ECU LAND ROVER DEFENDER 1996 Workshop Manual

86ELECTRICAL
6
DESCRIPTION AND OPERATION REV: 05/99 ENGINE IMMOBILISATION
Engine immobilisation is an important aspect of the
vehicle's security system, and occurs automatically
whenever the alarm system is armed.
The system also includes a feature known as 'passive
immobilisation', which is designed to safeguard the
vehicle from theft should the driver forget to arm the
alarm.
Passive immobilisation occurs automatically as
follows:
·Thirty seconds after the starter switch has been
turned off and the driver's door opened.
·Five minutes after the starter switch is turned off or
the alarm system is disarmed.
If the engine has immobilised passively,
re-mobilisation will occur when the starter switch is
turned to position 'II', provided the handset is on the
same ring as key and in close proximity to the switch.
ALWAYS keep the handset on the same ring as the
key.
NEVER attach both handsets to the same key ring.
Any attempt to start the engine while it is immobilised
will cause the engine immobilisation warning light to
flash.
Engine immobilisation override
If the handset is lost or fails to operate, the engine
immobilisation can be overridden by using the starter
key to enter the four digit emergency access code.
The procedure for entering the code is described after
the following note:
NOTE: If the handset is lost or inoperative,
it is impossible to disarm the alarm. As
soon as the door is opened, the alarm will
sound (continuously for up to three 30 second
periods), and continue while the code is being
entered.
1.With the driver's door closed, insert the key into
the starter switch.
2.Turn the switch to position 'II' the required
number of times to enter first digit of code (if first
digit is 4, turn key to position 'II' and then back to
'0' four times.
3.Open the driver's door (to enter first digit) and
then close the door again.
4.Turn the starter switch to position 'II' and back to
'0' the required number of times to enter
SECOND digit of code.
5.Open the driver's door (to enter second digit)
and then close the door again.
6.Turn the starter switch to position 'II' and back to
'0' the required number of times to enter THIRD
digit of code.
7.Open the driver's door (to enter third digit) and
then close door again.
8.Turn the starter switch to position 'II' and back to
'0' the required number of times to enter
FOURTH digit of code.
9.Finally, open and close the driver's door. If the
code has been entered correctly, the anti-theft
indicator light will extinguish, the engine can be
started and the alarm will disarm.
If an incorrect code has been entered:
If the code is entered incorrectly, the anti-theft
indicator light will continue to illuminate and the
engine will fail to start. Before entering the code again,
turn the starter switch to position 'II', hold in this
position for 5 seconds and then switch off.
After three failed attempts, the security system
invokes a delay period of thirty minutes during which
the system will not accept any further codes.

ELECTRICAL
9
DESCRIPTION AND OPERATION IMMOBILISATION AND ALARM SYSTEM CIRCUIT
DIAGRAM
1.Anti-theft alarm indicator light (LED)
2.Engine immobilisation warning light
3.Alarm system fuse - 15 amp
4.Alarm sounder relay
5.Under bonnet lighting fuse
6.Alarm sounder (without battery back-up)
7.Alarm system fuse - 5 amp (position 20)
8.Electronic control unit (ECU)
9.Bonnet switch
10.Alarm sounder protection fuse - 20 amp
(position 10)
11.Starter switch
12.Under bonnet ignition fuse
13.Driver's door switch
14.Vehicle horn switch
15.Vehicle horn
16.Passive coil
17.Starter switch relay
18.Front passenger door switch
19.Hazard warning light fuse - 15 amp (position 1)
20.Ultrasonic sensor
21.Interior lamp and horn fuse - 20 amp (position 3)
22.Alarm sounder (with battery back-up)
23.LH direction indicator lamps
24.RH direction indicator lamps
25.Interior lamp
26.Immobilisation spider
27.Rear side doors and rear door switches
28.Diagnostic connector
29.Diagnostic fuse - 7.5 amp
30.Starter solenoid
31.Fuel switch-off solenoid (injection pump)
32.Generator
33.AerialKey to cable colours
B-Black
G-Green
K-Pink
LG-Light Green
N-Brown
O-Orange
P-Purple
R-Red
S-Slate
U-Blue
W-White
Y-Yellow
The last letter of a colour code denotes the tracer
colour

ELECTRICAL
11
DESCRIPTION AND OPERATION IMMOBILISATION AND ALARM SYSTEM CIRCUIT
DIAGRAM - WITH DDS
1.Anti-theft alarm indicator light (LED)
2.Engine immobilisation warning light
3.Alarm system fuse - 15 amp
4.Alarm sounder relay
5.Under bonnet lighting fuse
6.Alarm sounder (without battery back-up)
7.Alarm system fuse - 5 amp (position 20)
8.Electronic control unit (ECU)
9.Bonnet switch
10.Alarm sounder protection fuse - 20 amp
(position 10)
11.Starter switch
12.Under bonnet ignition fuse
13.Driver's door switch
14.Vehicle horn switch
15.Vehicle horn
16.Passive coil
17.Starter switch relay
18.Front passenger door switch
19.Hazard warning light fuse - 15 amp (position 1)
20.Ultrasonic sensor
21.Interior lamp and horn fuse - 20 amp (position 3)
22.Alarm sounder (with battery back-up)
23.LH direction indicator lamps
24.RH direction indicator lamps
25.Interior lamp
26.Digital diesel shut-off valve (DDS)
27.Rear side doors and rear door switches
28.Diagnostic connector
29.Diagnostic fuse - 7.5 amp
30.Starter solenoid
31.Fuel shut-off solenoid (injection pump)
32.Generator
33.AerialKey to cable colours
B-Black
G-Green
K-Pink
LG-Light Green
N-Brown
O-Orange
P-Purple
R-Red
S-Slate
U-Blue
W-White
Y-Yellow
The last letter of a colour code denotes the tracer
colour

86ELECTRICAL
2
REPAIR BATTERY
Service repair no - 86.15.01
NOTE: If the vehicle is fitted with a battery
backed-up alarm sounder, disconnecting
the vehicle battery will cause the alarm to
sound unless the following procedure is followed:
1.Remove LH front seat cushion.
2.Release retaining clip and remove battery
access cover.
3.Slacken battery negative lead clamp bolt.
4.Turn starter switch 'on'.
5.Turn starter switch 'off' and remove key.
6.Disconnect battery WITHIN 15 SECONDS.
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 negative lead first. If positive
lead is disconnected with negative lead in place,
accidental contact of a wrench to any grounded
metal part could cause a severe spark, possibly
resulting in personal injury. Upon installation of
battery always connect positive lead first.
1.Remove LH front seat cushion.
2.Release retaining clip and remove battery
access cover.
3.Disconnect both battery leads, negative first.
4.Slacken securing nuts and move battery clamp,
with 'J' bolts aside.
5.Remove battery.
NOTE: Coat battery clamps and terminals
with petroleum jelly before refitting.
Refit
6.Position battery and secure with clamp. Ensure
'J' bolts are hooked correctly under retaining
brackets on base of battery box.
7.Reconnect battery leads, positive lead first.
8.Fit battery access cover.
9.Fit seat cushion.

ELECTRICAL
3
REPAIR ELECTRONIC CONTROL UNIT (ECU)
Service repair no - 86.55.85
Remove
1.Remove LH front seat cushion.
2.Release retaining clip and remove battery
access cover.
3.Slacken battery negative lead clamp bolt.
4.Turn starter switch 'on'.
5.Turn starter switch 'off' and remove key.
6.Disconnect battery negative lead.
NOTE: Operation 6 needs to be carried out
within 15 seconds to avoid activating
battery backed-up alarm sounder, if fitted.
7.Remove steering wheel
See STEERING,
Repair, Steering wheel.
8.Remove 4 screws securing instrument panel to
fascia cowl
See INSTRUMENTS, Repair,
Instrument panel.
9.Pull instrument panel away from fascia cowl and
disconnect speedometer cable, multi-plugs,
alarm LED plug lead, heated rear screen lead,
gearbox oil temperature lead and immobiliser
warning light leads.
10.Remove instrument panel.
11.Remove 2 screws securing ECU to fascia cowl
(LH drive shown). On RH drive vehicles ECU is
positioned lower down, on vertical face of fascia
panel.
12.Release ECU from fascia cowl and disconnect
both multi-plugs.
13.Remove ECU.
NOTE: A new ECU must be initialised
using TestBook.
Refit
14.Position ECU at fascia cowl and reconnect both
multi-plugs.
15.Locate ECU on mounting face of fascia cowl and
secure with 2 screws.
16.Position instrument panel to fascia cowl and
reconnect immobiliser warning light leads,
gearbox oil temperature lead, heated rear screen
lead, alarm LED plug lead, multi-plugs and
speedometer cable.
17.Secure instrument panel to fascia cowl with 4
screws
See INSTRUMENTS, Repair,
Instrument panel.
18.Fit steering wheelSee STEERING, Repair,
Steering wheel.
19.Reconnect battery negative lead.
20.Fit battery access cover.
21.Fit LH seat cushion.

ELECTRICAL
5
REPAIR PASSIVE COIL
Service repair no - 86.77.35
Remove
1.Remove LH front seat cushion.
2.Release retaining clip and remove battery
access cover.
3.Slacken battery negative lead clamp bolt.
4.Turn starter switch 'on'.
5.Turn starter switch 'off' and remove key.
6.Disconnect battery negative lead.
NOTE: Operation 6 needs to be carried out
within 15 seconds to avoid activating
battery backed-up alarm sounder, if fitted.
7.Remove steering wheel
See STEERING,
Repair, Steering wheel.
8.Remove 4 screws securing instrument panel to
fascia cowl
See INSTRUMENTS, Repair,
Instrument panel.
9.Pull instrument panel away from fascia and
disconnect speedometer cable, multi-plugs,
alarm LED plug lead, heated rear screen lead,
gearbox oil temperature lead and immobiliser
warning light leads.
10.Remove instrument panel.
11.Remove 7 screws securing upper and lower
halves of nacelle to steering column mounting
bracket
See STEERING, Repair, Steering
column nacelle.
12.Release multi-switch gaiters from both sides of
nacelle.
13.Remove nacelle upper and lower halves from
steering column; collect blanking grommet from
RH side.
14.Disconnect multi-plug and remove passive coil
from starter switch.
Refit
15.Feed passive coil plug lead into fascia cowl area
and reconnect multi-plug .
16.Fit coil on starter switch.
17.Position nacelle upper and lower halves to
steering column mounting bracket and secure
with 7 screws. Do not fully tighten screws at this
stage
See STEERING, Repair, Steering
column nacelle.
18.Check that passive coil is still fitted correctly on
starter switch.
19.Check fit of nacelle at starter switch and steering
column and fully tighten fixing screws.
20.Fit multi-switch gaiters to both sides of nacelle
and check that blanking grommet is located.
21.Position instrument panel to fascia cowl area
and reconnect immobiliser warning light leads,
gearbox oil temperature lead, heated rear screen
lead, alarm LED plug lead, main harness multi-
plugs and speedometer.
22.Secure instrument panel to fascia cowl with 4
screws
See INSTRUMENTS, Repair,
Instrument panel.
23.Fit steering wheelSee STEERING, Repair,
Steering wheel.
24.Reconnect battery negative lead.
25.Fit battery access cover.
26.Fit LH seat cushion.
27.Test immobilisation and alarm system.

86ELECTRICAL
6
REPAIR IMMOBILISATION SPIDER
Service repair no - 86.77.03
Remove
1.Remove LH front seat cushion.
2.Release retaining clip and remove battery
access cover.
3.Slacken battery lead clamp bolts.
4.Turn starter switch 'on'.
5.Turn starter switch 'off' and remove key.
6.Disconnect battery leads.
NOTE: Operation 6 needs to be carried out
within 15 seconds to avoid activating
battery backed-up alarm sounder, if fitted.
7.Remove battery clamp and 'J' bolts.
8.Remove 4 nuts securing immobilisation spider
housing box to fixing studs on front face of
battery box.
9.Remove grommet securing spider harness to
corner face of battery box.
10.Carefully pull harness into battery box, lift spider
housing box and place on front edge of seat
base.
11.Using a suitable sheet to protect inside of
vehicle, grind heads off 6 monobolts securing lid
to spider box housing.
12.Detach lid from housing and disconnect spider
harness plug.
13.Unscrew two nuts and remove immobilisation
spider from lid studs.
NOTE: If spider box lid and/or sealing
gasket is damaged during operation 11 a
new lid will need to be fitted.
NOTE: A new immobilisation spider must
be initialised using TestBook.
Refit
14.Fit immobilisation spider onto lid studs and
secure with retaining nuts.
15.Reconnect harness plug to spider and ensure it
fully 'clicks' home.
16.Position lid and spider assembly into box
housing so that harness plug is furst away from
harness entry.
17.Secure lid to spider box housing with monobolts.
18.Refit harness grommet into spider box, if
disturbed on removal procedures, and ensure
harness covering is fully inserted through
grommet to make water tight seal.
19.Push excess harnes cable through corner face
of battery box and fit grommet.
20.Fit spider housing box to fixing studs and secure
with four nuts.
21.Fit 'J' bolts and clamp to secure battery,
22.Reconnect battery leads.
23.Fit battery access cover.
24.Fit LH seat cushion.
25.Test immobilisation and alarm system.

ELECTRICAL
7
REPAIR BONNET SWITCH
Service repair no - 86.55.89
Remove
1.Disconnect bonnet switch harness multi-plug.
2.Release harness retaining clip from switch
mounting bracket.
3.Press in retaining clips and remove switch from
mounting bracket.
Refit
4.Insert harness multi-plug and bonnet switch into
mounting bracket. Push switch firmly down to
secure in position.
5.Connect harness multi-plug.
6.Fit harness retaining clip in mounting bracket.ULTRASONIC SENSOR
Service repair no - 86.77.32
Remove
1.Carefully prise ultrasonic sensor from cantrail
trim.
2.Disconnect harness plug and remove sensor.
NOTE: Position of sensor will change
according to vehicle type.
Refit
3.Connect harness plug to sensor.
4.Fit sensor to cantrail trim.

86ELECTRICAL
8
REPAIR ALARM SOUNDER
Service repair no - 86.55.87
Remove
1.Remove LH front seat cushion.
2.Release retaining clip and remove battery
access cover.
3.Slacken battery negative lead clamp bolt.
4.Turn starter switch 'on'.
5.Turn starter switch 'off' and remove key.
6.Disconnect battery negative lead.
NOTE: Operation 6 needs to be carried out
within 15 seconds to avoid activating
battery backed-up alarm sounder, if fitted.
NOTE: If an alarm sounder without battery
back-up is fitted, it is not necessary to
disconnect battery.
7.Remove 2 nuts securing power steering pump
reservoir mounting bracket to front, LH inside
wing.
8.Move steering pump reservoir aside to gain
access to alarm sounder.
9.Disconnect harness multi-plug from rear of alarm
sounder.
10.Unscrew 2 bolts and remove alarm sounder from
inside wing.
Top illustration - alarm sounderwithbattery
back-up.
Lower illustration - alarm sounderwithout
battery back-up.
NOTE: A new battery backed-up alarm
sounder will not operate until charged by
vehicle generator for approximately three
hours.
Refit
11.Secure alarm sounder to inside wing, tightening
bolts to
10 Nm (7 lbf/ft).
12.Reconnect multi-plug to alarm sounder.
13.Secure power steering pump reservoir to inside
wing, tightening nuts to
10 Nm (7 lbf/ft).
14.Reconnect battery negative lead.
15.Fit battery access cover.
16.Fit LH seat cushion.

ELECTRICAL
9
REPAIR ALARM SOUNDER RELAY
Service repair no - 86.77.09
Remove
1.Remove screw and lift off LH door check strap
cover.
2.Remove 3 screws and lower wiper motor cover
from fascia bulkhead, (on RH drive models first
remove grab handle).
3.Slide relay multi-plug from retaining bracket and
remove relay.
Refit
4.Secure multi-plug to mounting bracket and fit
new relay.
5.Position wiper motor cover and secure with 3
screws.
6.On RH drive models fit grab handle.
7.Fit door check strap and secure with screw.ANTI-THEFT ALARM INDICATOR LIGHT
Service repair no - 86.45.61
Remove
1.Remove LH front seat cushion.
2.Release retaing clip and remove battery access
cover.
3.Slacken battery negative lead clamp bolt.
4.Turn starter switch 'on'.
5.Turn starter switch 'off' and remove key.
6.Disconnect battery negative lead.
NOTE: Operation 6 needs to be carried out
within 15 seconds to avoid activating
battery backed-up alarm sounder, if fitted.
NOTE: If an alarm sounder without battery
back-up is fitted, it is not necessary to
disconnect battery.
7.Remove steering wheel
See STEERING,
Repair, Steering wheel.
8.Remove 4 screws securing instrument panel to
fascia cowl.
9.Pull instrument panel away from fascia and
disconnect speedometer cable, if necessary.
10.Disconnect alarm indicator light plug lead.
11.Press in retaining lugs and withdraw indicator
light from fascia panel.