I have a 09 Yukon xl 6.2l 100% stock with stock tune. it will randomly quits, sometimes it will recover (RPMs will drop to 0 and come right back in under 1 sec, sometimes quits) driving or at idle. can't find anything wrong with it. this is a time it just quit at an idle.
I didn't see MAF in that log... would assume it would have thrown a code if it was out of whack, but just in case, does the airflow value and raw Hz signal look ok too just before/during the stall?
Does the dash/instrument cluster seem to flicker at all during the stall, or any other general random electrical oddities noticed in the vehicle?
I do see though that you logged a parameter im not familiar with "engine shutdown". Forgive my ignorance on that one; are there any instances in which you actually can see that changing from "no" to "yes"? Wondering if that is more for the hybrid applications where the ignition stays on and the engine turns off? Seems like if you turn the key to shut the engine off, the OBDII communication is also lost, so that would technically never get a chance to switch from "no" to "yes" but I might be missing something there.
Just taking a stab at it, but since any loss of power or ground or signal from a sensor or to the coils/injectors/etc on the engine that would result in a stall should be accompanied with a DTC, wonder if there is an intermittent connection on a main ignition signal from the "key", BCM, DIC, whatever tells the ECM you have the key on and want the engine running. If signal was lost there it maybe simply thinks you were turning the key off (even for a split second) and not report any errors. (Thinking along the lines of the 800,000+ cobalt, g5, solstice, hhr inadvertent engine shutoff recall). The OBDII datastream is obviously still recording though, so wondering if there would be a glitch noticeable if ignition power was "turned off" for a split second, or if it would keep picking up data.... I would be curious to see what the engine and datalog response looked and felt like if you purposely very quickly cycled the key just barely out of run then immediately back in run (like few milliseconds only if possible!), if the response was totally different in some way may rule it out at least.
Hmm, another thought... is there a parameter or flag in VCM scanner for your application for VATS/anti-theft/whatever-they-call-it-now, signal? Just like no VATS signal = no start, loss of VATS might = engine shutdown... but that should be a case where your "engine shutdown" parameter should switch to yes...
Last edited by CaudleDynamicsLLC; 10-09-2022 at 05:47 PM.
i will add the MAF to the log and run it again. can let it run for 5 min or less and the problem will show up. sometimes it throws codes, but they are random, Blind spot detection malfunction, next time might be Camshaft Position Sensors (changed it) i have all so got, stabilitrak, crank Position Sensors (changed it), the instrument panel has stopped work tell you shot it off then works fine. i have replaced all battery cables, cleaned and sanded all ground wires, added a ground from block to body, new ngk plugs, msd plug wire, replaced the ignition switch, replace the alternator and battery (they tested good but still replaced them with new ones). i just started logging with HP tuner trying to find the problem.
Last edited by thebob232; 10-09-2022 at 08:04 PM.
You should do a crank relearn procedure. And a throttle body "clean" procedure. This should help you at least get back to what's supposed to be read...
Also, make sure you don't have a mechanical issue like a vacuum leak or bad/old spark plugs, etc....
Finally, these years or pretty notorious for have too low of idle right from the factory... Lots of us Yukon guys turn up the
idle base and idle in gear base by 50-100 rpms. This tends to smooth out idle as well - And I'm referring to bone stock (no cam change)
Hmm, if other things like stabilitrak, blind spot, instrument panel, etc act up too, i suspect you probably dont have an engine or sensor issue but something more broad like one of the large bulkhead or inline electrical connectors that serve multiple systems/circuits/modules. Have any of the random DTC's been for something along the lines of Serial Communications Loss, or BUS network, or lost communication with a module?
I know this route is a pain, been there before, lot of investigative time and effort but 'tis life of the modern car diagnosing; A more general code reader that can scan body, chassis, door, hvac, etc module DTC's might be the best tool. If you can keep a list of everything that flakes out, and what code each module gives (for a hint of which circuit/wire may be affected), then (with the aid of factory service manual or some sort of online service, or just good Google-ing, to get connectors schematics and pinouts) see if there are any particular large electrical connectors that all of those affected modules' circuits have in common. Otherwise... just unplug, wiggle, and re-connect every big connector in/on/under the car you can get your hands on!
Thanks everyone for all the input. I will let everyone know what I find when I find it.
thebob232,
The plastic split loom that protects the wires in the wire harness on those models are bad about disintegrating, especially in the engine compartment with heat and chemicals. The wires will rub and either short out or corrode and cause high resistance/low voltage in circuits. May want to try shaking every thing you can put your hand on and see if you are able to duplicate your issue.
Another common issue with these models are broken motor mount. Broken motor mounts let the engine jump around and will cause wierd things to happen.
Good luck.
Also good points there. Forgot about those; my escalade had those same flaws; barely remnants of any plastic loom left underhood and two broken engine mounts at under 120k miles!Originally Posted by mechanicalmatch
The plastic protector sleeve is 80% gone. I can't find any bad wires or plugs. The only common code that says on it is B1001-46 option configuration error. I was going to get a new engine wiring harness and hope for the best. But I can't find one
Do you have an aftermarket remote start on this? If you do, maybe disconnect and temporarily return to stock to see if that may be contributing to the issue.
I'm sorry, I didn't have coffee yet. B1001-46 I would look up the troubleshooting for that code and start digging.
Factory remote start.
I can clear all codes start it and shut it off and code B1001-46 is back. I can't find much information on that code.
I was going to start changing wiring harness one by one but having a hard time finding them.
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