[Dave at Pelican Parts]

I don't know enough about error codes to say anything about those, but the lights going wonky and the tach going off an on point to a power or ground problem. Have you done anything like, say, dismount your tach to install an aftermarket cell phone holder? (Something that I may or may not have personal experience with...)

It is also possible that something like your battery connections have gotten flaky.

--DD