Complete Electric Failure With Other Symptoms

Greetings -

I'm a new member but a long-time reader. I know that the transient complete loss of all electrical power has been discussed here, and I have searched the site for symptoms similar to mine.

My 2012 Chevrolet Suburban LT 4WD vehicle is in good repair and has a steady maintenance schedule. The battery is newer and recently tested. Outside of the described issue, occurring with increasing regularity, my Suburban runs well.

The symptoms:

I drive the truck for varying distances without trouble. I then park the vehicle and turn off the ignition. Upon restarting the engine, I can drive for a few hundred yards before the headlamps flicker: the engine sputters, the transmission "slams," causing bucking, and all electric power goes off. Turning the key has no effect. The door locks may go up and down on their own, and the needles on the gauges jump without any power coming back on. After three to five minutes, the power returns, and there are no drivability issues upon starting the engine. Upon parking the Suburban and allowing the engine to go cold, the engine will start, allowing me to drive for varying distances before the cycle described repeats itself.

No trouble codes are lodged in the system.

I checked all cables, grounds, connections, and electric components. One note is that after losing and then regaining "all" electrical power, the digital clock retains the correct time. I reviewed all existing Technical Service Bulletins (TSB) for the 2007-2014 model years without finding much related information. The sole pertinent note described some of the symptoms occurring because of a loose or damaged automatic transmission 16-pin connector. This was not the case in my situation.

I don't expect any replies, as several other posts on this issue list various possible solutions. I am only submitting this because some of my Suburban's conditions are unique. At this point, I believe my options are exhausted, so I will have to turn to a dealer$hip for vehicle diagnosis. I will post any information that they might give to me.

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

This is an interesting case for sure. When you say that you found no codes with your scanner. Are you using a quality bi-directional scanner, capable of digging deep into the truck's electrical systems? It would seem to me that this issue would trigger one or more codes.

sounds like a bad connection to me.

I know it sounds weird, but check your battery terminals first. they should be tight. as in can't turn them with 2 hands trying very hard tight.

I don't know how much of a diy mechanic you are. but if it was mine, I'd remove the big power wire off the back of the alternator and tape it up, so it can't short out. at that point the truck will be running off battery only. and then start it, and start pulling and moving around the power and ground cables. any issues and the truck should stall out quickly without the alt to keep it running.

hopefully if it died, you'll know what wire you moved when it happened and help you search for a bad connection.

No codes with a basic code reader, or have you done a check with a more professional-level diagnostic tool? There are other layers of codes that won't be shown on a basic scanner.

since this is a intermittent issue, I would carry around a scanner that can read body codes and a volt meter.
then when the devil rears it's head, scan the whole system with the scanner and note what it shows, my guess is multiple errors
then start checking voltages and ohm's starting at the battery post's and move from there to the big fuse, larger engine grounds, then to the fuse box.
either of those troubleshooting technique's "may" point you at something.
you could also ohm test the obd port when it happens and see if the lan is intact or if the ohms are high, this may point to a faulty module that shorts when heat soaked.
a shorted module can mess up the whole network.
basic voltage/ground test
and a more advanced network ohm test