GM Truck Stall, No-crank, no-start Case Study -Part2
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- เผยแพร่เมื่อ 21 ส.ค. 2024
- Who's ready for Part 2?!?
Where were we?....ah yes, let's check the PCM powers and grounds!
Naturally, this crazy Trailblazer has another surprise in store for us...
Part 1: • GM Truck Stall, No-cra...
Enjoy!
Ivan
![ออกพรรษาน้ำตาหล่น - แอน อรดี [OFFICIAL MV]](http://i.ytimg.com/vi/PFZtOcY9ONA/mqdefault.jpg)
4 years later and this video is very relevant, thanks
There is no expiration date 😄
Don't feel too bad. I drove 6 hours to diagnose a car that a shop was about $4k deep in part cannon ammunition for a no com on the ABS module. I asked them to verify ALL powers and grounds were good and they said yes. I drove out there and found the brake switch fuse blown due to a failed brake lamp switch. It was also the turn on signal to the ABS. I can't stress enough verification of powers and grounds and making sure they can carry a load. Don't get me started on pin tension issues.
Nicholas Bibeault it’s sad how many techs don’t even know the basics. And most of the time the customer pays the price..
Can you imagine spending $1,000 on a module only to find out a $25 brake light switch was the problem? Some shops have no code, no morals and no respect for their industry or a customers fair trade.
Well done Ivan! Great news for the owner. No ignition driver damage👍😁
Take it from an electronics engineer: If electronics are behaving oddly, check the supply voltages first.
Sage advice :)
My nephew asks "What are you watching?" My reply: "the diagnostic Jedi".
Biggest enemy of diagnostics is complacency. Glad to see you finally followed your own advice and went back to basics. Well done, technician!
I love the fact that you still post the video, most of these guys wound not have the B to do the same and there was still a lot to lean from your video. thanks for keep it real man.
That's my goal...to keep it real. Successes and mistakes included!
😂 oh -four letter word! Oh man! Now all the armchair diagnosticians are going to cry "you should've checked fuses first!!" they probably wouldn't bother with the current waveform. Job well done bud! Kudos Ivan 😃 for not skipping anything.
Super Mario Diagnostics
Hey that's right, most people do the easy thing first like swapping things or replacing fuses that's not even blown. I love both my test lights (first love tools) then I love my off brand power probe.
And most of those guys are the type that would "fix" it by keeping a spare box of fuses in the glove compartment.
Kelly R Johnson or better yet, hand the customer a box o' fuses🤣
Lol, a friend from church car stall because of alternator problem. I made sure I did my powers and grounds on the alternator. Once fixing the alternator the AC compressor kept blowing the fuse. So I figure the AC compressor was drawing too much amperage and killed the alternator. So after replacing alternator the car was charging.
Long story short he called me up at O'Reilly's ask me what fuses his car need for the AC compressor like it will blow after 5 minutes but he was okay with keep on replacing it....
Johny Harbinger he didn't post this video in the hopes of getting advice LOL
My trailblazer did the very same thing I started it was writing down my milage it died and no crank I found your vidio I did all the tests till you went to part 2 for some reason it wouldn't come up so I checked a few others and according to the it was the switch so I bought a new one didn't work do I tryed again this time part 2 showed up I couldn't belive it when you said a 15 amp fuse I looked down and could see it blew and yes it was missing had to replace the coil thanks a ton for your help saved me a ton of time and money keep up the good work
YES! "More than 1 Hour Diagnostic"YOU deserve it.
Yup, I got an escape from a guy for $500. Crank no start, all he did was throw parts at it, he kept running the battery dead so no codes. After bringing it home it sounded suspicious that the compression sounded like it increased over time. It would crank like a dead battery but the battery voltage remained normal. On a hunch I unhooked the EGR tube and it fired. The pcv valve had gone bad and wasn't restricting enough causing a vacuum leak making the engine run pig rich, in turn caused the cat to "melt-down" and plug up. It's amazing how much using your tools helps, it's also amazing that a $5 piece of plastic can destroy a catalytic converter.
Oh dang. Another fuse but the coil was a good find and the owner seems happy it wasn't a computer. Nice diag Ivan.
With my luck the spark plug would be bad as well haha
I really like your videos as you really have a proper structured approach to narrowing down and isolating the faults. The detective work you put into finding out the cause makes you the Sherlock Holmes of automotive diagnostics. I also commend you on your effort and hard work to video record every step of the way to finding out the root cause. It can be cumbersome and time consuming to record. Most mechanics will just want to dive in straight to find and fix the fault instead of taking precious time to record and provide a detailed commentary. Keep up the very good work!
That is a really positive and motivating comment. I appreciate it, Hanif!
Glad to see that you made it to a conclusion. On a no start issue I always start by checking all the fuses first just to save some diag time. You can retrace the circuit later if need be.
This is why I love this channel.... Take your diagnostics to the end, prove your thesis, before you fail parts swapping 101.. Good job, Ivan!
Scientific method may take a bit longer, but never fails in the end :)
Ivan, I was leaning on calling the ECM too, EXCEPT, what would cause THAT to fail? You nailed it, and the ECM lives another day!
Remember the rule. Always related to pink wire😂
Dammit Keith it IS always that pink wire xD
The GMP rule ...
It was cool to watch you work your way through the 2 videos and get to resolve the issues.
Great diagnosis Ivan. Agree the coil probably caused the fuse to blow. Acted like a ground but that is why we always check powers & grounds before condemning a module with multiple powers & grounds b/c the power input in one part of the module may affect an output to another part of the module. Cranking by jumping relay load side with key "On" checking spark would have found it also which is the path I usually go but just goes to show there are sometimes multiple paths you can take to come out with the same diagnosis in the end. The ground for the PCM was actually G108 not G106 had me thinking Mitchell or BBB was wrong but after I enlarged BBB diagram to 200% it was G108 not that that mattered with the diagnosis unless you had to search for it if it was bad. It's always fun to see the different paths people take and with your videos there is usually a twist. I've just had a 2014 Traverse in the shop that wouldn't crank and the PCM wasn't supplying the ground to the starter relay control circuit and the ECM was fried. I should have made a video on it. Keith said they are running into that in the body shops when they have low battery voltage. Then the ECM I received from the dealer in a taped up box was previously programmed with another VIN and ECM programmed but immobilizer wouldn't however I brought it up to the Parts Mgr attention before I left and sent him the photo of the other VIN on the laptop before attempting to program it so after it failed to program he just ordered another PCM and next day I programmed and running in @20 minutes. I get my next part at cost so my truck is going to get a serious upgrade soon :D
Is it just me, or do the newer GM vehicles like to eat PCMs?
It's the new architecture and they make it so you can't swap them & reprogram to another VIN. It's still impressive the interval between mean time failures.
I have 4 vehicles starting with a 1998 Ford Explorer that I try to do all the maintenance and repair on. I recently started watching your videos on a regular basis. They are extremely helpful. They are detailed and clearly explain your thought process as you work. They have been very helpful in getting better use out of my picoscope which I used recently to call a bad crankshaft position sensor on a 2007 Jeep GC 5.7L. Thanks for the education.
That's awesome to hear, Scott! The Pico is a very powerful tool :)
Hey thanks a lot for your video!! It really helped me out on my 2003 Chevrolet Avalanche!
My Avalanche died while driving: suddenly it just stopped running, giving me a brake-system-message (which, I discovered later, popped up because of the CPU shutting down). After that, it wouldn't do anything anymore: not even cranking. It would only react to turning the ignition key by turning on the dashboard gauges and lights.
After a lot of searching, I discovered it was my fuel pump that had died, causing its fuse to blow. And that same fuse happened to be supplying the CPU as well... Causing the truck to react to nothing, not giving error messages, ...
Thanks to your video, I learned that the GND to the starter relay is controlled by the CPU. This is NOT mentioned in my Haynes repair manual!!!
I measured the GND on the starter relay, and it was OK. But after seeing this video, I measured again, and found out that the GND disappeared when turning the ignition key!!
Thanks a lot, keep up the good diagnostics over there!!! Greetings from Belgium :-)
Nearly the parts cannon got fired,you could hear the frustration in your voice,but you went back to providing the the ecm was bad ,found the real fault cause,and made a brilliant diagnosis we should learn from,always always prove all the powers and grounds are solid,bloody good video,enjoyed both parts,and have lived your frustrations,thanks again,keep up the good works,live and learn .
Thanks for the motivational comment, Sarah!
It's ironic you uploaded a video where the power feeds end up being a problem. I just had a volvo truck kick my butt because I missed one of the power feeds and when I fixed the issue it worked fine. Great diag as always Ivan, Thanks for the awesome content. P.S. I waited till the end of the video before commenting this time!
These mini series make the day go by much more smoothly! Thank you!
I saw no steps that you took that were wrong. You kept at it and worked your way to the problem systematically. Excellent Ivan!
There are many ways to skin a cat :)
I watched a staten island video on a ram with a coil that surged the pcm and shut it down, and remembered this video. The coil that reeks havoc !! Good find in both videos!
Nice I like they way you don’t just give up and say computer you tested all the powers and grounds man now days the misfire counter saves a lot of time I remember pulling plug wires getting shocked to see if it made a difference then try and find out plug, wire or distributor then compression test hours of work that now the touch of a screen your were lucky if you knew someone with the big sun machine or had a distributor tester if you set the valves to tight the engine would hydro lock and twist the distributor it start dead on and be off 7 degrees on the last cylinder how things have changed nice video look forward to the next one
randy hughes I miss my distributor tester!
What’s a distributor? ;)
definitely a surprising end result mine did have a blown pcm fuse but still no crank,leaning towards air bag module.ill check it next if no good end result i maybe inviting everyone to a big wienee roast and chevy will be the fuel for the fire,thanks again for awesome videos
Glad you checked powers and grounds at the PCM. Scanner Danner always preaches that before you call a computer, you have to check powers and grounds. Guess it proved true here too. Great case study.
Detailed low tech examination of powers and grounds, simple but effective. Lot of problems with this baby and certainly difficult to diagnose. Job well done.
Awesome and thorough diagnosis brother .
Let's get to the bottom of this! Much anticipated 👍
Dr Ivan to the rescue again..good job Ivan.
great 2 part series Ivan
Nice diag only reason why I said half of pcm meant partial pcm is dead with no fault codes when the pcm does it self check it can't put out checking voltage if it ain't alive hence no codes had it on Euro cars depends on what part of I C has gone down. Powers and ground checks can't beat it
I love how when Dude is telling Ivan everything he's done, Ivan just kind of dismisses and and starts talking. The man does not want to be interrupted
Only Ivan could make a blown fuse so exciting! Thankfully you kept your shirt on this time Ivan!
haha the heat wave was over by that point ;)
I had the same problem with a H2 Hummer (PCM fuse blown) I had no sparks nor inyector pulses but I had the starter working fine. Guess what? The fuse blown because somebody installed some aftermarket lights using the PCM fuse wire to feed the circuit! About the weird behavior with the vent solenoid I think is trying to open but there is too little amps going to the control side of the solenoid, is just the same scenario when a relay is clicking on/off due to low voltage.
Thanks. you solved my issue that i was unable to diagnose in my trailblazer. WOW! u r good.
Great job again Ivan....I think it would have taken me a lot longer to find this fault & why that fuse blew. Keep up with the great videos. Cheers Andy
Thanks for the support Andy!
Good stuff. Thanks Ivan
I was about to say, wow Ivan, you are too quick to say the PCM is bad! I am glad you went with the imaginary naysayers! Great diagnosis!
Those trailblazers are hell on those coils, Replace MANY MANY of them :)
Damm it... Wrong again. I was putting my money on the green crusties!!!!
Great case study Ivan!!
I'm sure the green crusties are waiting to strike on this one lol
Lol was a good one this.
different approach may of found that sooner, if owner had mentioned coil replacement think I may of hit that area quicker .
bad new ign switch made it messy .
Some guys always like checking fuses and to fair it not a bad idea at times look at fuses when nothing else working out.
If you called a computer on that you would of been in remorse for months lol .
Cool lesson on keep testing and assume nothing :-)
a coil and a fuse and job jobbed , didn't guess that lol ...
One would have thought the driver would have felt the misfire...Strange a P0302 wan't stored...Nicely displayed procedure Ivan.
yeah not sure on the strategy there lol
well well there's ya dinner..good final outcome for the owner Ivan, helps to keep digging well done..
Nice video Ivan you always said from the beginning there was a problem with the ECM.
Gut feeling!
Damn naysayers LOL!... Nice two part vid Ivan!
My man using the great Milwaukee tools
You and Eric o- what a team !!!
Eric was with me in spirit working on the "ole Chevrolaaaay" ;)
I’m a simple man.. I see Ivan post a video and I click play...
~grabs some munchies and enjoys the adventure~
haha it's nice to sit back and let someone else do the work sometimes ;)
true that. the one problem you guys create for me though, you motivate me to fix stuff but sadly my car is too damn reliable and nothing to fix. guess i could take the AvE approach "if it ain't broke, fix er till she is"
Yeo I learned so much from this video Thanks for being very detailed my brother
Reminds me of that Dodge truck you worked on for Keith. Nice diag Ivan, that was a good one. Thanks!
Anytime!
Well I was wrong it wasn't a bad ground but a bad power. Great video ivan I think when the coil went bad it pulled a high amperage and blew the fuse maybe?
Hi Mike, yeah that's my theory too...shorted primary winding took out the fuse with it!
I was sure it was ground. Glad to see you saved him. Nice work!
It's Alive!!!! Awesome Ivan. I was guessing bad fuel pump took out something, but guessing and working are not the same.
I bet you are so glad you did those final checks for powers and grounds towards the end there before calling the computer. Sometimes we can do the 99.9%, then call it based on "knowing" the last 0.1% has to be just fine by gut feel and past experience. What more experience tells you is to go the extra inch to go to 100% even if you are sure you "know".... they say something about assumption, all I know is it certainly has a way of kicking you in the nuts at every opportunity no matter how tiny the assumption.
Good job going the extra inch at the end of an extended diagnosis and under time pressure - those conditions are the worst for somehow exacerbating the tendency to call it at 99.9% confidence and internally believing it "proved". Some kind of nasty cognitive blind spot occurs. Been there, done that... still catch myself doing it at times.
Absolutely. Great comment!
Ivan,
Another great video, case study, and diagnosis. Thank you!
God bless
Paul
Glad you enjoyed it, Paul!
Great job Ivan
Good job..IVAN
A big thumbs up man.... Cheers!!
Sweet! No PCM needed.
Plot thickens on mine,lol.unhooked all modules checked starter relay all 4 pins show ground called owner of truck asked if any previous work done to truck of course a hack mechanic put a motor in the truck to make a long story short wiring harness pinched between motor and trans,I guess should of done a better visual inspection,thanks for all you do on helping us on trouble shooting it really means alot
Great find! Thanks for the comment :)
Awesome! You always give your customers little extra!
Great determination, you followed the evidence and resisted the life of the parts cannon.
great video ivan i not saying nothing about running through the fuses first but it runs and nail the misfire
Another happy customer. Thanks for sharing a great video. 👍
He was ecstatic!! Hopefully I converted him from being a parts cannon junkie lol
Good thing you went all the way to check power and grounds on the ecm and found that open fuse.
Thanks for the video Ivan, it pays off to be thorough . A lesser a technician might have called the PCM and just went with it.
It's a good thing that you were thorough or you might have been bitten. Nice job, Ivan.
Gotta trust the data, no matter how unlikely the problem may seem!
Fantastic chase down. That was a tough one.
Great diagnostic Ivan.
Almost called a PCM for a fuse, sometimes you gotta love the haters, love the vid as always.
I always run a test light down every fuse possible before I dig deep. Yes i know it can throw the diagnosis off.. in this case it would have helped you in the right direction
Thanks for sticking with it!! Could see and hear the frustration about testing all the power (+) going in to the PCM 😩😩😩 BUT as I said be for,,, I just do it Know matter what.. Great Job Bro’ 👍🏻👍🏻👍🏻👍🏻👍🏻 thanks for the video
That was a real eye-opener for me. Never seen a computer be "happy" with a missing power like that lol
Pine Hollow Auto Diagnostics ,, ya that will spin you around a little bit with 3 or 4 (+) inputs and they start testing good it’s very easy to just stop and call it a bad ECM’!! 😩😩😩😩😩.. I’ll get one like this every few years most of the time “Someone” has been doing stuff ???? And you NEVER get the truth.. The good old,, It was running great then it just stopped running and won’t start or crank. Hmmmmmm 🤫🤫🤭🤭🤭🤭
Hey, Ivan, My Trailblazer died did some checks I found that the park/safety switch was bad but was not the cause of the crank no start took voltage measurements at the ignition switch and found battery voltage (11.8) coming in and 10.6 volts coming out I changed the switch and started right up. something for your viewers to think about if they have similar issues. and great video goes to show to test not guess
wow that's weird...usually 10.2V is still enough for most things :)
apparently, the switch was grounding the start circuit I checked the new switch and it was battery voltage in and battery voltage out what was odd all the fuses were good
Wow I never saw that coming lol great job Ivan!!!
I didn't either hahaha
Great job Ivan , like you said - so very difficult to Call computer and you proved it !! Thanks.
Damn good diagnosis Ivan I salute u brother awesome work u saved this guy a lot of heart ache and pain Bless you man and thanks for Sharing
Great part 2 Ivan nice find thought for sure you would find a bad ground and yes you are right you have to check your powers and grounds before calling anything. Saving this video for reference just in case. Great video until next time PEACE.
Wow what tail chaser👅 nice follow through to the finish, way to percivere
How bout that eh. Ivan you know I was watching so ya just had to check power and grounds. LOL Nice one buddy.
Part 2- I thought your Silverado buddy was going to show up demanding that Ivan check his alternator for him. Lol
Hi Steve! How are things in Canada? Thanks for dropping by the channel, just like the "good ole days" ;)
Nice video Ivan.
Excellent job. I really enjoyed both parts Ivan.
Thanks for the comment Richard, much appreciated :)
Great video as per usual. Too bad you're not closer to my area. I'm experiencing a Chevy 1500 Silverado intermittent no start/ no crank issue. I've been watching youtube vids like crazy the last few weeks. I know so much more than I did before lol. The thing I know for sure is I need to get myself a cool multi-meter like yours lol. Thanks for posting your videos!
Excellent diagnosis Ivan 👍 Thx for the video.
My pleasure!
Nailed it once again, thumbs up!!!
Well done, Ivan.
Way to go. Good one Ivan.
Great 2 part series Ivan.
Good one! Well done Ivan!
that was a good story
. and I learned quite a bit.
mission accomplished
That would've been a painful lesson for someone blindly firing the parts cannon at that one!
This was a great one, Ivan! Looking forward to the next one. :)
good find... must check ALL fuses
Nah I just check the one that's BLOWN ;)
Nice job Ivan.
Awesome work Ivan!
Great thinking! Love it
Thank you Ivan. Good job. I appreciate your videos.
Great job Ivan.
Parts Canon 0? Lol! The fuse was lit buddy! If it weren't for you wanting to shush the naysayers it would've been BOMBS AWAY BABY! Lol... But it's good to know you are a mortal..mostly.