Volvo 2008 S40 Owner's Manual page 151

The system is activated automatically when the vehicle is started. The indicator light in the button in the center console
illuminates.
The front park assist system is active from the time the engine is started until the vehicle exceeds a speed of
approximately 10 mph (15 km/h). It is also active when the vehicle is backing up.
Rear park assist is active when the engine is running and reverse gear has been selected.
Rear park assist
The distance monitored behind the vehicle is approximately 5 ft (1.5 m). The signal comes from the rear speakers.
The system must be deactivated when towing a trailer, carrying bicycles in a rear-mounted carrier, etc, which could
trigger the rear park assist system's sensors.
NOTE
Rear park assist is deactivated automatically when towing a trailer if Volvo genuine trailer wiring is used.
Front park assist
The distance monitored in front of the vehicle is approximately 2.5 ft (0.8 m). The audible signal comes from the audio
system's front speakers.
It may not be possible to combine auxiliary headlights and front park assist since these lights could trigger the system's
sensors.
163
06 Starting and driving
Park assist (option/accessory)
Activating/deactivating park assist
The system is activated automatically when the vehicle is started.
If the vehicle is equipped with both front and rear park assist, press the park assist button on the center console
(see the illustration) to temporarily turn off (deactivate) the systems. The indicator light in the button will go out when
the system has been switched off.
If the vehicle is equipped with rear park assist only, a message will be displayed when reverse gear is selected
showing if the system is on or off. Press EXIT to turn rear park assist off, or ENTER to turn the system on.
Park assist will be automatically reactivated the next time the engine is started, or if the button is pressed (the
indicator light in the button will illuminate).