and is currently monitoring the
vehicle angle. b. If the tilt sensor
detects a change in the vehicle
angle when DWA is armed, the NG
signal is switched to inform the GM
V to activate the siren.
When the tilt sensor receives the
STDWA signal from the GM V, the angle
of the vehicle is memorized and
monitored by the solid state electronics.
Once armed, if the angle changes, the
tilt sensor provides a switched ground
signal to the GM V to activate DWA.
Interior protection (UIS)
The combined ultrasonic transmitter and
receiver in UIS monitors the vehicle
interior for motion.
The UIS is mounted in the center of the
headliner panel even with the door (B)
pillar. Due to the design of the vehicles
interior, the sensor is unidirectional and
must be installed in the proper direction
to ensure proper operation of the system
(trim cover ensures directional
installation).
Every time the DWA system is armed
(STDWA signal), the sensor adapts to
whatever objects are stationary in the
interior. The sensor emits ultrasonic
waves in a programmed timed cycle. It
receives echoes of the emitted signals.
The UIS amplifies the received sound
wave signals and compares them with
the transmitted waves. The UIS also
checks the incoming echoes for
background hiss (wind noise through a
Central Locking and Anti-Theft
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Summary of Contents for 1999-2005 M3
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