Can you run it through a diagnostics and see what error code you get? That may help narrow things down. Some of the items work off resistance so having water in a connector or part would change the resistance of that item and may throw it into limp mode.
1. Turn ignition to off
2. place tranny in nuetral
3. put on parking brake so the quad does not move.
4. Press both shift buttons (up and down), and hold them in, while turning the key to on. Make sure the N appears for gear position. Release the buttons.
5. wait 5 secs,and then press both the switches again.and hold them in for at least 3 seconds, then release the switches.
The codes should flash if there are any.
To delete an old code, do the above and when the code appears, that you want to delete, press the switches.