Help please any and all info would be helpful

Ok so this is my first hybrid car ever knew they'd make a comeback years ago. But to the point I know the high volt battery is bad ive drove it now a month and a half figured a few tricks on keeping it rolling but recently I ran a scan and popped up a c3000 code on top of a p2000 which I figured because they are linked but a p1018 showed up as well my question is all three tossing bad codes due to one of them. Note cats have been cut and replaced the guy whom welded them back didnt do a good job and it leaks. Can this be my whole problem with the error codes if so I'll redo them myself