1999 LAND ROVER DEFENDER turn signal

26COOLING SYSTEM
6
DESCRIPTION AND OPERATION By-pass flow valve
The by-pass flow valve is held closed by a light spring. It operates to further aid heater warm-up. When the main
valve is closed and the engine speed is below 1500 rev/min, the coolant pump does not produce sufficient flow
and pressure to open the valve. In this condition the valve prevents coolant circulating through the by-pass circuit
and forces the coolant through the heater matrix only. This provides a higher flow of warm coolant through the
heater matrix to improve passenger comfort in cold conditions.
When the engine speed increases above 1500 rev/min the coolant pump produces a greater flow and pressure
than the heater circuit can take. The pressure acts on the flow valve and overcomes the valve spring pressure,
opening the valve and limiting the pressure in the heater circuit. The valve modulates to provide maximum coolant
flow through the heater matrix and yet allowing excess coolant to flow into the by-pass circuit to provide the
engines cooling needs at higher engine rev/min.
Outlet Housing
A cast aluminium outlet housing is attached to the cylinder head with three bolts and sealed with a gasket. Coolant
leaves the engine through the outlet housing and is directed through a hose to the heater matrix, the radiator or
the by-pass circuit.
An Engine Coolant Temperature (ECT) sensor is installed in a threaded port on the side of the outlet housing. The
sensor monitors coolant temperature emerging from the engine and sends signals to the Engine Control Module
(ECM) for engine management and temperature gauge operation.
Expansion Tank
The expansion tank is located in the engine compartment. The tank is made from moulded plastic and attached to
brackets on the right hand inner wing. A maximum coolant when cold level is moulded onto the tank.
Excess coolant created by heat expansion is returned to the expansion tank from the radiator bleed pipe at the top
of the radiator. An outlet pipe is connected into the coolant pump feed hose and replaces the coolant displaced by
heat expansion into the system when the engine is cool.
The expansion tank is fitted with a sealed pressure cap. The cap contains a pressure relief valve which opens to
allow excessive pressure and coolant to vent through the overflow pipe. The relief valve is open at a pressure of
1.4 bar (20 lbf.in) and above.
Heater Matrix
The heater matrix is fitted in the heater assembly inside the passenger compartment. Two pipes pass through the
bulkhead into the engine compartment and provide coolant flow to and from the matrix. The pipes from the
bulkhead are connected to the matrix, sealed with’O’rings and clamped with circular rings.
The matrix is constructed from aluminium with two end tanks interconnected with tubes. Aluminium fins are
located between the tubes and conduct heat from the hot coolant flowing through the tubes. Air from the heater
assembly is warmed as it passes through the matrix fins. The warm air is then distributed in to the passenger
compartment as required.
When the engine is running, coolant from the engine is constantly circulated through the heater matrix.
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ELECTRICAL
3
DESCRIPTION AND OPERATION ANTI-THEFT ALARM - FROM 02MY
The alarm and immobilisation system on 2002MY Defender is similar to that used on Discovery Series I (LJ)
models from 1996MY. The alarm system comprises the anti-theft alarm ECU, bonnet and door switches and a
volumetric sensor.
Anti-Theft Alarm ECU
The anti-theft alarm ECU is located behind the instrument pack and receives a permanent battery supply via fuses
6 and 7 in the under seat fuse box. The ECU also receives a battery supply via the ignition switch position II and
fuse 1 in the passenger compartment fuse box. The ECU is connected to the various supporting components by
two harness connectors.
The ECU controls the alarm system (perimetric and volumetric security), CDL system, engine immobilisation
system (Td5 only) and various other vehicle functions including direction indicators and interior lamps.
The anti-theft alarm ECU incorporates an RF receiver and antenna for reception of RF signals from the remote
handset for locking and alarm arming. The antenna is unterminated at one end, and for optimum performance the
antenna must not be wound around adjoining harnesses.
The anti-theft alarm ECU operates at one of two frequencies which are identified by a label on the unit. The
frequencies are:
433 MHz - Europe, Gulf States, South Africa
315 MHz - North America, South East Asia, Japan, Australia.
The anti-theft alarm ECU also incorporates an integral inertia switch. In the event of an impact of sufficient severity
to trigger the inertia switch when the ignition is on, the ECU will unlock all doors and operate the hazard warning
lamps. The ECU will remain in this condition for a pre-programmed period of 2 minutes. To reinstate CDL
functionality and to deactivate the hazard warning lamps, the ignition should be turned off and then on after the 2
minute timer has expired.
NOTE: There is a separate inertia switch for fuel cut off.
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86ELECTRICAL
6
DESCRIPTION AND OPERATION Volumetric Sensor
The volumetric sensor is located behind the RH’B’post on 90/110 station wagon models, on the headlining
between the interior lamp and rear view mirror on 90/110 pick-up models and on the headlining above the RH
door on 130 crewcab models.
The volumetric sensor operates by emitting a signal, which is received back to the sensor as it bounces back from
objects inside the vehicle. Once armed, the sensor will detect a disturbance to the returned waves. This is sensed
by the anti-theft alarm ECU which activates the alarm sounder or BBUS.
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ELECTRICAL
13
DESCRIPTION AND OPERATION Passive Immobilisation
Passive immobilisation occurs when the key is removed from the ignition switch and the drivers door is opened,
after a period of 30 seconds the engine will become immobilised. If the ignition is turned off or the key is removed
from the ignition switch and drivers door is not opened, the engine will become immobilised after 5 minutes.
The passive immobilisation system operates in conjunction with the transponder coil located around the ignition
switch barrel. The transponder coil emits an electro magnetic waveform signal which excites the remote handset
into transmitting a remobilisation signal. When remobilisation is requested, the anti-theft alarm ECU transmits an
appropriate code to the ECM on Td5 models or the engine immobilisation ECU on 300Tdi models.
Active immobilisation
Active immobilisation is only invoked when the vehicle is locked using the remote handset. Active immobilisation
performs the same engine disable functionality as the passive immobilisation previously described, but includes
full CDL and activation of perimetric and volumetric alarm modes.
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86ELECTRICAL
14
DESCRIPTION AND OPERATION Emergency Key Access (EKA)
If the vehicle is in an immobilised condition and the remote handset is not available or inoperable, an EKA
procedure using the vehicle key is available to remobilise the engine systems. The EKA code is supplied with the
vehicle and is shown on the security card supplied with the owners handbook.
NOTE: This feature is only available in markets where full alarm functionality is specified.
The EKA code involves the input of a unique four digit code which is entered using the ignition switch and the
drivers door switch. Note that the alarm sounder will operate as soon as the drivers door is opened and will
continue until the sequence is successfully completed.
To enter the code (2, 3, 4, 5 for example) perform the following steps:
1.Remove the handset from the key ring and position the handset well away from the ignition switch when
entering the code.
2.Open the driver’s door and immediately insert the key in the ignition switch and turn the ignition switch to
position II. Hold this position until the alarm sounds, then switch the ignition off (position 0) and close the
driver’s door.
3.Enter the first digit of the code. Turn the ignition on (to position II) and then off twice. Open and close the
driver’s door to enter the first digit.
4.Enter the second digit. Turn the ignition on and then off, three times. Open and close the driver’s door to
enter the second digit.
5.Enter the third digit. Turn the ignition on and then off, four times. Open and close the driver’s door to enter
the third digit.
6.Enter the fourth digit. Turn the ignition on and then off, five times. Open and close the driver’s door to enter
the fourth digit. If the code has been entered correctly, the alarm LED in the instrument pack will extinguish
and the engine can be started after the last closure of the driver’s door.
If a digit is incorrectly entered, holding the ignition switch in the on position for more than 5 seconds will reset the
sequence. The code must then be re-entered from the beginning.
If the EKA code is correctly entered, the security LED will illuminate for 1 second, the immobilisation will be
disabled and the alarm sounder will cease to operate.
If the EKA code is incorrectly entered, the alarm sounder will sound twice and the correct code must be
re-entered, If the EKA code is incorrectly entered three times the system invokes a 30 minute lockout. This is
signalled by the LED flashing with a long illuminated period followed by a short extinguished period for the lockout
duration.
NOTE: Disabling the alarm and immobilisation system using the EKA procedure is only valid for
one ignition on/off cycle. When the ignition is switched off, the immobilisation system will be
activated after a period of 30 seconds. If the remote handset is still unavailable, the EKA
procedure will have to be repeated each time the vehicle is to be driven.
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