohm reading that starts at 0 or very low and then climbs can indicate a capacitor in a circuit. There may be one of the can lines is open at some point... That's from my electronics past...
Need to do wiring repair at the ABS module. Clean, tight connections are a must on low voltage circuits. I think either a bad connection at a module or a possible corroded wire that hasn't broken all the way through yet.
In my opinion, having electronic modules with an exposed main connector underneath the vehicle sold and operated in the rust belt is just crazy. This module should be in the vehicle and not under it. Add to this the connector swap with all the splices, again exposed underneath the vehicle, I feel is not reliable. You would have to somehow seal the module and the harness so they are not exposed to water (or hold water) and salt spray. I would have removed the module and inspected and cleaned the module pins on the bench. For inspection on the bench I use an electronic repair type stereo microscope. If the module pins are heavily oxidized use Deoxit D5 spray to rinse and clean the harness and the module connector. Then apply Deoxit D100 with needle applicator and mate the two. Then disconnect and mate again. If you do several mating cycles (like 4 or 5) the Deoxit D5 + D100 will start to breakdown all of the oxidation and provide a noticeable lubrication, meaning the connection will feel easier to seat. When the pins mate smooth and easy you know they are clean. In my experience, the 4 or 5 connector cycles used in this cleaning process will not effect pin tension. You can try this yourself on the bench if you have some old oxidized machine barrel pins, like Deutsch DTM series pins, and apply Deoxit (use D100 with the needle applicator) and do some mating cycles with a single pin connection and you will notice the pin connection wiping action cleaning and lubricating the connection. The old oxidized pins will be cleaned completely with the repeated mating and mate easier.
If there's anything still live on the CAN and adding voltages outside of the meter you'll get "off" resistances (ie, bogus readings) An AC impedance meter is more or less immune to introduced DC offsets and relatively cheap (Multimeters are great tools but it's important to understand their limitations)
This is a good one PH,,, 👍 love the can issues. I would reconnect the ebcm and go back to the bcm connector and ohm test the upstream wires like you talked about doing. Still haven't ruled out bcm. I suspect bad bcm,
This is exactly why all networks should have a common point to test like a star connector. Putting them all in series just makes it unnecessarily complicated under certain failure conditions. Had a couple of recent communication issues on Chrysler vehicles and as much as I hate Chrysler both of those cars had breakouts at the star connectors and both were diagnosed in a matter of minutes. It doesn’t help matters much that in this situation you now have a shady crimp job and an aftermarket Tesla screen in the mix on the network.
In order to have a star topology, they'd have to install a network hub to connect things together. (Extra $). The reason they run it in series is a high speed signal will run though the network until it's absorbed by the terminator. Connecting things as a star would cause too many reflections unless you really lowered the network speed, or used a active hub.
volkswagen did that quite a while back, but they bury the "switch"(gateway control module) deep in the dash. it's possible for one "port" to go bad making a single item go offline and anything else bad you can think of. also audi did and there was some lawsuit and major failures. go figure!
@@russellhltn1396 Mercedes do run their CAN systems via a pluggable star point which has diagnostic benefits. Many VAG and BMW are starred out via splices within the loom. However, the linear network style is generally better for signal integrity
Oh man! Beanie buttons notorious for high resistance opens. I made a boat load of $$$ removing them off copper lines for Ma Bell. Ruthless on DSL circuits
As a telecom Tech you cannot measure resistance if theirs any residual voltage on the cable what you could do is short cct one one end check the the integrity of the cable along the way .
Disconnect the battery if modules voltages affect the reading. You are middle of the network and one side is solid, other is not. The next good strategy is cut the network even smaller. I am not 100% sure but looks like failing transceiver inside some module. Leaks voltage and messing the resistance, interesting. Corrosion, it can not mess these numbers so high. Open wire, possible... Network smaller and it helps to narrow the problem
My first thought was a strange one, What size are the owners feet. I've seen before that sometimes you can clip connectors (or computers as possible here) when either getting in or out or during driving. That can cause all sorts of strange things. It got less likely as the video progressed but still worth a thought maybe.
That can happen. My wife had a friend who had a Toyota Matrix. She was hopeless and helpless about cars. She was having a problem where the carpet in front of the front passenger seat was wet. She had taken it to the dealer and their response was "They are all like that. Nothing can be done to fix it." Then she brought it to me. It was literally a 30 second fix. Her long legged daughter had kicked the AC evaporator condensate drain hose loose from the grommet in the floor so it was draining onto the carpet! I wish they were all that simple!
@@Vincent_Sullivan it happened with my old car, the guy who collected it for me took me out for 10 minutes in the car and during the drive the dash started lighting up like a Christmas tree. Turns out in my boots I had kicked a connector without noticing and the bcm was half unplugged.
I would do a voltage measurement from each CAN line to ground and batt+ and not just a differential voltage between the two CAN lines. Or, disconnect battery and do your resistance checks all over again. Or both. That randomly fluctuating resistance measurement really does seem like stray voltage and not something that a regular resistor or wiring could do all by itself. You could also maybe consider trying to run a little current through those CAN wires to see what kind of circuit integrity you really have.
Do all bus resistance checks with the battery disconnected and with no more than one ohm meter. This will rule out wire integrity problems and it might point you to the faulting module. Reconnect the battery. Interrupt the bus somewhere in the middle. Connect to one of the ends: a 120 ohm resistor, a scope and your scantool. Key on. Check if the bus is healthy and if you can talk to all modules on the leg under test. Do the same in the other direction. Remove and bypass suspected faulty modules. Restore the bus and keep suspected faulty module bypassed and test again. Of course without the extra resistor, when testing the restored bus. The splice with those wirenuts and blue splicer-things shouldn't be there to begin with. A better solution have been to de-pin from the broken connector housing and re-pin into the replacement connector housing. This repair job as is, will probably fail prematurely. It should be replaced with soldered and heatshrinked joints, and properly wrapped, to give it some protection against vibrations and the elements. (My edit: I corrected my resistor value. It needs to be 120 Ohm, just like the termination in the last module. Not 60 Ohm. My bad. Sorry.)
That wiring “repair” isn’t all bad, it’s just a matter of perspective. I chose to look at it as an “anti-theft deterrent”, designed to ensure that any would be car thieves up in NY don’t get too far.
Falling down that VOM rabbit hole. Yeah, check the comm wires for voltage, if no voltage found, reverse your leads on your meter...if resistance changes then you may be measuring a module internals and not a load resistor. You can also verify your ohm meter by measuring your decade box...your VOM battery could be low.
I’d go from the ecm and measure the wiring harness wires before suspecting failed modules. Usually the connections in the modules are just direct connections on the circuit board. If you find a bad module it is probably just a cold solider joint or corrosion on the pcb.
Hi Ivan, I would probably disconnect the battery just to see what the exact resistance is without any noise on it. Good video, looking forward to what you find in the next part of the video. Thanks Jordan
I read a few years back that an engineer or a group were trying to get a patent on a system that uses smaller simpler modules at every accessory location with just a power and ground at each with one fiber optic communication line connected to everything then back to one vehicle computer
i would yank out the connectors of all modules, so i could do a resistance test on each module. Check for water or green death as well. (Yes i havnt a clue lol)
I re-watched the video when you disconnected the blue BCM plug and stated that the reading should be infinity across the tan wires. It measured 4.5Kohms. That is not infinity. Other posters mentioned disconnecting the battery because of residual voltages. (i.e. leakage between pins on the connector(s)) That would make perfect sense as you noted when you paralleled the other ohm meter with the existing meter and measured different "ohm" readings. I believe that you still have connector issues. Also the crimps used at the EBCM are definitely not weather resistant, they are for use in dry locations only.
17:30 I'm looking right at that ground connection in the background an thinking that if any of those grounds for modules in the front or rear of the CAN bus goes bad it could cause strange readings when measuring the termination on that CAN network. The added resistance to ground adds into the termination resistance...
Those b connectors are not good on a car with the potential for water.. corrosion awaits, then failure. while they have gel in them the tips are exposed.
Electronics freeze spray can be worth it's weight in gold with intermittents. Little to no physical disturbance on suspect area but effective especially while monitoring with scope or meter.
i wouldn't do any other test before making sure that all those splices are top reliable. So, possibly redo them to the highest standard possible. Then do some more testing. If still needed.
A1 DIAGNOSTIC MOST LOGICAL EVER BETTER THAN THE DEALER. ERIC YOUR SCHOOLING BACKGROUND SET YOU TO LOCATE THE RUBBING ON WIRINGS LOOM BY THE TRANSMISSION. ERIC GOOD FOR YOU.
Disconnect the vehicle battery. use a 1.5volt battery on the can to test resistance with an amp meter. Section by section. Sometimes you need a bigger load to find a fault.
Former telephone splicer here.
First, you need to shunt the network at the ebcm back to the bcm. Verify that you have a solid 0 ohms (or close to that; temperature, wire gauge, and length of wire will determine the exact value). My guess is that you won't have 100% continuity. Additionally, I'd disconnect the battery to ensure that you don't have any stray voltage. I believe that you will find a spot where the insulation is nicked across that set of network wires, causing a partial open and short. I used to see this quite often is outside plant cables. You'd have a few wires losing insulation and damp, so the wires would corrode, starting adding resistance in series AND IN parallel. Additionally, sometimes, the circuit would be open from one end and have a high resistance short from the other. You could also get crossed with battery from another circuit (that generally wouldn't happen in a car if you disconnected the battery but..). Good luck, interesting problem to solve. Crawling around a car beats tracking down a problem in an 8 mile telco loop.
Also, get rid of those blue connectors. They are junk. They used to come in white and had "dolphin" stamped on the side. JUNK, with or without gel.
@@douglasjreynolds THAT IS A MESS FOR SURE.
@douglasreynolds Just a quick question if I may, what do you mean by shunt the network? Im curios thanks. I have more of a suspicion that the induced voltage will be something feeding back from the screen installed since last repair.
Agree. First disconnect battery and test wire integrity. Even when asleep some circuits have a minor current through them.
@@garryrussell7618 by shunt, I mean take a jumper and short the network wires going to the BCM together. Then, you can measure the continuity from the BCM connector to see if there is a break in the wire.
Ivan, you should build a detached garage and make it tall enough inside to put a two post lift inside and with plenty of space around for your tools, etc.
When I had my new house built I had the garage built with the ceiling at 12 feet high to have room for a lift when I'm ready for it.
You don’t want to use those skeevy crimps under a car. And GM should be spanked for putting an electronic module down there. They are doing this all the time. The Corvette also has a computer way down there. Water always wins.
Gm only has to consider those that live above the road salt line. Every one else is fine. No sense owning anything in new york more than 5 years
What type of location for electronics, a foot off the ground, behind the tire, out in the open.
Both statements I go with 100%. Exactly I had the same thoughts.
they don't want cars to last, they want to sell you a new one
Now we just need a rating system for auto manufacturers.
as soon as I saw those splicing beans, my stomach sank. those are made for security alarm work, not high speed, 5 volt data lines. then I saw the yellow wire nuts !! time to teach Jason how to solder and heat shrink
Same 😂
Ridiculous! The yellow ones look like wire nuts for house wiring. If this turd was in my bay, new harness or get it out of here.
Ugh..broken tabs on a connector? just plastic tie wrap it secure.. even rubber bands would have been better
Yep. Saw the yellow wire nuts and I’m done watching: it’s obvious where at least one of the problems lies.
he could just buy a cheap set of terminal extractor and swap the connector. the repair he made is garbage
Those wire crimps are going to become a problem very soon!
They're a nightmare.
Agreed......Surprised that Ivan gave him a compliment....
@@alleycatvietnam Bit awkward to tell a customer he's made a dogs dinner of the job 🤣
@@alleycatvietnam hah well they were tight and supposedly weatherproof... Wouldn't win a beauty contest though 😂
@@ferrumignis I agree.
Disconnect the battery when you measure ohms, eliminate another variable as there are always alive connections to the modules.
Get a OE pigtail for that and properly do those splices. The person that did that should not touch a vehicle electronic system ever again. Could of at least used the Solder sleeves. I would be wanting to fix that correctly first then chase the issue if it remains due to knowing its a issue.
yeah, no kidding, wtf is that garbage? I'd be ashamed to call that a "repair" - my god!
Exactly. It's no wonder something is going wrong with the Escalade hacked together like that... 🥺
Don't be too hard on the guy, he clearly just doesn't know how to do it properly. He needs to learn, not "never touch it again".
Everyone starts somewhere. Get off your high horse
@@mastahc411 No what was done on that is just being lazy to take time to do it right and spend a little bit to have it properly done. Fact is there is shops that do this crap and sell it to customers and the customer always loses in the end. And you definitely don't practice on a safety related system like the ABS. Be honest with yourself when doing a repair and if its above your skill level pay to have it done properly by a trusted source whoever that may be. There is one thing in trying to learn and quite another just not wanting to take the time to do it correctly. Someone that was just learning would of used unsealed butt connectors which they would of done a bit of reseach to find and not freaking household wiring nuts. This day and age information on this type of repair is easily found. Nobody is perfect but the ones that are willing to put in the effort are going to seek out the answers on how something should be done and deciding if they are capable or willing to do.
Disconnect the battery. Use only one meter at a time (you are reading the input stage of the other meter). Solder and heatshrink all those wire nut connections so you know they are good (needs to be done anyway). Measure each wire individually: connect one side of the meter to CAN high at the DLC, and the other side to CAN high at the EBCM, etc. Backprobe the BCM so you can also measure there with the BCM plugged in. There seems to be a lot of confusion here about what measurements are covering what, and that is what needs to be cleared up first.
This is literally the stuff of my nightmares--I'm driving my Avalon, then lights I've never even seen before start coming on, it starts falling on its face, making weird noises, etc. I wake up, realize it was a dream, and then remember I have Ivan to help me if that happens in real life 😅
It's a Toyota. Fear not. 😂
Wire nuts and jelly beans on the connecter can you imagine what it looks like behind that radio display.. I would run far far away very fast.
As Steven Lavimoniere would say "it's a shit show momma - what a f'ing shit show".
I bet the stupid Tesla screen is causing all of that.
This one has got me intrigued.
I have no interest in cars. I found this channel as I was searching for a soldering iron, and now I'm hooked. For me, it's about troubleshooting complex systems. Just watching Ivan, and his refined technique, has made me a much better systems troubleshooter, for both hardware and software!
I've never worked on an auto computer network but as a maintenance engineer (retired) I've troubleshot numerous industrial systems. Ivan has the guts to show you his whole technique on video, including the dead-ends. He's a great example and teacher.
WELLER WX series is my favorite for microsoldering 😁👍
I apologize if this has already been mentioned, but an easy way to validate an ohm reading is to reverse the leads at the meter. If the reading is different, there is a problem.
Hi Ivan, I'm not sure if it's part of the problem or not but you need to fix those splices. There's electrical wire nuts on some of them! Not to mention they're on the underside of the car exposed to all sorts of water and water spray. I would trust those connectors about as far as I could throw that Escalade! I don't know if you can get a new connector or not but at the minimum those splices need to be redone and watertight! I'm also not thrilled with the resistance changing depending on the position of the connector bail. I'd fix that whole connector and splice mess before going any further just to eliminate it as being the issue or contributing to it. Thanks as always for another great video, it's fun to watch your logic. I will say you don't cuss nearly as much as I would!
You should NEVER do ohms measurements on live circuits, even if they are in sleep mode.
Even any "yawning" data in the circuit will instantly flip the ohms measurement.
You MUST decide your method :
a) Have the circuit live and do voltage/data measurements
or
b) Have the battery disconnected and do continuity / ohms measurements
You can NOT do both reliably !
So ironic. I had an Escalade do the exact same thing this week. It ended being the radio. The class 2 serial data message coming from the radio was 0 to 13.5 volts instead of 0 to 7. Fixed that. Then every once in a while you go start driving and the stability light would come on and you lose throttle response for a few seconds. Turned out to be the steering angle sensor. It was jumping around from 0 degrees to 162. And when turning left it jump from -220 to 510. Crazy.
Very interesting. I would only say that I would check the resistance with the BOB unplugged. The BOB can interfere with the CAN network on some vehicles, especially if a Scan tool is connected to it. One way it can do this is that it can act like an antenna hanging off the CAN bus. Some Scan tools connected to a BOB on some cars will not even connect, but will connect fine without the BOB. Depends, of course, on the particular BOB as well.
This has nothing to do with the root cause of the problem however, but may have something to do with the resistance jumping all over the place. If not, it seems it would most likely be a poor connection somewhere on the CAN bus. I am trying to go by memory here as I don't have a lot of time to re-watch the video right now, but I think which ever CAN line was connected to channel two (Red), was worse than the other. I may be mistaken here though.
Once again, very interesting, and thank you for making these videos. They are appreciated.
Those connections might be a problem in the near future.
Not might, it will be!!!. those splice need to be Repaired properly.
what gave u that crazy idea 🤣
Many of those “Tesla style” radios tap into the network, could be a new problem introduced. The wire nuts on the ebcm aren’t too encouraging even if the resistance appeared stable while messing with the connections.
Good point
Just the word Tesla should strike fear into anyone.
It might help when doing your resistance tests to disconnect battery so as not to worry about networks awaking and sleeping
100%
i bet ivans heart sank when he saw those twist connectors
A bit yes 😅
What a beautiful boat anchor.
I would start with redoing that pigtail. That looks super sketchy. Make sure you can trust it before you start chasing your tail.
I'd see if that aftermarket Tesla screen/radio is part of the BCM .
Since it's aftermarket it might have one of those com boxes to make it work and those always cause problems.
No they don't....if you use the correct one and its done professionally
That wiring is next level ghetto rigged
Haha
Not everything that CAN be fixed SHOULD be fixed. RUN away from those wire nut and shady connections! I would insists on a new wiring harness or not repair it, or it WILL be back!
I agree
Could not agree more.....OMG....its a nightmare ...just wait until the grenade goes OFF
Thanks for showing this case Ivan ,helps me understand a little bit better the complicated process,.
You have me on the edge of my seat for part 2
I don't know if it will influence something, but the first thing I would do is reattach the connector your way to get rid of that variable. If it quacks like crap, it will behave like crap. Maybe the customer does not want to incur the additional cost of getting the connector reattached correctly. In that case he will have to understand the risk he takes.
You question the dealer, that is a very good question. Dealers are usually only interested in shooting their own parts cannon :)
I wonder if that aftermarket Infotainment Center is causing this?
That huge screen in the middle that replaced the Radio head unit and the hvac controls.
That's on the single wire low speed network 😉
It makes me wonder why the BCM was replaced before. I wonder if there's a windshield leak, or maybe the rubber gromet near the door hinges- and there's somehow getting water dripping on the BCM, and that's why there's yet another BCM failure (if that's even the problem).
I think you know that you can't put two ohm meters in parallel, but also for consistency of testing, you should use the SAME meter at each test point.
Crusty faults are non-linear (IE not a pure resistance) so the testing voltage of the meter will influence the reading.
This test voltage can typically vary between 0.5V and 5V on digital meters.
Wire-nuts and Bennies! Yikes! That will never be a reliable fix!
My brain was hurting just watching you Ivan.
Initially, the resistance reading of the network was about 40 ohms too high, then it continued to climb. I suspect a corroded, high-resistance wire between the VCIM and the EBCM. To confirm, I'd isolate the VCIM and EBCM by unplugging them and use an incandescent test light to load the communication wires between the two modules. In other words, I'd use the test lamp as a continuity tester and use the communication wires as the jumper wire to complete the circuit. The circuit will likely only see 8mA of current during normal use, so I'd want to stress test the wires by ensuring they can carry at least 250mA.
I would bypass the can wires going to the bcm and plug everything back and see what happens to the ohm readings, or check for any "added" power gps or alarms that maybe tied into the Bcm..
There has been times that I contemplated yanking the whole harness in a car, and rewire it with a universal hot rod harness and ditch the computers. But your knocking off the problems on this one a wire at a time. Would be good training for other automotive techs. 👍🏻👍🏻
Creepy déjà vu! Not sure if it's easy, but I would have started in the 120 Ohm resistor to set a baseline, and go back measuring through each module (maybe also reversing the leads to compare - if there's a parasitic voltage, there could be a module leaking irregularly in sleep mode). Very curious of what Part 2 will bring.
You can test to see if a voltage is affecting the DVM reading by switching the DVM leads (polarity). If the reading is different with the leads switched, then a voltage is throwing you off. And for testing purposes, you might need to disconnect the vehicle's battery until you have the resistance measurements sorted out. If the resistances are OK with the battery disconnected, then it looks like a bad module may be the cause - and you're way above my skill level (I use the term "skill" very loosely). I can't wait to see part 2!
Good stuff Ivan.... cut the net in 1/2... 1/2 good 1/2 not .... so cutting the bcm out of the loop and the other 1/2 of net's good? then bcm for sure? .. thanks for sharing your time.
sorry man.... just noticed this is a year ago... ha ha... I've already watched the answers in part 2.... duh.
yeah.... miles off in fact
An ohm reading that starts at 0 or very low and then climbs can indicate a capacitor in a circuit. There may be one of the can lines is open at some point... That's from my electronics past...
It’s bazaar that this kind of crazy stuff that makes modern cars a real pain to own
Need to do wiring repair at the ABS module. Clean, tight connections are a must on low voltage circuits. I think either a bad connection at a module or a possible corroded wire that hasn't broken all the way through yet.
Great Video!! Having very similar problem on 2008 Caddie CTS. Where are you finding the network wiring diagrams for the Caddie??
Sorry Ivan. Resistance is futile. I had a 2008 same model. Loved that truck more than life. Never let me down.
The fact is Cadillac has had engineering build quality issues for a very long time, from the 70's to my knowledge
In my opinion, having electronic modules with an exposed main connector underneath the vehicle sold and operated in the rust belt is just crazy. This module should be in the vehicle and not under it. Add to this the connector swap with all the splices, again exposed underneath the vehicle, I feel is not reliable. You would have to somehow seal the module and the harness so they are not exposed to water (or hold water) and salt spray.
I would have removed the module and inspected and cleaned the module pins on the bench. For inspection on the bench I use an electronic repair type stereo microscope.
If the module pins are heavily oxidized use Deoxit D5 spray to rinse and clean the harness and the module connector. Then apply Deoxit D100 with needle applicator and mate the two. Then disconnect and mate again. If you do several mating cycles (like 4 or 5) the Deoxit D5 + D100 will start to breakdown all of the oxidation and provide a noticeable lubrication, meaning the connection will feel easier to seat. When the pins mate smooth and easy you know they are clean. In my experience, the 4 or 5 connector cycles used in this cleaning process will not effect pin tension. You can try this yourself on the bench if you have some old oxidized machine barrel pins, like Deutsch DTM series pins, and apply Deoxit (use D100 with the needle applicator) and do some mating cycles with a single pin connection and you will notice the pin connection wiping action cleaning and lubricating the connection. The old oxidized pins will be cleaned completely with the repeated mating and mate easier.
Have had soo many issues with inexpensive meters. Have Fluke 87v and 88. And the bluepoint. Always stable.
If there's anything still live on the CAN and adding voltages outside of the meter you'll get "off" resistances (ie, bogus readings)
An AC impedance meter is more or less immune to introduced DC offsets and relatively cheap
(Multimeters are great tools but it's important to understand their limitations)
Is part 2 ready yet?
Hahaha wire nuts. Unbelievable. That's a I'm fixing this my way, or I can't keep going.
I am really confused. Ivan needs to get a back bone and explain the facts of life to this gentleman. It would be my way or the highway!
A GM with a wiring problem?..never..LOL🤪🇨🇦
Bought a tesla screen from Phoenix. It was the biggest mistake ever
This is a good one PH,,, 👍 love the can issues. I would reconnect the ebcm and go back to the bcm connector and ohm test the upstream wires like you talked about doing. Still haven't ruled out bcm. I suspect bad bcm,
Great videos....do u sell a diagnostic book by chance ??? And if so how do I get it ???
This is exactly why all networks should have a common point to test like a star connector. Putting them all in series just makes it unnecessarily complicated under certain failure conditions. Had a couple of recent communication issues on Chrysler vehicles and as much as I hate Chrysler both of those cars had breakouts at the star connectors and both were diagnosed in a matter of minutes. It doesn’t help matters much that in this situation you now have a shady crimp job and an aftermarket Tesla screen in the mix on the network.
In order to have a star topology, they'd have to install a network hub to connect things together. (Extra $). The reason they run it in series is a high speed signal will run though the network until it's absorbed by the terminator. Connecting things as a star would cause too many reflections unless you really lowered the network speed, or used a active hub.
volkswagen did that quite a while back, but they bury the "switch"(gateway control module) deep in the dash. it's possible for one "port" to go bad making a single item go offline and anything else bad you can think of.
also audi did and there was some lawsuit and major failures. go figure!
If you go to a star topology you start increasing the amount of wiring.
@@ferrumignis not by much...
@@russellhltn1396 Mercedes do run their CAN systems via a pluggable star point which has diagnostic benefits.
Many VAG and BMW are starred out via splices within the loom.
However, the linear network style is generally better for signal integrity
How about disconnecting the car battery before doing resistance measurements?
Oh man! Beanie buttons notorious for high resistance opens. I made a boat load of $$$ removing them off copper lines for Ma Bell. Ruthless on DSL circuits
Dam. Dsl day nightmares. Thanks.
As a telecom Tech you cannot measure resistance if theirs any residual voltage on the cable what you could do is short cct one one end check the the integrity of the cable along the way .
Get the soldering Iron,solder,and flux paste out.
I would be afraid to do more than offer the guy a cup of coffee and condolences. How can you warranty work connected to that bed of roses?
No coffee. It would be a waste of good coffee. If the owner accepts such shady tree mechanics fixes, "no soup for you". (Seinfeld soup guy)
Disconnect the battery if modules voltages affect the reading. You are middle of the network and one side is solid, other is not. The next good strategy is cut the network even smaller. I am not 100% sure but looks like failing transceiver inside some module. Leaks voltage and messing the resistance, interesting. Corrosion, it can not mess these numbers so high. Open wire, possible... Network smaller and it helps to narrow the problem
My first thought was a strange one, What size are the owners feet. I've seen before that sometimes you can clip connectors (or computers as possible here) when either getting in or out or during driving. That can cause all sorts of strange things.
It got less likely as the video progressed but still worth a thought maybe.
That can happen. My wife had a friend who had a Toyota Matrix. She was hopeless and helpless about cars. She was having a problem where the carpet in front of the front passenger seat was wet. She had taken it to the dealer and their response was "They are all like that. Nothing can be done to fix it." Then she brought it to me. It was literally a 30 second fix. Her long legged daughter had kicked the AC evaporator condensate drain hose loose from the grommet in the floor so it was draining onto the carpet! I wish they were all that simple!
@@Vincent_Sullivan it happened with my old car, the guy who collected it for me took me out for 10 minutes in the car and during the drive the dash started lighting up like a Christmas tree.
Turns out in my boots I had kicked a connector without noticing and the bcm was half unplugged.
We called stuff like that "Hangar Queen" or "Depot Queen." for what you call "Parts Cannon." LoL!
Ivan at 26:25 mark, if the ebcm and bcm were both unplugged, shouldn’t the resistance be OL? Why is it showing 4k ohms?
I would do a voltage measurement from each CAN line to ground and batt+ and not just a differential voltage between the two CAN lines. Or, disconnect battery and do your resistance checks all over again. Or both. That randomly fluctuating resistance measurement really does seem like stray voltage and not something that a regular resistor or wiring could do all by itself. You could also maybe consider trying to run a little current through those CAN wires to see what kind of circuit integrity you really have.
Do all bus resistance checks with the battery disconnected and with no more than one ohm meter. This will rule out wire integrity problems and it might point you to the faulting module. Reconnect the battery. Interrupt the bus somewhere in the middle. Connect to one of the ends: a 120 ohm resistor, a scope and your scantool. Key on. Check if the bus is healthy and if you can talk to all modules on the leg under test. Do the same in the other direction. Remove and bypass suspected faulty modules. Restore the bus and keep suspected faulty module bypassed and test again. Of course without the extra resistor, when testing the restored bus.
The splice with those wirenuts and blue splicer-things shouldn't be there to begin with. A better solution have been to de-pin from the broken connector housing and re-pin into the replacement connector housing. This repair job as is, will probably fail prematurely. It should be replaced with soldered and heatshrinked joints, and properly wrapped, to give it some protection against vibrations and the elements.
(My edit: I corrected my resistor value. It needs to be 120 Ohm, just like the termination in the last module. Not 60 Ohm. My bad. Sorry.)
You have at least an open in the CAN circuit to one resistor, AND something is also mis-wired!
It's in that menagerie of a wiring job!
That wiring “repair” isn’t all bad, it’s just a matter of perspective. I chose to look at it as an “anti-theft deterrent”, designed to ensure that any would be car thieves up in NY don’t get too far.
Falling down that VOM rabbit hole. Yeah, check the comm wires for voltage, if no voltage found, reverse your leads on your meter...if resistance changes then you may be measuring a module internals and not a load resistor.
You can also verify your ohm meter by measuring your decade box...your VOM battery could be low.
I’d go from the ecm and measure the wiring harness wires before suspecting failed modules. Usually the connections in the modules are just direct connections on the circuit board. If you find a bad module it is probably just a cold solider joint or corrosion on the pcb.
Hi Ivan, I would probably disconnect the battery just to see what the exact resistance is without any noise on it. Good video, looking forward to what you find in the next part of the video. Thanks Jordan
do you do "pin pull" tests on connectors?
Is the voltage effecting the resistance or is the resistance effecting the voltage? Disconnect the battery and eliminate that variable.
I read a few years back that an engineer or a group were trying to get a patent on a system that uses smaller simpler modules at every accessory location with just a power and ground at each with one fiber optic communication line connected to everything then back to one vehicle computer
I did not realize at first the connection was outs in the rain/water 💦 to be guaranteed to fail
I would perform resistance testing with battery disconnected and go from there. DC offsets will mess up your resistance readings.
Meter “jumps around” this car’s a whole House of Pain :)
i would yank out the connectors of all modules, so i could do a resistance test on each module.
Check for water or green death as well. (Yes i havnt a clue lol)
Bad solder joint on the ABS control module.
I believe the Escalades have a lot of tech bulletins for network issues but I’m not sure if this truck is of the vintage with those issues
I re-watched the video when you disconnected the blue BCM plug and stated that the reading should be infinity across the tan wires. It measured 4.5Kohms. That is not infinity. Other posters mentioned disconnecting the battery because of residual voltages. (i.e. leakage between pins on the connector(s)) That would make perfect sense as you noted when you paralleled the other ohm meter with the existing meter and measured different "ohm" readings. I believe that you still have connector issues. Also the crimps used at the EBCM are definitely not weather resistant, they are for use in dry locations only.
Maybe the added weight from all the wire nuts and b connectors made the connection come apart?
So work has been done to vehicle after you fixed it and now the problem returns?
Thanks Ivan!
A thermally timed out dead headed servo maybe in ADAS or similar maybe coming back online during anomaly scope capture.
17:30 I'm looking right at that ground connection in the background an thinking that if any of those grounds for modules in the front or rear of the CAN bus goes bad it could cause strange readings when measuring the termination on that CAN network. The added resistance to ground adds into the termination resistance...
How does having the can network benefit the vehicle or the mechanic.
I like using Stabill on the data line terminals.
holly cluster F**k, I have used B connectors for years in the phone/ alarm business, not to be used outdoor, Run like hell
If they were replacing the plastic connector because of a broken tab, I wonder why they didn't just depin and put pins in the new connector.
Those b connectors are not good on a car with the potential for water.. corrosion awaits, then failure. while they have gel in them the tips are exposed.
Electronics freeze spray can be worth it's weight in gold with intermittents. Little to no physical disturbance on suspect area but effective especially while monitoring with scope or meter.
Bernie would say this is one crazy car
Dude jumped out of the truck like he has warrants.
Tell Jason to buy the wiring harness and get rid of that crap wire repair.
i wouldn't do any other test before making sure that all those splices are top reliable.
So, possibly redo them to the highest standard possible.
Then do some more testing. If still needed.
A1 DIAGNOSTIC MOST LOGICAL EVER BETTER THAN THE DEALER. ERIC YOUR SCHOOLING BACKGROUND SET YOU TO LOCATE THE RUBBING ON WIRINGS LOOM BY THE TRANSMISSION.
ERIC GOOD FOR YOU.
Why was splicing like that necessary? And he was going to drive that rats nest from New York to California? SMH
Ya think Eric would touch this one?
@@hikerJohn not in a million years. Get this junk ride outta here…
Disconnect the vehicle battery. use a 1.5volt battery on the can to test resistance with an amp meter. Section by section. Sometimes you need a bigger load to find a fault.
That is some bad crimps.....maybe a good soldering??
Tests for high short to ground?