engine oil LAND ROVER DISCOVERY 1999 Workshop Manual

BODY CONTROL UNIT
DESCRIPTION AND OPERATION 86-3-25
Rear wipers and washers
The rear wiper is initially operated for a period of 4 seconds when the rear wiper switch is pressed, to complete two
full cycles. After this, the rear wiper will operate every other time the front wiper completes a wipe operation. During
the wipe operation, the front and rear wipers are synchronised, and changes to the delay period during intermittent
wipe will change the delay period for both front and rear wipers.
Operation of the rear washer switch causes the washer motor to operate for as long as the switch is operated. The
wiper also operates while the switch is depressed and for a further 4 seconds after the switch is released.
The BCU checks for the following inputs to determine when to provide the rear wiper enable signal:
lIgnition state.
lRear wiper switch.
lFront intermittent wiper rate.
lFront intermittent wiper switch.
If the ignition switch is in the off or crank position, the rear wipers are not active and the rear wiper enable output is
switched off.
In the event of a communications link failure occurring while the rear intermittent wipe programme is in operation, the
rear wiper enable output is switched off.
Reverse gear wipe
The BCU changes the operation of the rear wiper when the front wiper is active and reverse gear is selected. The rear
wiper operation rate used when the preconditions have been satisfied depend on the prevailing front wiper operating
mode and the position of the rear wiper switch. If the rear wiper is on or the front wiper is operating at an intermittent
rate when reverse gear is selected, the BCU will operate the rear wiper continuously for 4 seconds via the IDM. After
the initial period, the rear wiper will operate at the same rate as the front wiper.
The BCU checks for the following inputs to determine when to provide the rear wiper enable signal if the vehicle is in
reverse gear:
lIgnition state.
lRear wiper switch.
lFront intermittent wiper rate.
lReverse gear selected.
lFront intermittent wiper switch.
lFront wiper switch state.
lFront wash/ wipe in progress flag.
In the event of a communications link failure occurring while the reversing wipe is in operation, the rear wiper enable
output is switched off.
Headlamp wash
The headlamp wash will only operate when the headlamps are on, and then only every third time the front windscreen
wash button is pressed. When the BCU operates the headlamp washers, it activates the washer pump relay for a
period of 500 ms. The BCU supplies an earth path for the coil of the power wash relay located in the engine
compartment fuse box when the washer function is selected.
The BCU checks for the following inputs to determine when to provide power to the headlamp power wash relay:
lIgnition state.
lFront washer pump switch.
lDipped beam.
lMain beam state.
If the ignition switch is in the off position, the headlamp power wash relay is also held off. if the ignition state is crank,
the headlamp power wash relay is switched off and the headlamp power wash counter is reset to 0.
In the event of a communications link failure occurring while the headlamp power wash relay in on , the relay remains
on until the 500 ms timer has completed, then the relay is switched off.

BODY CONTROL UNIT
86-3-28 DESCRIPTION AND OPERATION
Courtesy headlamps
This feature activates the headlamps for 30 seconds when the lock button on the remote transmitter is held down for
longer than 1 second. The headlamps will extinguish if the BCU receives either a lock or an unlock signal from the
remote transmitter.
The BCU checks the status of the following inputs to determine the correct qualifying conditions for requesting
courtesy headlamps:
lIgnition state.
lRemote locking request.
lRemote unlocking request.
lLazy locking request.
If the ignition is off and a lazy locking request is received, the courtesy headlamps are switched on and an internal
timer is turned on in the BCU which operates for 30 seconds. If the 30 second timer expires or a request for remote
locking or remote unlocking is received, the courtesy headlamps will be turned off.
When main beam is selected, the IDM also provides a signal to the instrument pack to switch on the main beam
warning lamp. An additional signal 'main beam indicator disable' is used to prevent the daylight running lamps
illuminating the main beam indicator when the main beam is in the daylight running lamp state and the main beam
indicator disable signal is on.
Lights on alarm
The lights on alarm in the instrument pack operates when the driver's door is open and the side lamps or headlamps
are on. The system uses inputs from the driver's door switch and the lighting switch to determine the logical conditions
that need to occur for switching on the alarm. The BCU carries out the logic operation and communicates with the
instrument pack using the serial data bus; the instrument pack will be requested to sound the alarm if the logic inputs
indicate that the driver's door is open with the lights still on.
Supply voltage is provided through the lighting switch to the IDM which acts as the signal line to indicate that the lights
are on for the logic circuits in the IDM and BCU. When the driver's door is opened, a second feed is supplied to the
BCU through the driver's door switch to indicate the condition. In this logic condition (lights on and driver's door open)
the BCU signals the instrument pack to operate the audible warning. If the lights are switched off or the driver's door
is closed the logic condition will be changed and the audible warning will be switched off.
Daylight running lamps
The BCU operates the daylight running lamps (where fitted) via the IDM. The daylight running lamps option can be
programmed in one of three states dependent on market/ customer requirements, these are:
lOption 1– no daylight running lamps.
lOption 2 – on with main beam off.
lOption 3 – on with main and dipped beam off and gearbox not in Park.
The BCU will ensure the logical conditions are satisfied for the lamps to operate under the set conditions. The BCU
checks the status of the following inputs to determine the logic action for providing an output to the daylight running
lamp relay:
lMain beam state.
lEngine running (link from instrument pack).
lDipped beam.
lGearbox state.
A voltage supply is fed to the coil of the daylight running lamp relay and the IDM. When the preconditions are satisfied
for daylight running lamp operation, the BCU sends a signal for the IDM to complete the circuit to earth to switch on
the daylight running lamps. The logical inputs are checked to ensure that the engine is running before switching the
relay to turn on the daylight running lamps. The engine running signal has to be present for at least 2 seconds before
the daylight running lamp relay can be switched on.
Fog lamps
The BCU operates the rear fog lamps and the front fog lamps (where fitted) via the IDM. The BCU front fog lamp
operation can be programmed to operate under one of three set conditions. The BCU will ensure the logical conditions
are satisfied for the lamps to operate under the set conditions.

BODY CONTROL UNIT
DESCRIPTION AND OPERATION 86-3-31
Gear position indicator illumination
On automatic gearbox models, two variations of illumination for the gear position indicators on the selector lever can
be programmed into the BCU. In option 1, illumination is provided when the ignition is on. In option 2, illumination is
enabled when the ignition is on and the side lamps are off.
Starter relay
The BCU checks the status of the following inputs and internal BCU conditions to determine whether or not to provide
an output to enable the starter relay:
lAutostart inhibit (vehicles with automatic gearbox only).
lSecurity start inhibit (immobilisation check).
lEngine running (link to instrument pack).
lEEPROM locked (internal check).
lIDM and BCU matched.
When the BCU receives a crank signal from the ignition switch, an earth path is completed to the starter relay coil,
provided that the security system has been de-activated. If the ECM has not received a valid unlock/ remobilise signal,
the starter relay will be disengaged and the engine stopped. The BCU also receives an engine running signal from
the instrument pack, so that if the ignition key is turned to the crank position while the engine is running, the starter
motor relay will not be engaged.
If the logic conditions are correct to allow starter operation, the completion of the earth path from the starter relay coil
to the BCU energises the coil and the relay contacts close to supply battery power to the starter motor.
When the ignition switch is released from the crank position, the power supply feed from the ignition switch to the
starter relay coil is interrupted and the relay contacts open to prevent further battery feed to the starter motor.
If a communications link failure is experienced, the BCU will be prevented from detecting the 'engine running'
condition and the BCU will default to assume that the engine is not running.
Cruise control
The Neutral/ Reverse/ Park/ Brake selected output is used by the cruise control system. The BCU checks for the
following inputs:
lIgnition on.
lGearbox state.
lBrake switch activated.
For vehicles with manual transmission, Neutral/ Reverse/ Park/ Brake selected output is on if the ignition is on and
brake switch activated is on. Otherwise, the Neutral/ Reverse/ Park/ Brake selected output is off.
For vehicles with automatic transmission, the Neutral/ Reverse/ Park/ Brake selected output is on if the ignition is on
and brake switch activated is on, or if the ignition is on and 'gearbox state' is in Neutral, Park or Reverse. Otherwise
Neutral/ Reverse/ Park/ Brake selected output is off.
Shift interlock (where fitted)
On automatic gearbox models, the BCU and IDM combine to operate a shift interlock solenoid, so that the gear
selector lever can only be moved when certain logical conditions have been satisfied. Operation of the interlock may
be affected, if the battery becomes discharged.

+ AUTOMATIC GEARBOX - ZF4HP22 - 24, DESCRIPTION AND OPERATION, Description.
When the gear selector lever is in the Park position and the ignition is off, an interlock solenoid is de-energised, locking
the gear selector lever in the Park position.
The gear selector lever can only be moved from the Park position when the ignition is switched on and the brake pedal
is depressed. When these conditions are satisfied, the brake pedal switch signal is received by the BCU which then
signals the IDM to energise the interlock relay. When the interlock relay is energised, the interlock solenoid is
operated, unlocking the gear selector lever.
When the brake pedal is released, the feed to the BCU is removed and the shift interlock solenoid is de-energised.
The locking mechanism controlled by the solenoid will lock the gear selector lever once it is returned to the Park
position.

ALARM SYSTEM AND HORN
DESCRIPTION AND OPERATION 86-4-13
Passive remobilisation exciter coil
The passive remobilisation exciter coil consists of a coil around the steering column lock. The coil energises to create
a magnetic field when the ignition is switched to position II.
This coil activates the handset initiating the mobilisation of the vehicle.
Input/Output
The input to the passive remobilisation exciter coil from the BCU is a 12 volts 125 kHz sinewave. The passive
remobilisation exciter coil also receives an ignition controlled power supply via fuse 20 (15 amperes) located in the
engine compartment fuse box. On receiving these signals, a magnetic field is generated which activates the handset
to produce a remobilisation signal. This remobilisation signal is transmitted to the remote receiver and onto the BCU
to allow the engine to start.

ALARM SYSTEM AND HORN
DESCRIPTION AND OPERATION 86-4-21
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:
lpassive immobilisation not active
lpassive 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:
lDriver's door closed.
lFuel cut-off switch not tripped.
lKey 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:
lPassive immobilisation not active.
lPassive immobilisation active.
lEKA 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.
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:
lEKA not active (no immobiliser fitted).
lEKA active.
lEKA with super locking on receiving good passive remobilisation exciter coil signal.

HARNESSES
86-7-8 REPAIRS
Harness - engine - V8
$% 86.70.17
Remove
1.Remove upper inlet manifold.

+ MANIFOLDS AND EXHAUST
SYSTEMS - V8, REPAIRS, Gasket - inlet
manifold - upper - Without Secondary Air
Injection.
2.Disconnect injector multiplugs, release harness
from fuel rail.
3.Disconnect ignition coil multiplugs.4.Release and disconnect both HS
2O sensor
multiplugs.
5.Disconnect CKP sensor multiplug.

HARNESSES
REPAIRS 86-7-11
20.Remove 3 nuts securing RH exhaust front pipe
to manifold. Remove and discard gasket.
21.Remove bolt securing starter heat shield and
remove heat shield.
22.Remove nut securing battery cable to starter
and disconnect solenoid cable.
23.Disconnect both knock sensor multiplugs.24.Remove bolt securing harness clip to LH side of
engine.
25.Disconnect camshaft sensor and oil pressure
switch multiplugs.
26.Remove engine harness.

HARNESSES
86-7-12 REPAIRS
Refit
1.Position engine harness around engine.
2.Connect oil pressure switch and camshaft
sensor multiplugs.
3.Fit and tighten bolt securing harness to LH side
of engine.
4.Connect both knock sensor multiplugs.
5.Connect battery cable and solenoid cable to
starter motor.
6.Position starter heat shield and secure with
bolt.
7.Clean exhaust flange mating faces, using a
new gasket align exhaust fit nuts and tighten to
60 Nm (44 lbf.ft).
8.Remove stand(s) and lower vehicle.
9.Position harness into footwell and secure
grommet.
10.Connect ECM multiplugs.
11.Position toe board and secure with trim fixings.
12.Connect engine harness to main harness
multiplug and secure earth lead.
13.Connect EVAP solenoid multiplug.
14.Connect both fuse box multiplugs.
15.Position starter lead to fuse box and secure
screw.
16.Fit fuse box cover.
17.Position battery positive lead to battery and
secure nut.
18.Secure harness to coolant rail.
19.Position alternator cables and tighten terminal
B+ to 18 Nm (13 lbf.ft) and terminal D+ to 5 Nm
(3.7 lbf.ft)
20.Connect coolant temperature sensor multiplug.
21.Connect A/C compressor multiplug.
22.Secure harness clip to rear of LH cylinder head.
23.Connect CKP sensor multiplug.
24.Secure injector harness and connect injector
multiplugs.
25.Connect coil multiplugs.
26.Connect and secure HS
2O sensor multiplug
27.Fit upper inlet manifold.

+ MANIFOLDS AND EXHAUST
SYSTEMS - V8, REPAIRS, Gasket - inlet
manifold - upper - Without Secondary Air
Injection.
28.Connect battery earth lead.
Harness - engine - diesel
$% 86.70.17
Remove
1.Remove engine acoustic cover.
2.Remove battery carrier.

+ CHARGING AND STARTING,
REPAIRS, Battery carrier.
3.Remove engine compartment fuse box cover.
4.Remove bolts securing battery and alternator
leads to fuse box.
5.Remove bolt securing heater plug lead to fuse
box.
6.Disconnect 2 engine harness multiplugs from
fuse box.

HARNESSES
REPAIRS 86-7-13
7.Disconnect 2 engine harness multiplugs from
ECM and main harness.
8.Disconnect multiplug from EGR solenoid.
9.Disconnect multiplug from oil pressure switch. 10.Remove nut and disconnect battery lead from
starter solenoid.
11.Disconnect Lucar from starter solenoid.
12.Disconnect multiplug from CKP sensor.

HARNESSES
REPAIRS 86-7-15
21.Disconnect multiplugs from A/C compressor,
turbocharger solenoid valve, AAP sensor and
MAF sensor.
22.Release harness clips from coolant hose and
PAS hose.
23.Note the route of the engine harness, release
from underneath of inlet manifold and remove
from engine.
Refit
1.Position harness on engine.
2.Connect multiplugs to A/C compressor,
turbocharger solenoid valve, AAP and MAF
sensors.
3.Position harness clips to coolant and PAS
hoses.
4.Connect multiplug to ECT sensor.
5.Position harness to front of cylinder head and
tighten bolts to 10 Nm (7 lbf.ft).
6.Connect injector multiplug.
7.Connect multiplug and position battery cable to
alternator and tighten nut.
8.Connect multiplug to fuel temperature sensor.
9.Connect multiplug to MAP sensor.
10.Connect glow plugs.
11.Connect CKP sensor multiplug.
12.Connect Lucar to starter solenoid.
13.Connect battery lead to starter solenoid and
tighten nut to 10 Nm (7 lbf.ft).
14.Position harness clip to coolant pipe.
15.Locate harness over bell housing and connect
multiplug to oil pressure switch.
16.Connect 2 multiplugs to EGR solenoids.
17.Connect engine harness multiplug to ECM and
main harness.
18.Connect engine harness multiplugs to fuse
box.
19.Position glow plug lead to fuse box and tighten
bolt to 3.5 Nm (2.6 lbf.ft).
20.Position battery and alternator leads to fuse
box and tighten bolts to 6 Nm (4.4 lbf.ft).
21.Fit engine compartment fuse box cover.
22.Fit battery carrier.
23.Fit engine acoustic cover.
Harness - main
$% 86.70.07
Remove
1.Remove heater assembly.

+ HEATING AND VENTILATION,
REPAIRS, Heater assembly - models with
air conditioning.

+ HEATING AND VENTILATION,
REPAIRS, Heater assembly - models
without air conditioning.
2.Remove 4 clips securing LH and RH trim
panels to lower 'A' post.
3.Remove both lower 'A' post trim panels.
4.Remove air filter assembly.

+ ENGINE MANAGEMENT SYSTEM -
V8, REPAIRS, Air cleaner assembly.
5.Remove battery tray.
6.Remove front bumper.

+ EXTERIOR FITTINGS, REPAIRS,
Bumper assembly - front.