30 minute video saved me countless hours of diagnosis, hats off to you! What a great video and damn good mechanic, very few take the time you do, most would have wasted the $$ on a ecu and still be in the same boat!
Unbelievable skill and patience, I hope your customers appreciate you. Can't imagine a chevy garage solving this problem. Next time Space X has a wiring problem can they call you ?
H,iHaving the same thing with my 06 lbz classic..... going to check that bolt even tho im also not sure the ecm on mine is grounded there and my ecm is different than the lly. god i hope thats it..... You are the man. best and only vid of this clear and easy to follow step by step explanation.....n.. lots of others have had this problem and even with scsnners just started throwing parts t it... Im a good mechanic and have been wrenching since 1975 at 5 yrs old with my dad im 51 now,and this truck has been kicking my ass on this one... I have read and watched video after video on all other possibilties and all were other common issues fr these probs and nothing... The local port oregon dealers NO HELP AT ALL.......JUST BRING HER IN..... BS.......Thank you so much for posting this..... great stuff sir....... Thank you from portland oregon...
@@PhillipBailey Yes it do as i also had other and previous codes.... I can aslo clear them and if i jump the starter relay pins with a paper clip it will start and run and i can put the realy back in place but wont crank when i shut off and try to tr crank or restart.... im so confused.. my ecm seems to be working to some degree?? also still get p700 and u1001 ugh!!!!
@@sandimastodd P0700 is a generic code for the transmission controller requesting the ECM to illuminate the MIL. The U code could be your issue as that a communication error between modules. The TCM talks to the ECM of a high speed 2 wire can bus. Since the TCM tells the ECM if its in park or neutral if uts not able to communicate that the ECM won't energize the starter relay. Since you were able to get it running by bypassing the starter relay then you are correct in assuming the ECM is likely fine. Can you scan the TCM for codes. Have you tried driving it once its running does it shift normal. Check powers and grounds to the TCM. Hope this helps good luck
@@PhillipBailey I appreciate all the help.... Can you tell me the wire colors and pin locations and or numbers on the tec connector???? Let me know thank you. Im not real good with electrical scems....... Thanks again Todd.
@@sandimastodd All terminals at the TCM: Pin 63 pink wire from IGN 0 fuse in IP fuse box with ignition on, Pins 10 and 70 Orange wires from TCMB fuse in engine compartment fuse box hot all times, Pin 43 Purple Hot in crank position, Pins 9 and 59 Black/White both grounds at G102. Can you read codes and data from the TCM? Need a decent scan tool to access not just and OBD2 code scanner. Usually with a power or ground problem to the TCM there will be no communication with it. good luck
You did a great job. I am gonna check my 2004 Chevy 4500 ground wires. It was running fine and I shut it off at a friend's place. Went to move it and it would not crank. I got the code u0105 which is fuel injector module problem. I think it said no communication or something similar. I almost bet it is a ground wire. I ordered a new module and that didn't help so I am almost certain that the ground is the issue or the power wire is cut or frayed somewhere. Tume to go look and thanks for.the great video! It will hell me to not forget the ground wires
I have a question I have 6.6 duramax van 2006 g3500 and my van will start in the morning but after an half hour of driving all my dash lights go hay wire and then back to normal sometimes stay off .. after I stop I have have to wait at least half hour before it will start also sometimes I turn it off my key domes out but van stays running…… help
I have a 05 lly I have 30 tcm codes all electrical and the truck will go into reverse and drive but stuck in first gear will move about a foot then goes to neutral I've been tracing wires so far no luck I have power and ground to tcm and replaced tcm and ignition switch and changed fluid and filters which looked good any ideas?
Hey man, I got a 2003 lb7, my problem is when I start the truck it starts completely fine, but when I go to turn it off nothing happens. Truck still runs.. I have changed ingnition switch. When I changed the edu relay it went completely back to normal, after 30 minutes of driving the relay got hot and all the problems came back.
i got a 2007 GMC Sierra 6.6 diesel .. same problem .. no start and no communication . someone swapped out the engine and now it won't start .. tomorrow I'm going to check all the grounds ...
Pretty awesome Mr. Phillip Bailey. I have a 2011 LML Duramax. Back when it was a lot hotter, when my truck got very hot it would shut off and like on this video it wouldn't crank and the check engine light wouldn't come on. After it cooled down and after pulling the ECM fuse and replacing it the check engine light would come back on and it would start and run like normal. Now it's cooler and it does it frequently even on a very short drive. Now that it's cooler I can pull the ECM fuse, replace it and it starts right up. Any thoughts. Thanks so much.
You need to check the battery and ignition feeds to the ECM. For some reason the wires tend to corrode in the harness near the ECM. Sounds like you have one that is starting to fail. Temperatures affect resistance as well. The next time it won't start and the MIL is not on try moving the harness at the ECM with the key on and take note if it wakes up. May need someone to watch for the MIL. Good luck.
@@PhillipBailey I've been having some problems with some of my fuses not making good contact in the fuse box. Had issues with my heat/ac blend doors and had to bend the tabs on the fuses to make it work properly. Considering getting a new box that the fuses go in. Could the 15 amp fuse to the ECM be loosing connection and doing that. Had it happen the other night coming home. Hit a bump in the road and it shut the truck down. Pulled the fuse, waited, put it back in and it ran again.
I have never worked on these thing, but I am now with a dirtmax-bus-daddy and I must educate up. I posted earlier and basically guessed the issue... and see that the scanner I am about to get flags codes that are current, history, etc... so that would have told him the codes did not clear. I think he cleared them while the ground was bad... oops! Where do I get this fresh knowledge with no experience!? ...watching 100s of videos. Mine is a 2010 chassis 2011 engine 6.6L dirtmax LGH Turbo diesel High pressure rail. It cranked, died a couple of times in traffic, took me home 200 miles and died again parked at home on stilts... LOL
That is an awesome video. I just purchased a 05 lly and was having the com with ecu. I found blown fuse to pcm replaced it and got signal and it will start but after sitting a few it won't start. If I try to turn engine e over it will spin but not start. If I leave the key on after trying to start and unplug that pcm fuse and plug it back in the truck will start. Sounds like a bad wire? I dont know where your located or i would take the truck to you.
Well if it matters I'm in northern Ontario Canada near Thunder Bay. Its hard to say whats going on with your truck. Is it setting any codes? Do you have a scanner to view data while it's cranking? Will it fire up using penetrating fluid? Don't use either. Need to see if there's correct fuel pressure, rpm signals with the scanner. Good luck
Well ok. I started checking fuses because I had a no start or crank issue. I found the 20amp PCM B blown. I put a new one in and now that check light is on and the pats light is on too. It will crank now but will not start until I remove the 20 amo PCM B fuse and reinstall it then it will start up . It will be fine if I shut it off and turn it back on. If I wait more than 30 seconds it like rests and the pats light is on and it will not start until I cycle the fuse again. I dont have access to electrical schematics. Should I follow those wires to that fuse?
@@susanaruiz4104 the P1631 is a problem with the antitheft system but the U codes could be the cause as they are network codes. The security system which is in the BCM communicates with the ECM over the serial data network. Any module on the network could be taking down communications. Common on those models was the ABS module and the airbag module. You need to lab scope the serial data signal wire which if i remember is pin 2 at the DLC. It should be a 7 volt square wave signal. You could try unplugging the ABS module under the truck, tge air bag module which I believe is under the driver seat. Does it have an aftermarket radio? The radio is also on the network and an aftermarket radio often has a module to connect to the serial data wire so the chime works. This can be a problem as can an aftermarket car starter. Good luck.
Great video. I have an 05’ LLY also. I’m going to check that ground tomorrow. Mechanic said scanner is throwing codes in reference to the communication issue. I was driving fine yesterday and out of nowhere lost power. It will crank, but won’t fire. It also blew the fuse and everytime we put a new one in with the key turned it would blow them as well. I’m hoping it’s a simple ground issue and not a FICM or ECM issue. Any ideas? Thanks in advance.
A bad ground won't cause the fuse to blow. Which fuse blows? Look at a power distribution circuit to see what that fuse feeds. Probably have a shorted wire.
@@PhillipBailey I gotcha. Waiting on the tow truck right now to tow it from the shop to my house. I’ll go through it there. So, there’s no chance that it would’ve fried my FICM by blowing fuses?
@@michaelnoneya4833 the 40amp Stud #1 fuse should only be supplying power to the auxiliary stud typically to a trailer or camper power feed. Should no affect the engine. Do you have a trailer connected? Is this an 05 dirtymax? Does the mil come on and stay on with the key in run?
Does the MIL come on and stay on with the key on? Can you communicate with the ECM with a scan tool? Codes? Check all fuses for power to the ECM. Let me know.
As I am beginning to watch this... I am thinking the DURAMAX crappy harness setup strikes again. I bet you, a chaffed harness/wire, a bad connection in one of the pins, a crappy ground wire. worst a cremated ECM or PCB board sandwiched below the distribution box.
@PhillipBailey 2005 lly, cleaned all grounds power probed fpr plug had no power no interior lights dash nothing. Replaced the fuse box, no have power everywhere but now no crank. But it cranked before the fuse box replacement.
@Cavranger04 what fuse box did you put in? New by vin or used plug and pray? Does the mil turn on with key and stay on? Does the ecm talk to a scanner? Codes?
Your electrical skills are on point Mr.wizard. great job.
Good stuff, Phil! It's an education in auto technology watching you track faults down!
Thanks thats very much appreciated!
30 minute video saved me countless hours of diagnosis, hats off to you! What a great video and damn good mechanic, very few take the time you do, most would have wasted the $$ on a ecu and still be in the same boat!
Appreciate the feedback and the support. Glad it helped you out.
excellent explanation I congratulate you
he is a good teacher
Unbelievable skill and patience, I hope your customers appreciate you. Can't imagine a chevy garage solving this problem. Next time Space X has a wiring problem can they call you ?
You can let Elon know I'm always available for consultation...
H,iHaving the same thing with my 06 lbz classic..... going to check that bolt even tho im also not sure the ecm on mine is grounded there and my ecm is different than the lly. god i hope thats it..... You are the man. best and only vid of this clear and easy to follow step by step explanation.....n.. lots of others have had this problem and even with scsnners just started throwing parts t it... Im a good mechanic and have been wrenching since 1975 at 5 yrs old with my dad im 51 now,and this truck has been kicking my ass on this one... I have read and watched video after video on all other possibilties and all were other common issues fr these probs and nothing... The local port oregon dealers NO HELP AT ALL.......JUST BRING HER IN..... BS.......Thank you so much for posting this..... great stuff sir....... Thank you from portland oregon...
Does your check engine light come on when you turn the key to run? I've had corroded computer feed wires.
@@PhillipBailey Yes it do as i also had other and previous codes.... I can aslo clear them and if i jump the starter relay pins with a paper clip it will start and run and i can put the realy back in place but wont crank when i shut off and try to tr crank or restart.... im so confused.. my ecm seems to be working to some degree?? also still get p700 and u1001 ugh!!!!
@@sandimastodd P0700 is a generic code for the transmission controller requesting the ECM to illuminate the MIL. The U code could be your issue as that a communication error between modules. The TCM talks to the ECM of a high speed 2 wire can bus. Since the TCM tells the ECM if its in park or neutral if uts not able to communicate that the ECM won't energize the starter relay. Since you were able to get it running by bypassing the starter relay then you are correct in assuming the ECM is likely fine. Can you scan the TCM for codes. Have you tried driving it once its running does it shift normal. Check powers and grounds to the TCM. Hope this helps good luck
@@PhillipBailey I appreciate all the help.... Can you tell me the wire colors and pin locations and or numbers on the tec connector???? Let me know thank you. Im not real good with electrical scems....... Thanks again Todd.
@@sandimastodd All terminals at the TCM: Pin 63 pink wire from IGN 0 fuse in IP fuse box with ignition on, Pins 10 and 70 Orange wires from TCMB fuse in engine compartment fuse box hot all times, Pin 43 Purple Hot in crank position, Pins 9 and 59 Black/White both grounds at G102. Can you read codes and data from the TCM? Need a decent scan tool to access not just and OBD2 code scanner. Usually with a power or ground problem to the TCM there will be no communication with it. good luck
I’m having the same problem with my 04 gmc 2500 hd. I hope it’s the grounding issue you found…!
I’ll let you know what I find
You did a great job. I am gonna check my 2004 Chevy 4500 ground wires. It was running fine and I shut it off at a friend's place. Went to move it and it would not crank. I got the code u0105 which is fuel injector module problem. I think it said no communication or something similar. I almost bet it is a ground wire. I ordered a new module and that didn't help so I am almost certain that the ground is the issue or the power wire is cut or frayed somewhere. Tume to go look and thanks for.the great video! It will hell me to not forget the ground wires
Good luck hunting...
Heck yeah!! Very much appreciate your video!!! This was my problem!!
Glad it helped you.
I have a question
I have 6.6 duramax van 2006 g3500 and my van will start in the morning but after an half hour of driving all my dash lights go hay wire and then back to normal sometimes stay off .. after I stop I have have to wait at least half hour before it will start also sometimes I turn it off my key domes out but van stays running…… help
I have a 05 lly I have 30 tcm codes all electrical and the truck will go into reverse and drive but stuck in first gear will move about a foot then goes to neutral I've been tracing wires so far no luck I have power and ground to tcm and replaced tcm and ignition switch and changed fluid and filters which looked good any ideas?
Great help, thanks so much 😊 10:28 pm Jan 18/24
Electrical genius
Hey man, I got a 2003 lb7, my problem is when I start the truck it starts completely fine, but when I go to turn it off nothing happens. Truck still runs.. I have changed ingnition switch. When I changed the edu relay it went completely back to normal, after 30 minutes of driving the relay got hot and all the problems came back.
Poor connections at the relay may be causing it to heat up. I believe its supposed to be a high power relay. I'd recommend oe HI PWR
@@PhillipBailey not sure what you mean by that, I’m not a mechanic
Mine is the sending unit for as I know fuel pump was replaced only worked to get us home mine turns over but will not start.
i got a 2007 GMC Sierra 6.6 diesel .. same problem .. no start and no communication .
someone swapped out the engine and now it won't start ..
tomorrow I'm going to check all the grounds ...
There are a couple grounds near the right motor mount. Good luck.
@@PhillipBailey yes.. thank you. i will give you an update of what the problem was and what fix it ....
Pretty awesome Mr. Phillip Bailey. I have a 2011 LML Duramax. Back when it was a lot hotter, when my truck got very hot it would shut off and like on this video it wouldn't crank and the check engine light wouldn't come on. After it cooled down and after pulling the ECM fuse and replacing it the check engine light would come back on and it would start and run like normal. Now it's cooler and it does it frequently even on a very short drive. Now that it's cooler I can pull the ECM fuse, replace it and it starts right up. Any thoughts. Thanks so much.
You need to check the battery and ignition feeds to the ECM. For some reason the wires tend to corrode in the harness near the ECM. Sounds like you have one that is starting to fail. Temperatures affect resistance as well. The next time it won't start and the MIL is not on try moving the harness at the ECM with the key on and take note if it wakes up. May need someone to watch for the MIL. Good luck.
Check out this video this may be related to your problem. The electrical is pretty much the same I believe. th-cam.com/video/5VbNGZc70v0/w-d-xo.html
@@PhillipBailey Thank you so much.
@@PhillipBailey I've been having some problems with some of my fuses not making good contact in the fuse box. Had issues with my heat/ac blend doors and had to bend the tabs on the fuses to make it work properly. Considering getting a new box that the fuses go in. Could the 15 amp fuse to the ECM be loosing connection and doing that. Had it happen the other night coming home. Hit a bump in the road and it shut the truck down. Pulled the fuse, waited, put it back in and it ran again.
@@eddieclark7025 the fuse boxes are a common failure due to salt if they used that where you live.
I have never worked on these thing, but I am now with a dirtmax-bus-daddy and I must educate up.
I posted earlier and basically guessed the issue... and see that the scanner I am about to get flags codes that are current, history, etc... so that would have told him the codes did not clear. I think he cleared them while the ground was bad... oops! Where do I get this fresh knowledge with no experience!? ...watching 100s of videos.
Mine is a 2010 chassis 2011 engine 6.6L dirtmax LGH Turbo diesel High pressure rail.
It cranked, died a couple of times in traffic, took me home 200 miles and died again parked at home on stilts... LOL
That is an awesome video. I just purchased a 05 lly and was having the com with ecu. I found blown fuse to pcm replaced it and got signal and it will start but after sitting a few it won't start. If I try to turn engine e over it will spin but not start. If I leave the key on after trying to start and unplug that pcm fuse and plug it back in the truck will start. Sounds like a bad wire? I dont know where your located or i would take the truck to you.
Well if it matters I'm in northern Ontario Canada near Thunder Bay. Its hard to say whats going on with your truck. Is it setting any codes? Do you have a scanner to view data while it's cranking? Will it fire up using penetrating fluid? Don't use either.
Need to see if there's correct fuel pressure, rpm signals with the scanner. Good luck
Well ok. I started checking fuses because I had a no start or crank issue. I found the 20amp PCM B blown. I put a new one in and now that check light is on and the pats light is on too. It will crank now but will not start until I remove the 20 amo PCM B fuse and reinstall it then it will start up . It will be fine if I shut it off and turn it back on. If I wait more than 30 seconds it like rests and the pats light is on and it will not start until I cycle the fuse again. I dont have access to electrical schematics. Should I follow those wires to that fuse?
I got a list of codes. I would attach a pic but I don't know if I can.
I got a P1631, U1000, U1301,U1041, U1096 and some air bag loss of communication.
@@susanaruiz4104 the P1631 is a problem with the antitheft system but the U codes could be the cause as they are network codes. The security system which is in the BCM communicates with the ECM over the serial data network. Any module on the network could be taking down communications. Common on those models was the ABS module and the airbag module. You need to lab scope the serial data signal wire which if i remember is pin 2 at the DLC. It should be a 7 volt square wave signal. You could try unplugging the ABS module under the truck, tge air bag module which I believe is under the driver seat. Does it have an aftermarket radio? The radio is also on the network and an aftermarket radio often has a module to connect to the serial data wire so the chime works. This can be a problem as can an aftermarket car starter. Good luck.
Great video. I have an 05’ LLY also. I’m going to check that ground tomorrow. Mechanic said scanner is throwing codes in reference to the communication issue. I was driving fine yesterday and out of nowhere lost power. It will crank, but won’t fire. It also blew the fuse and everytime we put a new one in with the key turned it would blow them as well. I’m hoping it’s a simple ground issue and not a FICM or ECM issue. Any ideas? Thanks in advance.
A bad ground won't cause the fuse to blow. Which fuse blows? Look at a power distribution circuit to see what that fuse feeds. Probably have a shorted wire.
@@PhillipBailey I gotcha. Waiting on the tow truck right now to tow it from the shop to my house. I’ll go through it there. So, there’s no chance that it would’ve fried my FICM by blowing fuses?
@@michaelnoneya4833 I doubt it but anything is possible. Which fuse is it that blows? I'll have a look at a schematic
@@PhillipBailey The Stud#1* fuse
@@michaelnoneya4833 the 40amp Stud #1 fuse should only be supplying power to the auxiliary stud typically to a trailer or camper power feed. Should no affect the engine. Do you have a trailer connected? Is this an 05 dirtymax? Does the mil come on and stay on with the key in run?
I need you to check out my 03 dirty max lol no glow plug no crank no start lol
Does the MIL come on and stay on with the key on? Can you communicate with the ECM with a scan tool? Codes? Check all fuses for power to the ECM. Let me know.
As I am beginning to watch this... I am thinking the DURAMAX crappy harness setup strikes again.
I bet you, a chaffed harness/wire, a bad connection in one of the pins, a crappy ground wire.
worst a cremated ECM or PCB board sandwiched below the distribution box.
I need you in my area ive messing with mine for month's 😂
What year is yours, what's going on and what have you done
@PhillipBailey 2005 lly, cleaned all grounds power probed fpr plug had no power no interior lights dash nothing. Replaced the fuse box, no have power everywhere but now no crank. But it cranked before the fuse box replacement.
@Cavranger04 what fuse box did you put in? New by vin or used plug and pray? Does the mil turn on with key and stay on? Does the ecm talk to a scanner? Codes?
I’m having the same problem with my 04 gmc 2500 hd. I hope it’s the grounding issue you found…!
I’ll let you know what I find