Engine shuts off while driving

[jfoj]

Was going to note after steering input the engine dies. I believe these vehicles have electrical steering assist, not hydralic or belt driven.

The ECM will load shed when Voltage gets low or will kill fuel/spark if the Voltage gets too high to protect modules from damage. I think the upper threshold is around 18-19 Volts.

I would suggest before going too much further is to get a decent Voltmeter (Fluke 86/87 or something decent quality with fast reaction time) with a Max and Min hold and connect to the battery first and start and run the engine and see if you can get the engine to die using the steering and not the Max/Min Voltages.

Then the next test would be to try at the output of the alternator and do the same thing. If the dealer tech has an OBDII power adapter, this might be a good place to also test Voltage behavior. You can also set up an OBDII tool to monitor the Module Voltage as well. Unfortunately the OBDII Module Voltage PID may be too slow to catch a fast reacting behavior, but it worth looking at.

Another thing just for kicks would be to load the alternator/electrical system heavily to see what happens. Heated seats and steering wheel, rear window defogger, HVAC fan on high, high beam headlights. Do these cause the engine to die, or conversely do they allow the engine not to die?

The other option is if you think the problem is steering related, pull the electric steering fuse but then turn the steering wheel to determine if the problem may be more mechanical or not related to the steering assist current draw. I do not know if these vehicles have a steering angle sensor, maybe something crazy going on there as well if there is a steering angle sensor??

Unsure if a module(s) get spiked something may protect it like a thermal fuse or for some reason the Voltage regulator is getting shorted and even while cranking the alaternator is putting out too much Voltage?

Bad connection, loose ground, too much Voltage drop could be playing into this.

Just some ideas toosed out there to make folks think outside the box a bit.

Good luck!

 

[Doubeleive]

Gonna try and replace the crank sensor and cam sensors tomorrow.

I wouldn't jump to replacing sensors unnecessarily, I would be looking for whatever is causing a excessive load. maybe when it happens disconnect the electric steering and see if anything changes. check all the bolts and grounds, etc
the sensors can be ohm tested with a meter

 

[viven44]

I wouldn't jump to replacing sensors unnecessarily

Agree with that. Don’t start a parts cannon … you are dealing with a one off problem from an electrical issue that will need deep diagnostics and troubleshooting. Something the dealer should be doing since you are under warranty, I’m all for data analysis and diagnostics and parts replacement based on a guaranteed diagnosis, but if you can’t even pull a code don’t replace parts.

Your money and your vehicle ultimately but I think I’m done with my 2 cents on this post

 

[jfoj]

No disrespect to the dealer techs, but most are not great troubleshooters as they see the same problems over and over and anyone under 40 years old probably is mostly a "code reader".

This is a highly unusual problem that standard trouble trees and diagnostic processes will not likely get you to a quick solution.

Suggest you time the "15 minute" period and see if it is really around 15 minutes or if this is just a guesstimate. Keep in mind when you remote start these vehicles, they automatically shut down in 15 minutes. While you sould see a message on the dash that gives you a few minutes notice, if something crazy is going on the 15 minute shut down may be killing the engine?

You have to think way outside the sandbox here, but also start with charging system basics, you may even need to disable the alternator for testing as well. Unforutnately removing the serpentine belt is not the best option, alternator may need to be disabled some other way.

 

[blanchard7684]

Agree with above strongly.

The dealer would have to workout something with Gm to get a tech on “ straight time” for an issue like this.

The dealer would pay the tech and then work with gm later about recouping the labor time.

This issue is definitely in this realm.

So the more specific you can get the better…which is why your own time working this is value add.

In other words, if you could give the dealer tech a description something like ( this is hypothetical):

Steering input after 15 minutes of operation causes engine to die. Voltmeter shows alternator reaching peak voltage during this episode. Then engine won’t restart until some amount of time.

Pulling steering fuse seemed to negate this issue.

Fuel, air, spark, injector pulses check good.

If the tech can’t get to a cause with this they can sure bring it to a tech support hotline.

 

[jfoj]

Forgot to ask, has your vehicle had a history of water leaks or regularly have condensation on the inside of the windsheild when parked overhight?

 

[NELLY1947]

So, just after 2 hour drive, approaching my parking my engine just shuts off, and i get a message saying restart engine. I go to restart it but it cranks and doesnt start. While waiting for the tow truck, about an hour and a half later the car starts up just fine. I drive around for a but and it shuts off again. get it towed to the dealer and they change battery sensor and do some reprogramming, i drive it out and 10 mins later same thing happens again. Dealership is useless cause they never seem to diagnose the problem when it is happening as on cold start the car starts and runs fine. So i took it back changed the fuel pump control module the next time it shuts off but that didnt seem to fix it. now i have it at an independent garage, anyone have any ideas as what it could be? Im gonna also change the crankshaft position sensor tomorrow.

2023 Yukon SLT 5.3l

It shows a 2023. Are u nog under warranty???
If yes take it to another dealer....

 

[sasso]

this morning car started up fine, this time after it’s got to operating temperature we stuck to just steering inputs and lo and behold car shuts off, and now finally it gave us an error code. See photo for more info.

For everyone saying dealership should be doing this. The dealership is garbage here. I have some off-road lights and a dc to dc charger installed and after the first non start I disconnected it all. The dealerships first action was to blame the lights even though it’s not connected. Secondly the dealership never worked on the car when it was in its non starting condition. The very first time I took it in the cold started it, saw a code for low battery and they changed a battery sensor, did no testing and released the car to me. 10 minutes later it died, I knew it was going to die cause a battery sensor does not make sense so I stayed close and on small roads cause I didn’t want the car to die on me on the freeway (Now imagine someone that has little to no knowledge about cars, they’d be driving on a major road car dies in traffic which could then cause serious harm to the operator.) This is after the service advisor told me that he is 100% sure the car is fixed.

When I suggested to them that it could be the fpcm he didn’t even know that such a part exists and he straight away dismissed me and didn’t even relay my message to the tech. The second time I took the car back in, same story the tested the car the evening before just before they shut, got it to stall and then parked it cause it was end of shift, and only the next morning did they try and diagnose it, again while cold starting and car running fine. They didn’t even try to ask what caused the car to stall, while the car is running fine they were gonna change the fuel pump. Didn’t make sense so I took the car back and gave it to an independent who works on my 16 Tahoe and that too very well.

Now waiting for parts to arrive to finally try and get this problem sorted. Will update you when I have further information

Thank you everyone for your inputs, very good to know the support and care this forum provides, even when dealerships let us down. <3

Edit: we have only one dealership

 

[blanchard7684]

@sasso

thanks for the update. glad you have something concrete to work off of.

What is the plan--change cam and crank sensor?

This code makes sense that you would get a hard start after a shutdown.

I'm interested to see if this is also causing the steering input malfunction as well.

 

[sasso]

@sasso

thanks for the update. glad you have something concrete to work off of.

What is the plan--change cam and crank sensor?

This code makes sense that you would get a hard start after a shutdown.

I'm interested to see if this is also causing the steering input malfunction as well.

Gonna start with the crank sensor first and move from there.

Im guessing the steering input is malfunctioning the crank sensor. but lets see. will update in an hour or so