SOLVED! All modules failing randomly or different starting point?

Mooseman

Moderator
Dec 4, 2011
23,693
Ottawa, ON
More than likely, someone put a fuse in there thinking it was missing (or a sunroof would magically appear :laugh: ). It's also possible that the power side of that fuse is there but not the circuit to the sunroof. This would not be a problem if a fuse was put in there as the power would go to nothing.

I wouldn't worry about it either way.
 

TJBaker57

Guru
Aug 16, 2015
2,241
Colorado
interesting from the wiring diagrams is that there is a direct battery line as far as I could tell and in my mind that just feels wrong that there's a hot at all times connection.


I don't know which thread it was in but somewhere I explained that practically every computer module in the vehicle has a hot all the time connection. The vehicle computer network may "go to sleep" but all of those modules are still powered and listening for the BCM or Drivers door module or Liftgate module to sound Reveiile.
 

Elizabetty

Registered Member
Original poster
Dec 2, 2022
132
Wisconsin
I don't know which thread it was in but somewhere I explained that practically every computer module in the vehicle has a hot all the time connection. The vehicle computer network may "go to sleep" but all of those modules are still powered and listening for the BCM or Drivers door module or Liftgate module to sound Reveiile.
I was able to go back and find it. Sorry about that. It completely spaced my mind and I must not have wrote it in my notes.

Mod edit: Please add your response to a quoted post outside the quote. Otherwise we don't really see your response.
 
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fixit

Registered Member
Apr 27, 2021
15
Austin, TX
I have a question for you. Do you know the history of the vehicle, before you bought it? Has it ever "lived" in a flood area? The things that you are describing sound like classic submergence damage. Sometimes, you can detect it by inspecting connectors, but you will need, ideally, an inspection microscope. If you don't have one of those sitting on you work bench, you might manage it with a descent jeweler's loop. Find a bladed type of connector that has brass blades. pull the connector halves apart carefully and inspect the contacts for tiny, (dust speck size), green spots. That's copper oxide. They are not conductive enough to cleanly convey some signals from one half of the connector to the other. You may have to inspect a number of connectors to find obvious evidence of corrosion. I'm sorry to say that the only real fix for it is a new wiring harness. I hope that is not what you are looking at, but if it is, then the smart money is to find a buyer for it. Thousands of cars are flooded every year. I have seen entire new car dealerships with hundreds of cars with muddy water half way up the windows and their lights flashing on and off and windshield wipers sloshing around under water. Rumor has it that a lot of those were cleaned up, given new upholstery and shipped to other dealers around the country. You would probably never be able to prove that they had been flooded out. You can, though, usually find out where a car or truck was after the showroom. If it came from an area and time where there was flooding, then I would be very suspect. If you must fix it and can't afford a complete wiring harness and you have endless patients, go to Home Depot or a welder's supply and buy several brass or stainless steel bristle "tooth brushes". Now go to an auto parts store and buy several cans of CRC Battery Terminal Protector, (green spray cans of red greasy stuff). Start taking connectors apart and brush cleaning them ,then spray a them with a thick coat of terminal protectant reassemble them and hope for the best. I do hope that you find a single point fix for your problems, but it sure sounds like a typical flood damage problem. Good luck, Fixit
 
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Elizabetty

Registered Member
Original poster
Dec 2, 2022
132
Wisconsin
Grab your reading glasses, a cup of joe, and take a few minutes to kill some time.

I think this can be closed. My last issue is something that I don't think will land any resolution here. If anything, it may just end in frustration with me and I don't mean it to go that way.

Thank you for the diagrams and the helpful tools and PDF files. I've used everything I could get my hands on short of the infrared heat device as I didn't need to go that far once I figured out my burning smell at the fuse box actually being something non electrical. With your help, (everyone), I was able to change my ignition switch, replace multiple electrical connectors, repair some questionable wiring sections, remove inspect and clean a dirty fuse box, and handle really bad grounds ....Though I did break a bolt or 2 in the process lol. Additionally, I began learning how GM vehicle class 2 databus communication works..... Which brings me to my potential frustration and confusion.

Any electrical problem now is only when I plug in my bluetooth dongle to read codes. If I don't do that, I have no issues. I don't have a check engine light and was only using it to address codes that can tell you something could be going on even if it's not bad enough to throw a light as well as to learn how to read and understand live data that it was able to display. I'm not looking to start an argument here or open a can of worms because I have been told here repeatedly that the bluedriver USB obd 2 dongle and app does not write to the PCM but there is definitely something happening with the dongle as far as maybe it having a short itself causing everything to spaz out or it simply is not a well-made device for GM vehicles. --- When it is plugged in, I can hear electrical components clicking and crazy live data is reported. The live data is inconsistent and the stored codes and scanned codes are always inconsistent. Driveability will worsen the longer it's used. For example, I may be looking at fuel trim data and I will hear the doors randomly start clicking, not locking but like the module inside clicking, same with items in the dash. I will then see the coolant temperature update to say it is negative 22゚. Then it will suddenly jump to 269゚. When reviewing this with a mechanic and thinking it was the pcm, i was told the pcm is confused from data being scrambled, for lack of a better word, due to a bad dongle. Once unplugging it, I will still have a poorly performing engine. I won't have a smooth riding suspension or brakes that respond consistently. Modules will be doing things as if a ghost has taken over. I ran this "coincidental" test multiple times after being told its the dongle. The only thing that solves it after it being plugged in and doing a scan or reading live data is resetting the PCM, doing a bajillion drive cycles to have everything back to normal, and then I would do the experiment again and once the bluedriver has been used to do a scan or view live data, all electrical noise starts again and performance changes so drastically it's like I'm suddenly driving someone else's car. It does not resolve on its own when removed even after doing a few drive cycles and I will have to do a PCM reset, go through the whole adjustment period of drive cycles and eventually have a nice running vehicle again. I should mention this also includes making sure I am draining any stored static with the longer reset process with battery to truly drain charge from modules and not a simple remove fuses for a few minutes. That doesn't fix it.

After all this, I went to the bluedriver reviews where I bought mine and specifically looked at the negatives. What I found interesting was that a majority of the negative reviews were nearly identical to all of the stuff I've experienced, more than what's listed here, and nearly all of them were related to GM vehicles, especially in the years around when mine was made. I considered posting my screenshots of it here, but again, I don't think this is anything any of us are really going to agree on so I'm simply posting it here as my final comments before this is closed.

This leads me to believe that I could test this theory with a different device. The port was confirmed to not have any shorts. With his multimeter, he did to teach me how to use the suggested methods you gave me and showed me I don't seem to have any issues on any of the wiring itself that we spent the day on. It specifically seems to happen with the device which I can only assume is defective inside, but I'm not convinced. If this is true, that would mean it was defective immediately from purchase because I had similar issues with my Buick lesabre, my GMC sierra, and now this Chevy trailblazer. I chalked up the other two vehicles to being really bad luck with electrical issues. The part that makes me say no, it isn't the device being defective and it's the ability within this device to work with this particular setup, is the fact that I used it on a 2007 Saturn Vue during the same time using it on my Buick and Sierra and never experienced problems.

Yes I know there are better scanners and yes I know you have given suggestions here to point me in a better direction when it comes to learning live data. I know I have other options and a lot of learning to do, but without starting a war, I just wanted to post my particular personal findings through my own experiences that say whether a device is supposed to be able to have the ability to do something or not, this device certainly confuses my PCM or I live a highly coincidental life. I understand if it had a short, that would answer all the questions, but it certainly doesn't seem to have an issue on the Saturn.

Thanks for all of your help in guiding me through everything I was able to do myself. I will be investing in a good code reader. I have a lot of interest in learning live data and find it fascinating how three different pieces work together for one engine function so the bluedriver will be leaving my life for bigger and better things but this is my experience with it so far.
 

budwich

Guru
Jun 16, 2013
1,816
kanata
There is more to "electricity" than a simple meter can disclose. As a result, higher levels of troubleshooting are needed that include monitoring the bus both electrically (with a scope) and logically (with some form of snooper / protocol analyser) to determine what's up. It is unlikely to be resolved by you at the level that you are at but as you surmize, an alternative interface device will likely get you to a "better life".

Hopefully the "story board" will be a happy / less frustrating one in the end.
 

TJBaker57

Guru
Aug 16, 2015
2,241
Colorado
On December 3rd in this thread I recommended a device that now sells for about $13.

That and a FREE Android app (not affiliated with the device) can enable you to see things that no other device will regardless of cost.

The device itself does not come with software of any kind.

The Bluedriver and its software requires you to hand over the reins and become a passenger on their bus.

You have no say as to what it is going to do once plugged in.

My preference is to keep the reins in my own hands.

This approach requires one to learn at the least some basics to do things like read and reset codes (from ANY module, not just the engine). But it is a fairly simple matter and anyone can do this. And those that do will have a far better understanding of just what happens on that setial data bus.


Optionally one can choose to use one or more smartphone apps with the above mentioned device if one desires, especially useful for analyzing live data. There are a few very good apps out there for a few bucks each.
 

mrrsm

Lifetime VIP Donor
Oct 22, 2015
6,371
Tampa Bay Area
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https://gmtnation.com/forums/threads/how-to-use-pico-2204a-hantek-1008c-oscilloscopes.20423/
 
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TJBaker57

Guru
Aug 16, 2015
2,241
Colorado
Observations...

Video one states pin 5 goes to the ECM. Nope. Our pin 5 goes to chassis ground at G102.

This can be significant with our trucks, having two different chassis grounds run to the one DLC. I once diagnosed online an issue a fellow had where when he plugged in his OBD2 adapter the adapter and the DLC port both experienced a meltdown. Seems his G201 was a bad ground and all those components, including the blower I think, sought a ground path which they found when he plugged in the adapter which then completed a circuit from G201 through pin 5 to his adapter then back out on pin 4 and out to G102 by the underhood fuseblock on the inner fender. Wasn't pretty.

Screenshot_20230123-201153_Drive.jpg



It also mislabels OBD2 pins 6 and 14 which are for ISO 15765-4 Canbus communications.

OBD2-Connector-Pinout.png
 

Mooseman

Moderator
Dec 4, 2011
23,693
Ottawa, ON
I'm not looking to start an argument here or open a can of worms... but without starting a war,... I don't think this is anything any of us are really going to agree on...

All I can add here is that, at most, we can agree to disagree. Anything beyond that, we (the staff) bring it back into line. We have rules and we enforce them. Thankfully, violations are very very few and far between. We have a good bunch here. If you do happen to feel like something is out of line and we missed it, just hit the Report button.

We're all here to help each other out. :grouphug:
 

Elizabetty

Registered Member
Original poster
Dec 2, 2022
132
Wisconsin
Everyone's been wonderful. We can agree to disagree until I learn more and agree with everyone. HAHAHAHA. I was just trying to tiptoe into saying hey I"m gonna say something that will sound dumb to most but is all I have to work with right now. :wink:
 

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