Water can become a problem with the electronics if the car has gone through water deep enough to cause the wiring harness to be submerged, or the other instance would be if the water was salty or brackish. If your car is still under warranty, Nissan should cover the repair unless they can prove that it was operator error, such as driving into water too deep, or intentional abuse of the vehicle. I live in the states, so I the warranty coverage may be different.
Good luck