You can correct something when there's a mistake or error in it. You can fix something when it's broken.

Correct: I want to correct my mistakes Fix: I want to fix the motor. or I want to fix the date or I am looking for all the possible ways to fix this unfortunate situation. = meaning setting things straight. Basically, Correct - as u might know is to correct the wrong things.. whereas fix can be either used for things.. as above or can also be used to set a time or date .. or it can also be used in correcting wrong doings in certain issues (informal usage) Hope it helps :)