Land Rover Discovery Owners & Service Manuals

Land Rover Discovery: Anti-theft - Active


Anti-theft - Active / Description and Operation

  1. Central Junction Box (CJB)
  2. Instrument Cluster (IC)
  3. Immobilizer Antenna Unit (IAU)
  4. Smart key
  5. Radio Frequency (RF) receiver
  6. Battery Back-Up Sounder (BBUS)
  7. Hood switch
  8. Tailgate latch mechanism
  9. Keyless Vehicle Module (KVM)
  10. Volumetric sensor
  11. Driver Door Module (DDM) (passenger side fitted with a Passenger Door Module (PDM))
  12. Driver door latch mechanism (passenger door latch mechanism is the same)
  13. Rear Door Module (RDM) (2 off)
  14. Rear right door latch mechanism (rear left door latch mechanism is the same)


The active anti-theft system monitors the hinged panels for unauthorized opening. In some markets the anti-theft system also incorporates monitoring of the vehicle interior and vehicle tilt sensing.

The active anti-theft alarm system is controlled by the following body system control modules:

  • Central Junction Box (CJB).
  • Driver Door Module (DDM).
  • Passenger Door Module (PDM).
  • Instrument Cluster (IC).

The CJB is the main controller in the system. The CJB controls the following security functions, in addition to other vehicle functions:

  • Locking, double locking and unlocking.
  • Monitoring of hinged panel micro switches and panel ajar states.
  • Volumetric sensor.
  • Battery Back Up Sounder (BBUS) or vehicle horns.
  • Passive arming and disarming.
  • Panic alarm function.
  • Smart key transponder reading.
  • Interior lighting.

Two levels of vehicle anti-theft alarm are available; perimeter mode monitors all opening panels and volumetric mode (if fitted) monitors the vehicle interior for intrusion and it also incorporates a tilt sensor to monitor if the vehicle is being moved.


Volumetric mode and tilt sensing are not available in certain markets.

The smart key provides the following functionality:

  • Unlock (central unlock or single point entry).
  • Lock and double lock.
  • Tailgate release.
  • Approach lighting.
  • Panic alarm.

The lock and unlock switches also control a 'lazy' lock and unlock feature which will automatically close or open the windows with an extended press of the applicable switch. This feature is only available in certain markets and is controlled in conjunction with the door modules.


Never double lock the vehicle with any person or animal inside.


Double locking is only available in certain markets.

The smart key contains an emergency access key. This can be used in the event of failure of the smart key or the vehicle battery to unlock the vehicle.

The driver door handle contains a concealed mechanical key barrel which can be used with the emergency key to access the vehicle. This will not disable the perimeter or interior alarm systems which will be activated when the door is opened. To cancel the alarm, the smart key must be held next to the Immobilizer Antenna Unit (IAU) and the stop/start switch must be pressed.

For additional information, refer to: Handles, Locks, Latches and Entry Systems (501-14 Handles, Locks, Latches and Entry Systems, Description and Operation).


 Anti-Theft - Active/ Description

Description The door modules provide the interface between the door latch motors, the door and latch switches and the Central Junction Box (CJB). The door modules provide door micro switch status info

 Anti-theft - Active / Operation

Operation The Central Junction Box (CJB) automatically arms and disarms the active anti-theft system when it operates the Central Locking System (CLS). On vehicles without a volumetric sensor, only t

 Anti-theft - Active / Diagnosis and Testing

PRINCIPLES OF OPERATION For a detailed description of the Anti-Theft system, refer to the relevant Description and Operation section in the workshop manual. REFER to: Anti- Theft - Active (419-01A Ant


 Front end Body Panels Engine Undershield (G1660881) / Removal and Installation

REMOVAL NOTES: Some variation in the illustrations may occur, but the essential information is always correct. Removal steps in this procedure may contain installation details. WARNING: Make sure to support the vehicle with axle stands. Raise and support the vehicle. NOTE: Loosen the bolt, but

 Seating - Component Location - Manual front Seat Adjustment

Seat forward/rearward adjustment lever Seat height adjustment lever Seat backrest recline adjustment knob COMPONENT LOCATION - ELECTRIC FRONT SEAT ADJUSTMENT Seat backrest recline motor Seat switchpack Seat module Seat cushion tilt motor Seat forward/rearward motor Seat height motor

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