I'd guess more than one of those are related to the same fault Johnny. Check all connections are tight, wiring isn't damaged and earths are secure. Then reset the ECU, drive it and see if a fault returns.
code 12 can be, ignition, starter and ecu i believe, so have a go through anything related to that....like jay said, grounds, you can get a code 12 if you have a bad ground on the ecu...
