Suppose someone is suddenly driving, they see no warning lights and they suddenly break down.
They inspect their engine and all everything seems fine. The car also starts up again and the problem doesn't repeat.
What might be the cause of something like this? As far as I can see for a car to breakdown it usually has a direct cause e.g. high temperature. Is it possible a car can break down in the way I have described, start up again and not repeat the problem for a while?
Yes, this is definitely possible. One possible cause is poor electrical contact somewhere. Modern cars are relying on electronics, and therefore, temporary contact failure of the electronics could cause exactly the issue you're describing.
I remember having electronic problems on an old 1989 Opel Vectra. It didn't however stop the car engine running, it just resulted in poor power, which seemed like the engine was running on 3 cylinders.
I also once had a loose wire to the ignition coil. It stopped the power to the engine when in motion, and to resume driving, I had to re-connect it. Now, could the wire be partially loose, so that it starts to work automatically? Perhaps.
I also remember that the same 1989 Opel Vectra had a problem with the ECU relay. The ECU relay caused the car to occasionally fail to start, but then after a while it started just fine. It was marginally working. Fortunately, it never failed while in motion.
So, what you describe is absolutely possible. The ECU relay and the loose ignition coil wire didn't result in any warning light.
Edit: and even newer cars rely on software far more than the old 1989 Opel did. So, a bug in the software that occurs only in some very specific rare circumstances could cause the issue. Also, cosmic rays can flip bits in the RAM. I at least hope car manufacturers are sane enough to use error correcting RAM, but then again a strong cosmic ray could flip several bits.
Earthing issues can do it, as the potential charge grows in the engine, to the point that it loses power and switches off. Turning the engine on again makes it work, because the charge has gone.
Had that on a car many years ago, and just a few months ago on sons car. Solution is to check all engine grounds.
If the problem only happened once then there is no problem. No matter what caused it if you can not duplicate the problem then there isn’t one.
