L322 Range Rover System Description and Operation
SECURITY
DESCRIPTION AND OPERATION
86-5-9
Infrared Receiver (Where Fitted)
The infrared receiver converts the signals from the infrared remote handset into digital messages and transmits them
to the BCU. The infrared receiver is integrated into the interior rear view mirror, with the receiving diodes installed in
the red knob on the underside of the mirror. Operation of the receiver is powered by a permanent battery feed from
the passenger compartment fusebox.
Alarm LED
The alarm LED is installed in the red knob on the underside of the interior rear view mirror to provide a visual indication
of the alarm system status. Operation of the LED is controlled by the BCU.
Alarm System Status Indications
BBUS
The BBUS is installed in the rear corner of the engine compartment, on the driver's side, on a bracket attached to the
front wing. Depending on the BCU configuration, the BBUS can be used to produce the audio acknowledgement for
arming and disarming of the alarm system as well as the audio warning after an alarm has been triggered.
The BBUS is normally operated by a permanent battery feed from the passenger compartment fusebox. An integral
7.2 V rechargeable battery powers the BBUS if it is disconnected from the vehicle battery.
The BBUS sounds when it receives an alarm or acknowledgement signal from the BCU. While the alarm system is
armed, the BBUS also monitors the battery power supply and the arm/disarm signal line from the BCU, and operates
the sounder if the battery power supply or the arm/disarm signal line is disconnected. The BCU arms and disarms the
BBUS together with the rest of the alarm system.
Once an alarm has been triggered, the BBUS cycles the sounder on for 30 seconds and off for 15 seconds, for 5
minutes or until it receives a disarm signal from the BCU. If the alarm trigger is still present, the 5 minutes of on/off
cycles is repeated a further 2 times. The alarm output from the BBUS is either a constant tone or a modulated tone,
depending on the market. The continuous tone has a nominal value of 113 dBA when powered by the vehicle battery
and 108 dBA when powered by the integral battery. The modulated tone has a nominal value of 109 dBA when
powered by the vehicle battery and 104 dBA when powered by the integral battery.
Alarm Mode
Alarm LED
Disarmed
Off
Armed
Flashes at 0.5 Hz (slow flashing)
Arming
Rapid flashing for 10 seconds maximum, then begins flashing at
0.5 Hz.
Alarm triggered
Rapid flashing for 5 minutes then continues flashing at 0.5 Hz.
Re-arming less than 10 seconds after disarming
On for 1 second
Disarming
Off
Disarming after alarm
Rapid flashing for 10 seconds then off
Emergency disarming
On for 10 minutes
Vehicle locked (alarm not coded in BCU)
On for 10 seconds
Unauthorised engine start detected by
immobilisation system
Rapid flashing until immobilisation system deactivated