I once had one freak out because a bug splatted on the sensor, and of course everytime i drive in the snow.
I know that they were replacing the defective radar units with the same faulty sensors. I haven't heard if they have received updated shipments yet.JG - please let us know how it goes at the dealer. I've had my 18 Altima at dealer at couple of times for routine maintenance. Service tech says there is no known fix for the problem yet.