A więc instrukcja mówi tak, czyli dokładnie potwierdza przypuszczenia Millerka Przy czym należy pamiętać, żeby dobrze umyć szybę w okolicach sensora przed wykonaniem kalibracji:

RAIN SENSOR REINITIALIZATION SETTING

Caution

• If the initialization is performed again with water or dirt on the windshield, the rain sensor may not
  operate normally. Before performing the rain sensor initialization again, remove water and dirt
  from the windshield

Note

• When the ignition switch is turned to the ON position after replacing the rain sensor with a new one, the
  windshield condition is verified and the initial setting is stored.

• Perform the initial setting again in the following cases:
  — The windshield is replaced and the rain sensor is reused.
  — The auto wiper system operates incorrectly.

1. Remove water and dirt from the windshield surface.
2. Switch the ignition to off.
3. Turn the windshield wiper switch to the AUTO position.
4. Within 10 s after turning the ignition switch to the ON position, turn the windshield wiper switch from the AUTO
to the OFF position for 5 times and return it to the AUTO position.The windshield wiper will operate once at
low speed when the reinitialization setting is performed correctly.

Caution

• If the operation is too fast, the windshield wiper switch position cannot be detected and the initial
  setting may not be performed. Operate the windshield wiper switch for one cycle
  (AUTO->OFF->AUTO) per 1 s.