My 2019 Equinox has an issue where while sitting still it will shut off. I'm not talking about the auto-stop, it literally shuts off. When this happens everything inside stays lit up. The dash display is on, the control center is on, etc. The Start/Stop button is still lit up green. However, the RPM gauge drops to zero, well below the auto-stp indicator, obviously. The engine light is on and I'm getting single code, which I don't have handy at the moment, that's says the computer lost connection to the battery sensor. I replaced that sensor and the problem seemed better for a bit. Now, it's doing it again.

When this happens, the dash saves 'Battery Saver Mode Activated'. If I push the starter button the engines cranks and cranks but does not start. If I disconnect the hot battery cable, it resets everything. The car will start and drive fine. Then, it does it all over again at random. It may go three days without doing it, then it'll do it three or four times back to back. It only does this when the car is stopped. It does not do it while moving down the road.

Could this be a battery or alternator issue? They both test as fine, but that doesn't mean anything.

 

It wouldn't hurt to take the battery loose and clean the terminals. I've got an old '97 Ford Aerostar that every year or so, when I go to start it, I hear a snap and everything goes dead - even the dome lights! There is no corrosion around the battery or the cables - I keep them covered with dielectric grease. The battery still has posts to attach the cables. I loosen the cables up so I can twist them back and forth, retighten them and everything's good to go for another year or so.

Make sure the battery ground wire is making a good connection (at both ends).

 

The problem persists after replacing the Battery Sensor, and cleaning battery posts. What I now know is that if I am out on the open road where the RPMs stay up around 1500 to 2000 I don't have a problem. I can stop and start at stop signs, crossroads. Etc. without an issue. However, when I get in town and I'm easing around where the RPMs don't get above 1000 to 1200, I have this problem. If I shift to park and keep the RPMs up at redlights, stop signs, etc. I don't have an issue. But, if it idles at one stop for more than a minute or so, it shuts off and loses power at the next stop if there hasn't been much higher RPM time between.

Any ideas?