Mercedes-Benz 2008 M-Class Operator's Manual page 262

Range of the sensors
To function properly, the sensors must be
free of dirt, ice, snow and slush. Clean the
sensors regularly, being careful not to
scratch or damaging the sensors, see
"Cleaning the Parktronic* system sensors"
( page 394).
!
During parking maneuvers, pay special
attention to objects located above or below the
height of the sensors (e.g. planters or trailer
hitches). The Parktronic system will not detect
such objects at close range and damage to your
vehicle or the object may result.
Ultrasonic signals from outside sources (e.g.
working jackhammers, car wash or the air brakes
of trucks) may impair the operation of the
Parktronic system.
Controls in detail
Driving systems
Front sensors
Center approx. 40 in (100 cm)
Corners approx. 24 in (60 cm)
Rear sensors
Center approx. 48 in (120 cm)
Corners approx. 32 in (80 cm)
Minimum distance
Center approx. 8 in (20 cm)
approx. 6 in (15 cm)
Corners
If the system detects an obstacle in this
range, all the distance warning segments
illuminate and you hear a warning signal. If
the obstacle is closer than the minimum
distance, the actual distance may no
longer be indicated by the system.
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