It’s a good skill to know so you don’t get ripped off. You can find the most likely culprit and look up the book time and parts cost. Then go to the mechanic and don’t tell them you know. Just say the light is on. If they come back with some wild price for the issues, then you can tell them to put the car outside and you’ll come pick it up.

When I used to be a professional mechanic I solved many issues by simply reading the manual after checking codes. My library has access to the Chilton online manuals for free, there’s also google. I’ve also diagnosed issues by reading Amazon reviews for parts after reading codes.