I had something similar happen and it was an obvious short on the ECM, like black scorch marks on the pcb inside the protective jello. Wasted a bunch of time testing and resetting when I wished I just popped the cover and looked first, as it was obvious. Ended up replacing the module easily enough. Good luck, and I hope it’s not a CAN bus issue. Those can be painful. Friend had a nick in the harness that started to corrode and cause problems. Not fun.
Ugh, CAN-BUS... Talk about some unnecessary bullshit.* I'll check if there are any TSBs for that, but I doubt it will turn up much; I don't want to be "that guy," but on a problem like this, I'd really need to see it to be sure of anything. HOWEVER, I can give you a couple of simple tips that helped me on some CAN-BUS jobs that drove me apeshit. 1) Clean your battery terminals. Improper charging voltage can cause all kinds of weird things to happen. 2) Disconnect the PCM terminals, blow them out with compressed air, then reconnect them. Check for any corrosion, no matter how slight. I remember once there was a car in the shop for over two weeks that would have random things go dead for no reason. The owners were about ready to get rid of it. The cause: some slight (and I mean SLIGHT) white corrosion on the bottom of the fuse box connector. *There's a guy on LS1tech.com who is LS swapping his BMW-whatever because it would continually have CAN-BUS problems that would shut down the whole car. Superior German Engineering my ass...
Yeah, it's not surprising... a very little bit of corrosion can cause huge electrical resistance, never mind outright shorting and inconsistent behaviour. (I may only be a shadetree wrench, but I am an electrical/computer engineer). Whenever I work on that kind of stuff, even if the connectors have boots, I apply some dielectric grease for some added protection from corrosion, including on my battery terminals. And don't get me started on trailer connections... every time I use it I spray them with contact cleaner in order to keep it clean and free of water. I've been really happy with WD-40 Specialist Electrical Contact Cleaner, and keep a can in my trailer box so it's easily accessible every time I hook up/down the trailer.
When we were wrenching on the Porsches, we called them "Hansie". It was a name said in anger directed at that bastard of a German engineer in an office somewhere who though that the design/placement of whatever we were working on was a good idea, usually when we didn't have the specialty tool or hands small enough or the 3rd elbow required to work on said "superior design". Fucking Hansie.
Listen to what Flat Rate said, as well. I've been thinking about it, and the data-communication codes might be a side issue; hell, my car has some, but they don't affect the performance at all (it's an American car). Get some live data for us, then we can really help out. Anyway, I looked up the communication codes on Mitchell ProDemand, and there was a TSB about a wire getting frayed and corroding somewhere in the radiator/ grille area; they weren't really descriptive, and the picture didn't show much, but you might want to check that out, maybe pull the grill for better inspection.
Thanks for the tips gents. Gives me somewhere to start before I call in the pros. I should've mentioned that I changed the battery a few weeks ago so that could explain the low voltage code.
Nothing is harder on a computer than intermittent or unclean power. If your battery connections are bad, you’re probably getting bad power to the ECM, and it might be partially powering down then coming right back up in a weird/problem state. Here’s hoping it’s that easy!
That would be pretty awesome. There was zero corrosion but maybe I didn't tighten one post enough or something simple. Knowing my car luck though.....
My dad was a coal mine equipment mechanic. You can imagine how dirty the machinery can get as well as how much water they can deal with underground. At home anything dad worked on got either a liberal coating of dielectric grease or anti-seize
My dad was an aircraft maintenance engineer, and I learned that from him. That and the benefits of safety wire.
Had the truck towed to a local mechanic that I know pretty well. He said he had the same issue on his 2014 Corvette (same 6.2L motor) and it ended up being 3 injectors. The really cool part is that it takes special software to know which injectors and special tools to change them. So off to the stealership tomorrow morning. He said his repairs cost about $1300 but he caught it early because if the injector was stuck open, it can wash down the cylinder walls or clog the cats. If the injector was stuck closed, that cylinder runs super lean and can warp the cylinder head. This could get real expensive real quick.
How did he determine that? Seriously, I want to know what his procedure was. Because aside from either a decent scanner and/ or a digital multimeter, you don't need any "special" stuff to diagnose those injectors. Also, you DO NOT need any "special tools" to change one of those injectors. I know this, because I've done it. Basic metric hand tools are all you need.
Weird... the PCM problem I had that I posted earlier was around the injection controller... it caused one of the injectors to stick wide open on #6 cylinder (Jeep Wrangler 4.0L), and it was REALLY obvious... injector was wide open with any power to the PCM, and there was tons of smoke out of the exhaust, it smelled of gas, and I was worried more about getting gas past the rings than anything. I just got a set of noid lights to test/verify whether or not it was the injector or the PCM, and it was pretty obvious pretty fast that it was the PCM. I'd be interested to know what kind of injector failure it was... @dixiebandit69 I think he's referring to the Teflon seal installation tool for the injector, not the injector itself... it can be tricky. (Similar stuff on the BMW's I used to have... but I just used a pen to stretch it out and it seemed to work fine).
Dixie, not 100% sure. He called right as I was closing up. I thought the direct injectors were different than pre-2014 LS style injectors which are easy peasy to change. I'll ask him more questions tomorrow when I swing by there. He's a competent mechanic with several OEM certification (Just not GM) and I can't imagine him paying the dealership to do the work on his Corvette when he owns his own shop. Correct Nett, they have a special tool for the seals and they need to run a pressure test to see which injector(s) it is. https://www.gm-trucks.com/forums/topic/230137-2017-62-liter-injector-problems/ Quick google search and it sounds like a somewhat "common" issue and some people have had some luck with GM Assistance helping cover some of the costs.
Fun fact: if you view "Live data" and the fuel rail pressure suddenly drops when you stop the engine (or even a certain number of psi over a given time-frame), you've got a pressure leak. Somewhere. You don't even need a scanner to see this, just a multimeter, back-probe the wires, and have the specifications. I'd do that before replacing parts, for damn sure.