Keyless entry / starting not working

Hi all,
I was wondering if anyone can give me a hand with figuring out a problem i have with the keyless entry on my project car. I have a 2007 prius and the keyless entry and start doesn't work because the vehicle had been in a bad storm / flood and got water in it. I got everything else to work in the vehicle from the hv battery cells to the satnav but i am stuck on the keyless entry.
I have changed the antennas / key / modules but stiil no success.
I would like to ask if anyone knows how to check the frequency / signal the antennas give out to pickup the key fob? Also if they are replaced with other antenna units, do the replacement units all have to have the same number on them and also do they nedd to be programmed in?
Any information would be greatly appreciated!