Towing A Trailer; Limits Of The Ultrasound Measurement; False Alarms - BMW 116i 2011 Owner's Handbook Manual

System limits
Also monitor the traffic situation
PDC is no substitute for your personal as‐
sessment of the traffic situation. Also monitor
the traffic situation around the vehicle by ob‐
serving it directly. Otherwise, there is a danger
that accidents might occur due to other road
users or objects located outside of detection
range of the PDC, for example.
Loud sound sources outside or inside the car
can drown out the PDC signal.◀
Avoid driving fast with PDC active
Avoid approaching an object at speed.
Avoid moving off at speed while PDC is not yet
active.
Due to physical conditions the system could
warn when it is too late.◀

Limits of the ultrasound measurement

Detection of objects might not be possible if the
physical limits of the ultrasonic measuring prin‐
ciple are exceeded, for instance by:
▷ Trailer noses and hitches.
▷ Thin or wedge-shaped objects.
▷ Low objects.
▷ Objects with corners and sharp edges.
Low objects already indicated, such as kerbs,
may enter the sensors' blind areas before or af‐
ter a continuous audible signal is given.
Higher, protruding objects such as ledges may
not be detectable.

False alarms

Under the following conditions, PDC can issue
a warning although there is no obstacle in the
detection range:
▷ In heavy rain.
▷ If the sensors are very dirty or covered with
ice.
▷ If the sensors are covered with snow.
▷ On rough road surfaces.
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▷ In large, rectangular buildings with smooth
walls, for example underground car parks.
▷ Due to dense exhaust gas.
▷ Due to other ultrasonic sources, for example
sweeping machines, steam-jet cleaners or
neon lights.
The functional disruption is reported by an
alternating continuous tone between the
front and rear loudspeakers. As soon as the
disruption by other ultrasound sources is no
longer present, the system is fully functional
again.
▷ If the cover of the trailer tow hitch is incor‐
rectly seated.

Towing a trailer

The rear sensors are unable to perform any
meaningful measurements. They therefore do
not switch on.
A Check Control message is displayed.
Automatic activation
While the engine is running, engage transmis‐
sion position R.
Switching off automatically
System switches off and the LED turns off:
▷ When the vehicle is moving forwards after
approx. 50 m, 160 ft.
▷ When the vehicle is moving forwards over
approx. 36 km/h, 22 mph.
If required, switch on the system again.
Switching on/off manually
Press the button.
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