Freelander System Description and Operation
SECURITY
86-5-14 DESCRIPTION AND OPERATION
The transponder coil is located in a black plastic housing which is located around the ignition key barrel. The coil is
connected by two wires to the immobilisation ECU.
The transponder coil passes electrical energy and data at a frequency of 125 kHz to a transponder in the vehicle key,
up to a range of 20 mm (0.78 in) from the coil.
Key Transponder
Each vehicle is supplied with two vehicle keys and two separate RF transmitters. The RF transmitters are used to lock
and arm the vehicle, and for the tail door window drop function. The key head contains the transponder used by the
immobilisation system.
Key and Remote Handset
On vehicles up to VIN 242163 (EWS-3D System), each keyblade has an external waveform profile which is coded
and recorded in a BMW Group database, therefore replacement keys are only available from franchised dealers/
suppliers. The transponder contains a 128 byte EEPROM which is programmed with vehicle identification data which
is checked by the immobilisation ECU before re-mobilisation is activated. The information programmed into the
EEPROM cannot be overwritten.
On vehicles from VIN 242164, each keyblade has an external waveform profile which is coded and recorded in a
Land Rover database. Replacement keys are supplied to the dealer with the correct keyblade waveform profile cut
and the transponder programmed by Land Rover. The transponder contains a 256 byte EEPROM which is
programmed with vehicle identification data which is checked by the immobilisation ECU before re-mobilisation is
activated. The information programmed into the EEPROM cannot be overwritten.
Immobilisation ECU
The immobilisation ECU is the central component in the immobilisation system and is located behind the fascia in a
central position.
The immobilisation ECU communicates with the CCU and is connected to the diagnostic socket enabling diagnostic
procedures to be carried out.
There is no audible or visual indication to the driver of the condition of the immobilisation system.
The immobilisation ECU receives information from related systems on the vehicle and passes a coded signal to the
ECM to allow starting if all starting parameters have been met. The information is decoded by the ECM which will
allow the engine run if the information is correct. The information is on a rolling code system and both the ECU and
the ECM will require synchronisation if either component is renewed.
Depending on engine fitment, four different ECM's can be used on the vehicle. Each ECM communicates with the
immobilisation ECU using the same protocol .
The immobilisation ECU also protects the starter motor from inadvertent operation. The ECU receives an engine
speed signal from the ECM via the instrument pack. When the engine speed exceeds a predetermined value, the ECU
prevents operation of the starter motor via an integral starter disable relay.