Land Rover Discovery Owners & Service Manuals

Land Rover Discovery: Central Door Locking System - Automatic Modes

The Central Door Locking (CDL) system features automatic modes to control the vehicle entry points, and provide protection for the system components.

The CDL system incorporates the following automatic modes:

  • Mislock mode
  • Speed dependent locking mode (if programmed)
  • Crash unlocking mode
  • Repetition blocking mode
  • Lockout protection mode
  • Automatic relock mode (if programmed)
  • Transport mode.


A mislock occurs if the Central Junction Box (CJB) receives an external lock or double lock request when door, tailgate or hood is ajar. To indicate a mislock the CJB sounds the vehicle horns for 100 milliseconds

If a mislock occurs due to an external lock request when a door, tailgate or hood is ajar, the CJB will not carry out a lock request on any access points.


When speed dependent locking is enabled the CJB will internally lock all the doors when the vehicle speed exceeds 8 km/h (5 mph) with all the doors closed and the engine running. When the vehicle is stationary and an interior door handle is operated, all doors will unlock.

Speed dependent locking may be enabled or disabled by the dealer using the Land Rover approved diagnostic system.


With the ignition in power mode 6, if a crash occurs that causes deployment of the air bags, the CJB will unlock all of the doors. The CJB is informed of the crash by a status message issued from the Restraints Control Module (RCM) on the high speed Controller Area Network (CAN) powertrain systems bus. The message status changes from 'no crash' to 'crash'.

The CDL system will also perform crash unlocking mode if a 'no crash' status message is not received from the RCM every 500 milliseconds.


To protect the CDL latch motors against system misuse, the CJB incorporates repetition blocking to limit the maximum operating rate of each latch motor. The lock motor in each door latch also incorporates thermal protection.

Central Locking System Motor/Actuator Operating Parameters

Central Locking System Motor/Actuator Operating Parameters

Central Locking System Motor/Actuator Operating Parameters


The vehicle is not able to be locked using any CDL switch if any door is open.

If an internal lock request is received from of the CDL lock switches, the CJB will CDL lock the vehicle and then CDL unlock the vehicle if any door is open.

If a front door is open and the open door CDL lock switch is operated and held in the locked position, the open front door may remain in the locked state. When the open door is subsequently closed, the CJB will CDL unlock all doors.


Automatic relock prevents accidental operation of the smart key switches that will unlock and disarm the vehicle.

When the CDL system is unlocked using the smart key and a door or tailgate is not opened and the smart key is detected by the Low Frequency (LF) antenna within 1 minute, the CJB will automatically lock or double lock the vehicle again, depending on the previously locked mode.


All new vehicles are delivered from the factory in transport mode. Transport mode inhibits a number of electrical systems and features to reduce quiescent drain from the primary battery during delivery. When the vehicle is in transport mode TRANSP' is displayed in the Instrument Cluster (IC).

Single point entry is enabled and global locking and unlocking using the smart key is disabled.

The speed locking mode is also disabled, but crash unlocking mode remains enabled.

To remove the vehicle from transport mode, the Land Rover approved diagnostic system must be connected during the Pre-Delivery Inspection (PDI).

For additional information, refer to: Introduction (101-01, Description and Operation).


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