all my warning lights coming on after driving, even the at oil temp. took it into the dealer twice and they say it is fine, nothing wrong
2015 Forester Premium with EyeSight here. 32000 on the odometer.
I had that experience only once, after one of the wheel bearings were changed. I was driving very slowly (abt 5mph) in the school parking lot, just about to park, had to take 1/4th circle turn and all lights lit up. There was absolutely no difference in how the car drove for those 1000 or so ft. I had a meeting with the teacher so had to turn the car off, thinking if it lights up again, I will stick the OBD scanner and read the code before pulling it out. But it never happened again.
So my advice to you would be, get https://www.amazon.com/BAFX-Products-Bluetooth-Diagnostic-Scanner/dp/B005NLQAHS. Its super cheap today, usually it runs $30, today its $18. Do NOT buy those other cheapo stuff, they do not work. This one does, with our vehicles.
If you are android user, get Torque app (free version) or check other apps here https://www.obdadvisor.com/best-obd2-app/
Try it out once or twice when the car is idling to understand how it works and leave the scanner in the vehicle. When trying out, the car should not show any codes. Check youtube videos to understand how it shows up on the screen. Put check engine light code in search box. If it does show any codes, go to the trustworthy mechanic first and then dealership (if required).
If this happens again, pull over, leave the vehicle running, stick the OBD scanner to OBD port (under the steering wheel, above the brake pedal, stick the scanner upside down, BAFX sticker down) and scan for codes. Take the screenshot of all codes and then go to the dealership or trustworthy mechanic. If you are interested, share the screenshots here too (or subaruforester .org) Other folks will try to help. I personally want to know as well because when I started the car up again after the meeting, everything was hunky dory. I even made multiple rounds of that part thinking the wheel must have turned in some weird fashion and new bearings triggered warning. There is a ring within the wheel bearing assembly that is a sensor for ABS and my mechanic mentioned that could be the possible trigger.
I am sorry, if the directions sound too didactic. My wife drives this vehicle and I am writing as if I am telling her. Her job is just to drive. She has absolutely no idea of anything about the car. If you do, then ignore that part.