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Engine completely shuts off while driving then turns back on

dome33

New Member
Joined
Jan 16, 2018
Messages
3
Location
Olathe, KS
Recently I have been having issues with my 2011 Avalanche.  While driving down the road the following will happen: truck dies and I loose all power (steering, brakes, dash), & the door locks cycle.  It's almost like I just shut the truck off while driving.  Within a second or two the truck resumes driving like nothing happened without having to do anything.  I don't have to restart the truck or shift into neutral and i never get any error codes.  This has happened 3x in the last week with every occurrence being about 20 min into the drive.  It's happened while cruising, braking, & accelerating.  Not sure what to do and hate thinking of taking it in and spending several hundred dollars to not get any resolution.  Truck has no modifications & 157k on it.  Anyone have an idea or experience this? 
 
My first guess is fuel pump cutting out. But i am in no means a mechanic

Truck restarts its self?
 
The engine dies....
you coast a bit
Then engine RE-starts on its own?

Gremlin city

Any check engine light?
 
YGMN - Yes.  The vehicle acts like if you would completely shut it off, but the key is in the run position.  Without even touching anything the car will turn back on and resume driving like nothing happened within 1-2 seconds.  No error codes, no check lights.  Just received a call back from the shop I dropped it off at to run diagnostics and they plugged it in and ran it for a while checking every sensor.  They didn't see any lag or misses for any sensors and said the fuel pump, alternator, and the bottom of the Fuse Box look good with no signs of an issue.  They mentioned a recall from a few years ago with gm keys malfunctioning and suggest that I drive around with my second key to see if the issue comes up still (attempt low hanging fruit first before ripping apart).  I'll report back in a week to see if that works, but until then any suggestions or ideas are greatly appreciated. 
 
I have not heard of this key thing....

I say check wiring for mice that were hungry and got to chewing.
 
I don't think "key problems" have been around since the days when they put a computer chip in the keys as an anti-theft device. There have been some bulletins out about ignition problems and how the ignition itself gets worn out and needs replacing. Some say the wearing out is escalated by big heavy key rings and suggest when ignition is replaced to limit the amount of stuff on the key ring. (I hopefully trained my whole family to use a "pull apart" key chain to have house keys, fobs , and other stuff separate from ignition key so there would not be heavy weight on ignition.) So far so good for us.
Old threads have shown where ignition problems can show as many forms of electrical gremlins.....

Good luck in finding a solution.
 
Sorry for not replying to anyone for some time.  But I wanted to make sure my issues did not reoccur while trying a different key.  It has now been about 3 weeks since I've switched the keys I've been driving with and I have not had the issue or any of the symptoms come up again since doing it.  This is the craziest thing to me too, but it appears that my previously used key went bad or caused some sort of issue with the computer.  I'm at a loss of words, but thankful so far that it's not some computer/electrical gremlin wrecking havoc.  Thanks for everyone's input. 
 
CHEAP FIX FOR SURE!
 
My 2011 has been doing the exactly the same. The problem was the electrical part of the ignition switch. My friend who owns a mechanic shop is the one who told me about this problem and changed the switch for me. He told me to only use AC Delco  switch as it has better contacts than aftermarket switches,I ordered mine at Oriellys Auto Parts for 27.99 overnight. The other possibility if your gauges go haywire and power locks cycle over and over would indicate a defective battery ground cable.
 
Just an update on the same problem I had as the original post. After I wrote my response the Avalanche started doing it again so I changed the following as advised by lead mechanic for large GM dealership. Seems to solved problem, I changed the connector on the ground wire for the ECM, (the original connector didn't look bad) I used gold plated crimp connector from auto parts store but was told by Gm line mechanic to solder the terminal to the wire, The location of this wire goes to the front part of the chassis on the right side where the radiator mount is and your battery cable mounts to chassis. Take sand paper and clean mounting spot to bare iron He also told me to use #10 wire and connect one end to this mount with ring connector soldered and run other end up to negative terminal on engine where other battery cable hooks. So far so good! Hopes this helps anyone out there having similar problem. You have to take off the right tire and fender well cover to get to the spot where wires connect to chassis.
 
Love the follow ups! Thanks for taking the time to help the next guy/gal.
 
Sorry took so long to reply but life has been crazy and have been working 7 days a week since beginning of sept. 2020. The problem raised its ugly head again in oct. 2020. Due to lack of free time I took it to the Chevy dealership as soon as problem started again and they replaced the fuse and relay block ( where all your fuses and relays are plugged in) mounted under the hood on the drivers side. No problems since Oct. 2020 and had the cruise control repaired at same time which was a brake pressure sensor, Just over 500.00 for both repairs
 
Well I thought all what I did fixed my problem but it started happening again. I decided to have the ECM changed and now I know the problem is fixed. We went on a 1200 mile trip and several several trips to work and It's run perfect. On long trips before it would do it several times and the transmission also shifts a lot smoother.
 
Well I thought all what I did fixed my problem but it started happening again. I decided to have the ECM changed and now I know the problem is fixed. We went on a 1200 mile trip and several several trips to work and It's run perfect. On long trips before it would do it several times and the transmission also shifts a lot smoother.
Just to put this out there. Had this happen to me on another vehicle way back when. Vehicle would lose all power then regain it. Took it to everyone and no one could figure it out because it would not do it for them. Funny how little things can be so complicated. I Finally found it myself. One of the bolts on the starter had loosened and the wire going to it was a round connector which bounced a little when the bolt loosened. When it was not touching the metal the vehicle lost ground and along with all power. Fix was merely tightening the bolt. Not sure that this applies to the avalanche but in a complete loss of power situation you may very we have a ground problem.
 
Just to put this out there. Had this happen to me on another vehicle way back when. Vehicle would lose all power then regain it. Took it to everyone and no one could figure it out because it would not do it for them. Funny how little things can be so complicated. I Finally found it myself. One of the bolts on the starter had loosened and the wire going to it was a round connector which bounced a little when the bolt loosened. When it was not touching the metal the vehicle lost ground and along with all power. Fix was merely tightening the bolt. Not sure that this applies to the avalanche but in a complete loss of power situation you may very we have a ground problem.
Reading your issues my 07 LT avalanche did the same thing to me. I had installed a heat shield for the starter cable.
Soon after the truck would shut off everything while driving, luckily it kept rolling & didn't cause a wreck.
I found the battery/starter cable/ conductive heat shield, was shorting out to frame/ground. Somehow overloaded ecu temporarily shutting off everything.
Also the grounds can get corroded I went ahead and unbolted all grounds cleaned with wire brush dremmel tool making sure good clean meatal to meatal contact, then sprayed battery terminal protectant on areas.
Also made sure heat shielding no longer touched power lines anywhere.
 
Since I changed my ECM I have not had anymore problems with my Avalanche. I have put almost 20,000 miles on it and have had zero problems since, but thanks for the suggestions, It has been an arduous journey.
 
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