When Ignition Switch Is Turned ON with Front Wiper Switch Turned to INT Position, Front Wiper Operates though There Are No Water Drops

Check rain sensor detection area of windshield for dirt such as greases.

OK or NG 

1. OK: Calibration malfunctions. Refer to "CALIBRATION PROCEDURE OF RAIN SENSOR ".
2. NG: Clean rain sensor detection area of windshield fully.