Discovery 2. Manual - part 748

ALARM SYSTEM AND HORN

DESCRIPTION AND OPERATION 86-4-19

The volumetric alarm can be disarmed by unlocking the driver's door with the key or the handset, depending on
system configuration.

NOTE: The “only disarm with key if locked with key” configuration prevents the alarm from being disarmed by
unlocking the vehicle with the handset if the vehicle has been locked by the key. In this situation the EKA code must
be entered to disarm the alarm.

In order for the alarm to trigger, the following conditions must be met:

Volumetric alarm armed.

Volumetric sensors triggered.

Once triggered, the alarm will remain triggered for 30 seconds before resetting.

Super locking
Super locking prevents the use of the interior door handles to unlock and open the vehicle doors. This prevents the
doors from being opened if the window be smashed in an attempt to gain access to the vehicle.

There are four configurations for super locking:

No super locking.

Super locking on single handset press only (no key activated super locking).

Super locking on single handset press or single key turn.

Super locking on double handset press or double key turn.

To super lock, press the lock button on the handset once or twice within one second depending on system
configuration. In some configurations, it is also possible to super lock the vehicle using the key in the driver's door.
This also may require one or two turns of the key in the lock direction. If two turns of the key are required to activate
super locking, the two turns must occur within one second of each other.

In order to super lock the vehicle, the following conditions must be met:

All door are closed.

The ignition is off.

The fuel cut-off switch is not tripped.

Partial arming
Partial arming allows protection of as much of the vehicle as possible if the alarm is armed with one or more doors or
the bonnet open.

Partial arming allows the vehicle alarm to be armed even if the following conditions exist. When the bonnet or door is
closed, the BCU activates the perimetric alarm and the volumetric alarm after 15 seconds have elapsed:

The bonnet is not closed: If the bonnet is open when the alarm is armed, the BCU activates super locking and
volumetric sensing. In this condition, the alarm enters a partially armed state. All other functions of the alarm are
active and the BCU monitors the bonnet for a change of state. If the bonnet closes, the system is completely
armed.

The passenger door, a rear door or the tail door is not closed: If a door is open when the alarm is armed, the BCU
does not activate super locking or volumetric sensing. In this condition the alarm enters a partially armed state.
All other alarm functions are armed and the BCU monitors the open door. If the door closes volumetric sensing
and super locking become active.

Failure of a door latch switch: If a short circuit in the door latch switch occurs, the BCU presumes the door is not
closed. In this situation the BCU does not activate super locking or volumetric sensing. All other alarm functions
are armed.

Damaged wiring harness: If a short circuit in the wiring harness for the door latch switch occurs, the BCU
presumes the door is not closed and does not activate super locking or volumetric sensing; all other alarm
functions are armed. If an open circuit in the wiring harness for the door latch switch occurs, the BCU presumes
the door is closed and arms the alarm as normal.

ALARM SYSTEM AND HORN

86-4-20 DESCRIPTION AND OPERATION

Mislock
Mislock alerts the driver that a failed attempt has been made to lock the vehicle because of the doors or the bonnet
not being fully closed.

There are six audible configurations for mislock:

No audible warning.

Alarm sounder.

Vehicle horn.

Alarm sounder and vehicle horn.

BBUS.

Alarm sounder, vehicle horn and BBUS.

When a failed attempt has been made to lock the vehicle, the audible warning device is switched on for 50 ms and
off for 200 ms. The BCU allows the audible warning device to operate 3 times.

Passive immobilisation
Passive immobilisation prevents the vehicle from being started unless the authorised key is used to start the vehicle.

There are only two configurations for passive immobilisation:

passive immobilisation not active

passive immobilisation active

When the ignition is switched off, the vehicle remains mobilised for up to a maximum of 5 minutes. If however the
driver's door is opened, after 2 minutes 30 seconds, the vehicle remains in a mobilised state for a further 30 seconds.
When the timer in the BCU has expired, the vehicle is immobilised.

Once the ignition is switched on, the BCU transmits a coded signal to the ECM. If the coded signal does not
correspond to the programmed code in the ECM, the ECM is inhibited and the BCU inhibits the starting circuit.

In order for passive immobilisation to occur, the following conditions must be met:

Driver's door closed.

Fuel cut-off switch not tripped.

Key not inserted in ignition.

Passive remobilisation
Whenever the vehicle is immobilised, passive remobilisation of the engine occurs when the ignition is switched on,
allowing the vehicle to be started.

There are three configurations for passive remobilisation:

Passive immobilisation not active.

Passive immobilisation active.

EKA with super locking on receiving good passive remobilisation exciter coil signal.

The BCU controls the passive remobilisation exciter coil (located around the ignition barrel) to generate a magnetic
field which causes the handset to transmit a remobilisation signal. The BCU receives the signal and allows the vehicle
to be started. If a valid signal from the handset is not received within one minute of the ignition being switched to
position II, the BCU stops the passive coil from generating the magnetic field.

ALARM SYSTEM AND HORN

DESCRIPTION AND OPERATION 86-4-21

Emergency key access
If the handset fails to operate, the engine can be remobilised by using the key to enter a unique four digit Emergency
Key Access (EKA) code.

There are three configurations for emergency key access:

EKA not active (no immobiliser fitted).

EKA active.

EKA with super locking on receiving good passive remobilisation exciter coil signal.

The code is recorded on the security information card and is entered as follows:

1 Using the key, turn the driver's door lock to the UNLOCK position and hold in this position for at least 5 seconds.

An audible warning is then emitted to indicate that the body control unit is ready to accept the code. Return the
key to the centre position. It is now possible to use the key to enter the separate numerical values of the four
digits that make up the EKA code.

2 Enter the first digit of the code. If the first digit is 4, turn the key to the UNLOCK position 4 times. Ensure the

key is fully returned to the centre position after each turn of the key.

3 Enter the second digit of the code. If the second digit is 3, turn the key to the LOCK position 3 times. Ensure

the key is fully returned to the centre position after each turn of the key.

4 Enter the third digit of the code. If the third digit is 2, turn the key to the UNLOCK position twice. Ensure the key

is fully returned to the centre position after each turn of the key.

5 Enter the fourth digit of the code. If the fourth digit is 1, turn the key to the LOCK position once. Ensure the key

is fully returned to the centre position after each turn of the key.

6 Finally, turn the key to the UNLOCK position and back to the centre position, a double bleep will indicate that

the code has been entered correctly. A single bleep indicates that the code has been entered incorrectly.

Then, before opening the door, wait 5 minutes for the alarm and immobiliser to be de-activated. During the 5
minute wait for the alarm and immobiliser to be de-activated, the alarm indicator LED in the instrument pack
continues to flash (one flash every 2 seconds). DO NOT OPEN THE DOOR OR ATTEMPT TO ENTER THE
CAR until the full delay period has elapsed.

When the 5 minute wait has elapsed, the alarm indicator LED stops flashing. Immediately open the door, insert
the key in the ignition switch and turn the switch to position II. If the ignition switch is not turned to position II
within 30 seconds of the end of the 5 minute wait, the engine is automatically immobilised again.

The EKA code will not be recognised if there is an interval of 10 seconds or more between key turns or if the key is
held turned for 5 seconds or more during the procedure.

In some system configurations a successful EKA code entry is indicated by the audible warning device pulsing twice
for a period of 50 ms on, 200 ms off. The theft deterrent LED is switched on for 1 second, all doors unlock, the alarm
disarms and the vehicle is remobilised allowing the engine to start.

If an incorrect code is entered, an audible warning is emitted and the procedure must be repeated. Up to a maximum
of 10 attempts to enter the code is possible. After 10 attempts, the BCU will not allow any further codes to be entered
for a period of 10 minutes.

Single point entry
Single point entry (SPE) allows the driver to unlock the driver's door while leaving all other doors locked.

There are two configurations for single point entry:

SPE not active.

SPE active.

To use SPE, press the unlock button on the handset once. Depressing the unlock button a second time in the space
of one minute unlocks the remaining doors. SPE is also possible by turning the key in the driver's door lock to the
unlock position once. Turning the key to the unlock position again within one minute unlocks the remaining doors.

In order for SPE to operate, the following conditions must be met:

The ignition is off.

All doors are locked.

ALARM SYSTEM AND HORN

86-4-22 DESCRIPTION AND OPERATION

Speed related locking
For added protection the vehicle doors can automatically lock when the vehicle exceeds a specific road speed.

There are two configurations for speed related locking:

Speed related locking not active.

Speed related locking active.

Speed related locking causes the doors to automatically lock when the vehicle exceeds a speed of 4 mph (7 km/h).
When the ignition is switched off, the doors are automatically unlocked. Depressing the instrument panel mounted
central door unlocking switch disables the speed related locking for the duration of the journey.

Speed related locking only activates once per ignition cycle. If speed related locking activates and a door is then
unlocked, the door does not automatically re-lock.

In order for speed related locking to activate the following conditions must be met:

All doors unlocked.

Engine running.

Vehicle speed greater than 4 mph (7 km/h).

Acclimatisation related locking
Acclimatisation related locking allows the engine to be started and then the vehicle locked with a spare key and left
unattended to allow the vehicle interior to reach the desired temperature.

There are two configurations for acclimatisation related locking:

Acclimatisation related locking not active.

Acclimatisation related locking active.

Once the engine is started, the vehicle is locked with a spare key at the driver's door while the engine is running.
During these conditions the alarm is not armed.

In order to activate acclimatisation related locking the following conditions must be met:

Engine running.

All doors closed.

Visual warnings
The direction indicators serve as a visual indication when the alarm is triggered. The direction indicators are also used
as a visual indication during lock/unlock procedures.

There are three configurations of alarm armed/disarmed indication:

No direction indicators on, alarm armed/disarmed/trigger.

Direction indicators on, alarm trigger only.

Direction indicators on, alarm armed/disarmed/trigger.

Dependent on system configuration the direction indicators flash one short pulse to confirm that the alarm is armed
and flash two short pulses to confirm that the vehicle is super locked. If the alarm is triggered the direction indicators
operate in phase with the audible warning. When the alarm is disarmed, the direction indicators flash one long pulse.

Audible warning
An audible warning device is used to indicate that the alarm has been triggered, or a mislock has occurred, or an EKA
request has occurred, or the EKA code has been entered.

There are six audible warning configurations:

No sound (audible warnings disabled).

Alarm sounder only.

Vehicle horn only.

Alarm sounder and vehicle horn.

BBUS only.

Alarm sounder, vehicle horn and BBUS.

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