@@fixingcarswith15thstautomo36 They sell a TR for this purpose but why buy that part when yours comes with a super nice kit already in hand. The rheostat can do a hundred experiments as well. OH, and by the way brother, pls mark your test light 3A if that is what it actually is, along with several other AMP DRAWS that we all ought to have on hand.
thanks for the video.... very surprised you are not using a small scope on the can lines.....that would actually speed up you testing.... after splitting the system in half the scope would have given you the direction of the issue....with a scope as soon as you unplugged the module you had issues with you would have known...again great video
I know what you are saying, but in this case and in the process that Steve used, he seems to not be fully trained in truly splitting, then resplitting the circuit as we are taught in electronics classes to at least cut out a couple of his tests, if we go past the problem then we know not to back up as far as the last good test so its narrowed down a little faster and when we get paid flat rate, we need speed. But here in RUclips land, I notice ALL providers take the slow route. If it was me, I would take the speed route, then go back for the DIY community to learn the expanded method, we could call it the fail-safe method. I have seen a very bad representation of the fail-safe method as it was a total failure on another popular channel that I will not mention as the guy is an electronics module repair person but cannot explain a fuse box to save his life, OMG.
The term GATEWAY typically refers to the meeting point of different COMM protocols, CANC, CANB, CANA, LIN, GMHS, KLINE, etc, and the GATEWAY translates these different protocols so the GATEWAY can include needed packet data to the others. In your schematic, the BCM is simply doing what GM does, CAN COMM in on 2 wires and back out on 2 other wires, in this case, on 2 different connectors, good for bypassing the entire module as one of your old UXXXX videos showed. Now in the real world, there may be other protocols going to the BCM but it's not apparent on this diagram, hence my comment that we cannot call the BCM a GATEWAY just yet, and that is a problem on schematics around the world. Many times a wire that is on this diagram spices off to another system with no hint of that splice and an arrow or some designator leading us to a different diagram, very sad in the 21st century. Your TOPOLOGY shows the BCM as a type of GATEWAY along with 5 other modules, are they actually translating GATEWAYS of just talking on 2 different protocols, that is the question. The good thing is they are not SECURE GATEWAYS like 2018+ CHRY and some EURO models creating parts cannons as many techs don't understand how to test a SGW attached directly to the DLC. DONT TEST AT THE DLC... Just watched a video last week of a Dodge Challenger/Charger where the TOPOLOGY showed the BCM as a GATEWAY for CANPT and Interior CAN but FORGOT to draw the CANPT going to the Radio (but later found the schematic was correct) and almost every module in the car was dead on both protocols. How often is a bad radio at the top of our list for checking, if we knew it was on both sides of the house, OMG.
Thank you for showing yet another problem with TOPOLOGY, not telling the truth that a module is communicating but cannot be read. Now we need to spend time to rescan 2 or 3 times. I can appreciate the training that you gave by going from module to module but in the real electronics field, we split the problem area in half, the TCM was ok, and the full circuit harness was good, so going past the next module between the PSCM and the ECM was the next logical step then backtrack if needed. In this case that would have been the only test to say the ECM is the problem based on the good TCM to the DLC as all COMMs passed through each presumed dead module via the CAN IC that also must have power and ground to those modules for this to happen is the only reason I would have started there based on the data in front of us. Diagnosing CAN starts with a schematic as the TOPOLOGY never shows proper series and parallel of modules in relation to each other nor the backbone, that is one CON of TOPOLOGY, thanks for everything.
The backbone was still good end to end, hence the 61 ohms, remember as the rheostat was being moved, there was a spot with 72 ohms, I have seen ONE repair manual with 72 as the upper limit. All modules had power and ground, all modules had a good backbone, not all modules could communicate but they could pass thru the TCM to the DLC and maybe the bad packets seen later in the day was the TCM?? on the scope. Need to do a little research on CAN ICs, none of them were dead but the ECM was corrupt. This is one reason why there is a low side and a high side, redundancy for major malfunctions.
Mr I having problems with my 2013 GMC Yukon is not communicating with ECU or TCM. I have 120 ohms and replaced ECM AND TCM BCM and still not reading Vin number I put all original parts back All the rest of modules communicating fine with codes lost communication with ECM AND TCM in the cluster is not showing in wich gear is it truck won't crank no start traction control light on if you can help please
rheostats have 3 wires, end to end of the entire resistor, lets say 1000 ohms, put the center wire on the wiper and run the wiper to the middle of the rheostat, you get 500 ohms out of the center wire if the rheostat is wound evenly, normally not, run it back half way again, you split the full resistor 25 : 75 or 250 on one set of wires and 750 on the other set of wires. If this scenario was true, your rheostat would give 120 ohms on one side and 880 ohms on the other side. What ever the full resistance is, just split it up as a ratio of 100% such as 120 : 880 or 12% : 88%, hope that helps. Not all rheostats are wound evenly across from end to end.
Many vehicles will still drive with one of the ECM powers down, blown fuse, bad relay, but of course a low level use portion of the ECM such as in this case, full COMM is not always needed these days.
When identified of the problem, go back a year or even 2 to find the correct diagram, hopefully. In this case, the wire colors were known and correct, there was a 50/50 chance of stabbing the resistor into the proper pins, and in less than 60 seconds the correct set would have been found, I would not even tried to find the correct diagram. But Steve is overloaded with energy, so I get it.
@@fixingcarswith15thstautomo36 that is why we need to do our documentation in a format like Word or a format tied with GRAMMERLY, also how many times have we lost power, something crazy with a laptop/PC Crash and lost ALL of our documentation. Set up Word to backup every so often, auto spell correction and transfer the info when verified and most will be saved in worse case crash scenario and we have a backup for another purpose such as creating a lesson plan, or melding 20 COMM repairs into a chapter of a book now that AI can write the book for us based on the 20 documents that we feed it, etc, etc. Years ago I captured my canned answers for the Forums, copy and paste, and edit them as more information was gathered. Folks on the Forum wondered where in the hell did I get all this information in my head, its not in my head, its in my DATABASE from different formats of MS Office.
That was a neat technique you used to find the bad module. I have that same kit and variable resister so I will have to keep this test method in mind.
Glad it was helpful!
Thanks for sharing this! I’ve never thought about moving a 120 K resistor down the line like.
Neither had I. I just thought I would try it.
@@fixingcarswith15thstautomo36 They sell a TR for this purpose but why buy that part when yours comes with a super nice kit already in hand. The rheostat can do a hundred experiments as well. OH, and by the way brother, pls mark your test light 3A if that is what it actually is, along with several other AMP DRAWS that we all ought to have on hand.
thanks for the video.... very surprised you are not using a small scope on the can lines.....that would actually speed up you testing.... after splitting the system in half the scope would have given you the direction of the issue....with a scope as soon as you unplugged the module you had issues with you would have known...again great video
I know what you are saying, but in this case and in the process that Steve used, he seems to not be fully trained in truly splitting, then resplitting the circuit as we are taught in electronics classes to at least cut out a couple of his tests, if we go past the problem then we know not to back up as far as the last good test so its narrowed down a little faster and when we get paid flat rate, we need speed. But here in RUclips land, I notice ALL providers take the slow route. If it was me, I would take the speed route, then go back for the DIY community to learn the expanded method, we could call it the fail-safe method. I have seen a very bad representation of the fail-safe method as it was a total failure on another popular channel that I will not mention as the guy is an electronics module repair person but cannot explain a fuse box to save his life, OMG.
Great work you do there at 15th St Automotive !! ☝👍👌🙂
Thanks 👍
Great video.! As always, very informative.! Thanks again.!
Fantastic video ad explanation
Whoa! Is this Jaded Mechanic Jeff Compton? Thanks for the kind words!
28 seconds into this video and it sounds like a loose ground cable at the battery terminal.
The term GATEWAY typically refers to the meeting point of different COMM protocols, CANC, CANB, CANA, LIN, GMHS, KLINE, etc, and the GATEWAY translates these different protocols so the GATEWAY can include needed packet data to the others. In your schematic, the BCM is simply doing what GM does, CAN COMM in on 2 wires and back out on 2 other wires, in this case, on 2 different connectors, good for bypassing the entire module as one of your old UXXXX videos showed. Now in the real world, there may be other protocols going to the BCM but it's not apparent on this diagram, hence my comment that we cannot call the BCM a GATEWAY just yet, and that is a problem on schematics around the world. Many times a wire that is on this diagram spices off to another system with no hint of that splice and an arrow or some designator leading us to a different diagram, very sad in the 21st century. Your TOPOLOGY shows the BCM as a type of GATEWAY along with 5 other modules, are they actually translating GATEWAYS of just talking on 2 different protocols, that is the question. The good thing is they are not SECURE GATEWAYS like 2018+ CHRY and some EURO models creating parts cannons as many techs don't understand how to test a SGW attached directly to the DLC. DONT TEST AT THE DLC...
Just watched a video last week of a Dodge Challenger/Charger where the TOPOLOGY showed the BCM as a GATEWAY for CANPT and Interior CAN but FORGOT to draw the CANPT going to the Radio (but later found the schematic was correct) and almost every module in the car was dead on both protocols. How often is a bad radio at the top of our list for checking, if we knew it was on both sides of the house, OMG.
Thank you for showing yet another problem with TOPOLOGY, not telling the truth that a module is communicating but cannot be read. Now we need to spend time to rescan 2 or 3 times. I can appreciate the training that you gave by going from module to module but in the real electronics field, we split the problem area in half, the TCM was ok, and the full circuit harness was good, so going past the next module between the PSCM and the ECM was the next logical step then backtrack if needed. In this case that would have been the only test to say the ECM is the problem based on the good TCM to the DLC as all COMMs passed through each presumed dead module via the CAN IC that also must have power and ground to those modules for this to happen is the only reason I would have started there based on the data in front of us. Diagnosing CAN starts with a schematic as the TOPOLOGY never shows proper series and parallel of modules in relation to each other nor the backbone, that is one CON of TOPOLOGY, thanks for everything.
Great video
❤❤❤❤❤❤
How was the scan tool able to communicate at all?
The backbone was still good end to end, hence the 61 ohms, remember as the rheostat was being moved, there was a spot with 72 ohms, I have seen ONE repair manual with 72 as the upper limit. All modules had power and ground, all modules had a good backbone, not all modules could communicate but they could pass thru the TCM to the DLC and maybe the bad packets seen later in the day was the TCM?? on the scope. Need to do a little research on CAN ICs, none of them were dead but the ECM was corrupt. This is one reason why there is a low side and a high side, redundancy for major malfunctions.
@@DuaneDonaldson Thank you.
Mr I having problems with my 2013 GMC Yukon is not communicating with ECU or TCM. I have 120 ohms and replaced ECM AND TCM BCM and still not reading Vin number I put all original parts back All the rest of modules communicating fine with codes lost communication with ECM AND TCM in the cluster is not showing in wich gear is it truck won't crank no start traction control light on if you can help please
This is more of a job than can be diagnosed through the comments section. Sorry but it's not a job for DIY.
Can bus issues are always interesting
GM Combs and DAIMLER STAR Connectors really help out a lot. Other makers have same or similar junctions as well.
What about using a scope to see signal integrity?
I actually did that later in the day. The base voltage was at 3.6 volts and no discernible packets.
I forgot what year the Camaro is, but it is clean underneath. I watch other's videos and some work on rust-buckets.
We are in Washington and get very little rust. No salt on the roads and lots of fresh rain to rinse off most of the contaminants.
What is red wire on variable resister for, I hv same kit but doesn't say when to use red wire
To be honest I don’t know. I had to play with it for a minute to see which leads were used for the variable resistor.
@@fixingcarswith15thstautomo36 I had to as well, just curious what red wire may be used for thank u sir
The red wire splits resistance to another module when needed.
rheostats have 3 wires, end to end of the entire resistor, lets say 1000 ohms, put the center wire on the wiper and run the wiper to the middle of the rheostat, you get 500 ohms out of the center wire if the rheostat is wound evenly, normally not, run it back half way again, you split the full resistor 25 : 75 or 250 on one set of wires and 750 on the other set of wires. If this scenario was true, your rheostat would give 120 ohms on one side and 880 ohms on the other side. What ever the full resistance is, just split it up as a ratio of 100% such as 120 : 880 or 12% : 88%, hope that helps. Not all rheostats are wound evenly across from end to end.
If I ever have electrical issues with my car, I'm bringing it to you. I'm a DIY'er, except for electrical problems. Knock on wood.
On a can bus network the functioning modules can still communicate.
Many vehicles will still drive with one of the ECM powers down, blown fuse, bad relay, but of course a low level use portion of the ECM such as in this case, full COMM is not always needed these days.
Unacceptable that the alldata wiring diagram was wrong at the power steering module thereby wasting your time.
When identified of the problem, go back a year or even 2 to find the correct diagram, hopefully. In this case, the wire colors were known and correct, there was a 50/50 chance of stabbing the resistor into the proper pins, and in less than 60 seconds the correct set would have been found, I would not even tried to find the correct diagram. But Steve is overloaded with energy, so I get it.
Why can’t anybody spell Camaro correctly?
Hah! I had the video published before I caught that. I’m usually pretty good about catching mistakes like that.
@@fixingcarswith15thstautomo36 that is why we need to do our documentation in a format like Word or a format tied with GRAMMERLY, also how many times have we lost power, something crazy with a laptop/PC Crash and lost ALL of our documentation. Set up Word to backup every so often, auto spell correction and transfer the info when verified and most will be saved in worse case crash scenario and we have a backup for another purpose such as creating a lesson plan, or melding 20 COMM repairs into a chapter of a book now that AI can write the book for us based on the 20 documents that we feed it, etc, etc. Years ago I captured my canned answers for the Forums, copy and paste, and edit them as more information was gathered. Folks on the Forum wondered where in the hell did I get all this information in my head, its not in my head, its in my DATABASE from different formats of MS Office.