1995 LAND ROVER DISCOVERY oil

ELECTRICAL
7
DESCRIPTION AND OPERATION ANTI-THEFT ALARM DESCRIPTION (96 MODELS)
NOTE: The alarm system provides security
protection under wide ranging
circumstances and is fully programmable
to meet market requirements; consequently some
of the features listed will vary dependent on
vehicle model or territory.
The handset is intended to be the primary source of
control for the alarm system. The key should only be
used in the event of handset failure or if perimetric
arming only is required.
Immobilisation
After a time period the vehicle is automatically
immobilised regardless of whether or not the alarm is
armed.
Mobilisation
The handset provides the normal means of
mobilisation. In the event of handset failure, the key
may be used to enter the emergency key access
code.
Perimetric arming
Provides protection whilst the vehicle is still occupied.
Volumetric arming
If movement within the vehicle is detected the alarm
will be triggered.
NOTE: Perimetric arming always
accompanies volumetric arming.
Built-in test
The alarm system has a built-in test procedure, but if
possible any fault finding should normally be
undertaken using TestBook.
Emergency key access (EKA)
In the event of handset failure the alarm can be
disarmed by entry of the EKA code which is unique to
each vehicle.CONTROL SYSTEM
Electronic control unit (ECU) and relays
The ECU is the alarm system 'brain' and controls all
alarm functions. It responds to inputs received, by
supplying suitable outputs to indicate the status of the
alarm system or activating the relevant warning
devices.
Handset
The handset is the primary source of control for the
alarm system i.e. it locks and unlocks the vehicle,
arms and disarms the alarm.
Door key
The vehicle may be locked using the key (perimetric
arming only).
NOTE: The vehicle MUST be unlocked
using the handset. The key may be used to
unlock the vehicle if the handset fails to
operate, see operation, Emergency key access.
Passive coil
The passive coil is located around the starter switch
and triggers the handset (usually located on the
keyring) if it is within close proximity.
Aerial
The aerial is a floating connection which supplies the
alarm ECU with the signal received from the handset.
Immobilisation unit (spider)
Dependent on model or territory, the system may be
fitted with an immobilisation unit which is discreetly
located and provides an interface between the ECU
and immobilised areas of the vehicle.

86ELECTRICAL
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DESCRIPTION AND OPERATION Radio frequency system
The RF system uses frequencies according to market
and both ECU and handset are colour coded:
Territory ECU/Handset............................... Frequency..................
Europe Blue/Blue.................................. 433.92 MHz.........................
NAS Green/Green....................................... 315.00 MHz....................
Japan Green/Green.................................... 315.00 MHz....................
Gulf Green/Green....................................... 315.00 MHz....................
Rest of World Green/Brown........................ 315.00 MHz...................
NOTE: In service NAS, Japan and Gulf will
have the handset changed to brown.
Passive coil
The passive coil excites a receiving coil in the handset
causing it to automatically transmit a remobilisation
signal to the ECU.
Inertia switch and central door locking
Actuation of the inertia switch will cause the doors to
be unlocked. A time-out period (programmable
between 0-5 minutes) will ensue, during which all CDL
and alarm activity is disabled.
NOTE: This feature only applies when the
starter switch is in the on position.
Handset
Under normal circumstances pressing the respective
buttons on the handset once, will unlock or lock the
vehicle. If operating the handset does not achieve the
desired effect
See Repair, Handset.
Functional detail
For full functional details and circuit diagrams
See
Electrical Trouble Shooting Manual..
Vehicle traceability
All Land Rover vehicles are fitted with a multitude of
discreet security features to prevent theft or assist
recovery in the event of a vehicle being stolen. All
vehicles are traceable, since it is impossible to
remove all security identification.

86ELECTRICAL
2
FAULT DIAGNOSIS LUCAS CONSTANT ENERGY IGNITION SYSTEM -
V8i
Preliminary checks
Inspect battery cables and connections to ensure they
are clean and tight. Check electrical condition of
battery.
Inspect all L.T. connections, ensure they are clean
and tight. Check H.T. leads are correctly positioned
and not shorting to ground against any engine
components. Wiring harness and individual cables
should be firmly fastened to prevent chaffing.
Pick-up air gap
Check air gap between pick-up limb and reluctor teeth
is 0.20 - 0.35 mm, using a non-ferrous gauge.
NOTE: Air gap is set initially at factory and
will only require adjusting if tampered with
or when pick-up module is replaced.
TEST 1:
H.T. Sparking
Remove coil/distributor H.T. lead from distributor
cover and hold approximately 6mm from engine block,
using suitable insulated pliers. Switch ignition 'On' and
operate starter.
Regular sparking indicates fault in H.T. distribution,
plugs, timing or fuelling, proceed to Test 6. If no spark
or weak spark occurs proceed to Test 2.TEST 2:
L.T. Voltage
Switch ignition 'On' - engine stationary.
(a) Connect voltmeter to points in circuit indicated
by V1 to V4 and make a note of voltage
readings.
(b) Compare voltages obtained with specified
values listed below:
Expected readings
V1 More than 12 volts.
V2 1 volt maximum below volts at V1.
V3 1 volt maximum below volts at V1.
V4 0 volt - 0.1 volt.
(c) If all readings are correct proceed to Test 3.
(d) Check incorrect reading(s) with chart to identify
area of possible faults, i.e. faults listed under
heading SUSPECT and rectify.
(e) If coil and amplifier is suspected, disconnect L.T.
lead at coil, repeat V3. If voltage is still incorrect,
fit new coil. If voltage is now correct, check L.T.
lead, if satisfactory fit new amplifier.
(f) If engine will not start proceed to Test 3.

ELECTRICAL
3
FAULT DIAGNOSIS 1 2 3 4 SUSPECT
L * * * DISCHARGED BATTERY
* L L * IGN. SWITCH AND/OR
WIRING
* * L * COIL OR AMPLIFIER
* * * H AMPLIFIER GROUND
Key
*Expected Voltage
HVoltage higher than expected
LVoltage lower than expectedTEST 3:
Amplifier Switching
Connect voltmeter between battery positive (+ve)
terminal and H.T. coil negative (-ve) terminal.
Voltmeter should register 0 volts.
Switch ignition 'On', voltmeter should still register 0
volts.
Crank engine, voltmeter reading should increase
when cranking, in which case proceed to Test 5.
If no increase in voltage during cranking proceed to
Test 4.

86ELECTRICAL
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FAULT DIAGNOSIS TEST 4:
Pick-up Coil Resistance
Remove amplifier.
Connect ohmmeter leads to two pick-up terminals in
body of distributor.
The ohmmeter should register between 2k and 5k
ohm if pick-up is satisfactory. If ohmmeter reading is
correct, check all connections between pick-up and
amplifier, if satisfactory, fit new amplifier. If engine still
does not start carry out Test 5.
Change pick-up if ohmmeter reading is incorrect. If
engine still does not start proceed to Test 5.TEST 5:
Coil H.T. Sparking
Remove existing coil/distributor H.T. lead and fit test
H.T. lead to coil tower. Using suitable insulated pliers,
hold free end about 6mm from engine block and crank
engine. There should be good H.T. sparking.
If weak or no sparking, fit new coil, repeat test.
H.T. sparking good, repeat test with original H.T. lead.
If sparking is good carry out Test 6.
If weak or no sparking, fit new H.T. lead, if engine will
not start carry out Test 6.

ELECTRICAL
5
FAULT DIAGNOSIS TEST 6:
Rotor Arm
Remove distributor cover. Disconnect coil H.T. lead
from cover, using insulated pliers hold about 3mm
above rotor arm electrode and crank the engine.
There should be no H.T. sparking between rotor and
H.T. lead. If satisfactory carry out Test 7.
If H.T. sparking occurs, an earth fault on rotor arm is
indicated. Fit new rotor arm. If engine will not start
carry out Test 7.
TEST 7:
Visual and H.T. Cable Checks
Examine: Should be:
1. Distributor Cover Clean, dry, no tracking marks.....................................................
2. Coil Top Clean, dry, no tracking marks....................................................................
3. H.T. Cable Insulation Must not be cracked, chafed or perished...............................................
4. H.T. Cable Continuity Must not be open circuit..............................................
5. Sparking Plugs Clean, dry, and set to correct gap........................................................
NOTE:
1. Reluctor Must not foul pick-up or leads...................................................................
2. Rotor and Insulation Cover Must not be cracked or show signs of tracking marks.....................................

ELECTRICAL
3
REPAIR BATTERY
Service repair no - 86.15.01
NOTE: Some vehicles are fitted with a
battery backed-up sounder. Disconnecting
the vehicle battery will cause the alarm to
sound unless the following procedure is followed:
1.Turn starter switch 'ON' then 'OFF'.
2.Disconnect battery WITHIN 15 SECONDS (see
WARNING).
If alarm is accidentally activated, ensure sounder is
connected and silence by turning the starter switch to
position II.
Remove
WARNING: During battery removal or
before carrying out any repairs or
maintenance to electrical components
always disconnect battery negative lead first. If
positive lead is disconnected with negative lead in
place, accidental contact of wrench to any
grounded metal part could cause a severe spark,
possibly resulting in personal injury. Upon
installation of battery connect positive lead first.
3.Disconnect both battery leads, negative first.
4.Release four nuts securing battery bracket in
position.
5.Remove bracket.
6.Remove battery.
Refit
7.Reverse removal procedure.
NOTE: Coat battery clamps and terminals
with petroleum jelly before refitting.DISTRIBUTOR-LUCAS 35 DLM8 - V8i
Service parts
1. Cap
2. HT brush and spring
3. Rotor arm
4. Insulation cover
5. Pick-up module and base plate assembly
6. Vacuum unit
7. Amplifier module
8. 'O'-ring oil seal
9. Gasket

ELECTRICAL
5
REPAIR ELECTRONIC IGNITION - V8i
A Lucas 35DLM8 distributor is employed. This has a
conventional vacuum advance unit and centrifugal
automatic advance mechanism.
A pick-up module, in conjunction with a rotating timing
reluctor inside distributor body, generates timing
signals. These are applied to an electronic ignition
amplifier module mounted on side of distributor body.
NOTE: Pick-up air gap is factory set. Do
not adjust gap unless pick-up is being
changed or base plate has been moved.
Use a non-ferrous feeler gauge to set air gap.
IGNITION COIL
Service repair no - 86.35.32
Remove
1.Disconnect battery negative lead.
2.Noting their fitted positions, disconnect electrical
leads from ignition coil.
3.Remove two bolts securing ignition coil clamp,
recover suppressor.
4.Remove coil.
Refit
5.Reverse removal procedure.DISTRIBUTOR - V8i
Service repair no - 86.35.20
Remove
1.Disconnect battery negative lead.
2.Disconnect vacuum hose.
3.Remove distributor cap.
4.Disconnect low tension lead from coil.
5.Mark distributor body and centre line of rotor
arm.
6.Add alignment marks to distributor and front
cover.
NOTE: Marking distributor enables
refitting in exact original position, but if
engine is turned while distributor is
removed, complete ignition timing procedure
must be followed.
7.Release distributor clamp and remove
distributor.