Lexus CT200h Owner's Manual page 217

Rain-sensing windshield wipers (if equipped)
When "AUTO" is selected, the wipers will operate automatically when
the sensor detects falling rain. The system automatically adjusts wiper
timing in accordance with rain volume and vehicle speed.
When "AUTO" is selected, the sensor sensitivity can be adjusted as fol-
lows by turning the switch ring:
Type A
CT200h_U (OM76040U)
2-3. Operating the lights and windshield wipers
OFF
Rain-sensing
operation
Low
operation
High speed wiper
operation
Temporary operation
2
wiper
speed wiper
217