Did my car just have a brain Fart

[Scoobysn7x]

Got into my car (Astra 2.0 CDTI Auto) to drive to the shop on my lunch, when I turn the car on nitove the AC fans went to full blast like I'd pressed the auto button, but I hadn't. I drove up the steepish hill out of my work exit, pulled out the junction and the engine just died, no power loss dials etc were still on but the engine just stopped, and Serveic vehicle soon message appeared on the dash. I know this generally indicates a fault, so I turned the ignition off and back on the car started without issue and didn't display any serveice vehicle now message, and drove absolutely fine to the shop and back  (couple of miles). When my I got back to the car park I read the codes on the ODBii code reader I have and it found no fault codes?!?.

So I have a few questions

1. once the SVS message appears does it normally stay on until the code is read and cleared, or will it clear with a stop/start of the ignition?

2. Could the car have just had a brain fart?!

Any advice welcome