See also:

After refilling diesel exhaust fluid
Incorrect fluid Incorrect fluids After refilling with the incorrect fluid, e.g., antifreeze for windshield wiper fluid, do not start the engine because this could result in a fire hazard. ...

Activation/deactivation
Press the button. ...

Switching off automatically
The system switches off and the LED goes out: After approx. 160 ft/50 m when driving forward. Above approx. 22 mph/36 km/h when driving forward. Switch on the system again if necessary. ...