1997 RENAULT LAGUNA remote start

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GENERAL OPERATION
Decoder Unit (BII)
This system is similar to many other immobilizer systems as it uses a transponder within
the head of the key to send its code to the immobilizer when interrogated via the immobi-
lizer ignition key barrel antenna. The code from the key is transferred to the Decoder Unit
which has the following functions:
• Decoding the key transponder signal, via the antenna coil
• Management of the engine immobilizer system by sending the received code to ei-
ther the EMS-ECM (Petrol engine) or the Coded Solenoid Valve (Fuel Cut-off valve
for diesel engines) to authorize the vehicle to be started
• Control of the immobilizer LED
• Central door locking functions (if fitted)
• Courtesy light control (part of central locking if fitted)

Multi Timer Unit (BMT)

The Multi Timer Unit has the same immobilizer function as the Decoder Unit above using
an ignition key with a transponder and an ignition key barrel antenna. The Multi Timer
Unit has the following functions (amongst others):
• Decoding the key transponder signal, via the antenna coil
• Management of the engine immobilizer system by sending the received code to ei-
ther the EMS-ECM (Petrol engine) or the Coded Solenoid Valve (Fuel Cut-off valve
for diesel engines) to authorize the vehicle to be started
• Control of the immobilizer LED
• Central door locking functions (if fitted)
• Courtesy light control (part of central locking if fitted)
Type 'I' Key Recognition Optional IR Rolling Code - Petrol/Diesel
This system can be used with or without an Infrared Remote Control, which would require
a separate control unit.
Type 'J' Coded Card instead of Key
This system is an immobilizer only, a separate system must be used to operate the cen-
tral locking, however, a Coded Card may contain a remote control transmitter for gaining
entry to the vehicle.

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GENERAL OPERATION
Coded Card
The coded card system was introduced for the latest Laguna models and eliminates the
use of 'ignition keys' and, optionally, 'door locking keys'. Instead of a key the driver has a
coded card that, optionally, unlocks the door and after insertion into a card reader, sets
self-retaining relays to supply the various systems/circuit in the vehicle (equivalent to the
ignition switch), deactivates the immobiliser to allow the vehicle to be started and unlocks
the electric steering lock. The code is a random rolling code to reduce the chances of
simulation.
The engine is started via an engine start/stop push switch, which when pushed will ener-
gize the starter. If pressed again the switch will stop the engine and removing the card
will break the retaining circuit to the main relay and the vehicle will shut down all systems
and circuits except any required to remain on, e.g. lighting circuits, hazard lights etc. The
following are the immobilizer functions:
• Decodes the signal from the card via the card reader
• Sends a signal to the electric steering column lock
• Communicates with the EMS-ECM
• Controls the immobilizer LED and the card reader light
• Communicates with the immobilizer
This system uses a multiplexing system to send data to peripheral devices, namely the
electric steering lock, diagnostic socket, EMS-ECM and the LED in the instrument pack.
All Systems

Each system has a visual indication of the immobilizer status but whether or not it has a
separate red LED to that of the EMS-ECM is dependent upon the system. If it shares and
LED with the EMS-ECM this will flash regularly when the immobilizer is active and is also
used to indicate acceptance of the security code numbers manually entered using the
door locking button. In general the following functions are indicated by the LED:
• Activation of the immobilizer
• Non recognition of the Coded Card or Coded Keys
• System fault
• Fault with the EMS-ECM immobilizer function
• Fault with the Electric Steering Lock (Coded Card only)
• Signal of entry into door locking remote control resynchronization mode (Decoder/
Multi Timer systems only)
• If a fault with the EMS-ECM immobilizer circuit occurs whilst the vehicle is in motion
the immobilizer LED will flash during deceleration and when at idle speed.

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GENERAL OPERATION
All systems have the same end function, immobilizing the vehicle until the correct code is
presented to the immobiliser unit.
Type 'A' Infrared Remote Control Fixed Code - Petrol
This system uses a combined immobiliser and central door locking control unit with a re-
mote infrared transmitter contained in the plastic keyhead. The transmitted code is fixed
and when received by the control unit receiver it will generate a door open signal and si-
multaneously pass the code to the EMS-ECM. The EMS-ECM compares the received
code against a stored code and if verified it will allow the engine to be started. This type is
for petrol only vehicles and will allow up to seven keys to be used.
Type 'B' Infrared Remote Control Fixed Code - Diesel
This system uses a combined immobiliser and central door locking control unit with a re-
mote infrared transmitter contained in the plastic keyhead. The transmitted code is fixed
and when received by the control unit receiver it will generate a door open signal and si-
multaneously pass the code to the Coded Solenoid Valve. The Coded Solenoid Valve
compares the received code against a stored code and if verified it will allow the fuel to
the engine. This type is for diesel only vehicles and will allow up to four keys to be used.
Type 'C' Infrared Remote Control Rolling Code - Petrol
This system uses a combined immobiliser and central door locking control unit with a re-
mote infrared transmitter contained in the plastic keyhead. The transmitted code is rolling
to reduce the chances of the code being captured and used to enter the vehicle. The
code when received by the control unit receiver it will generate a door open signal and
simultaneously pass the code to the EMS-ECM. The EMS-ECM compares the received
code against a stored code and if verified it will allow the fuel to the engine. This type is
for petrol only vehicles and will allow up to seven keys to be used.
Type 'D' Key Recognition - No Infrared Remote - Petrol
This system uses key recognition only with no remote control of entry. A transponder in
the keyhead reacts to a transmitted signal from a coil wrapped around the ignition key
barrel. If the transponder code is the same as the stored code the EMS-ECM receives a
signal to allow the engine to run. This type is for petrol only vehicles and will allow up to
seven keys to be used.