1999 LAND ROVER DISCOVERY run flat

LIFTING AND TOWING
08-2
Before commencing work on underside of vehicle re-
check security of vehicle on stands.
WARNING: Always chock the wheels when
jacking. The hand brake acts on the the
transmission, not the rear wheels, and may be
ineffective when the wheels are off the ground.
Reverse procedure when removing vehicle from
stands.
Hydraulic ramps
Use only a 'drive on' type ramp which supports a
vehicle by it's own road wheels. If a 'wheel free'
condition is required, use a 'drive on' ramp
incorporating a 'wheel free' system that supports
under axle casings. Alternatively, place vehicle on a
firm, flat floor and support on axle stands.
TOWING
Towing
The vehicle has permanent four wheel drive. The
following towing instructions must be adhered
to:
Towing on 4 wheels with driver
Turn ignition key to position '1' to release steering
lock.
Select neutral in main gearbox and transfer gearbox.
Secure tow rope, chain or cable to towing eye.
Release the handbrake.
The brake servo and power assisted steering
system will not be functional without the engine
running. Greater pedal pressure will be required
to apply the brakes, the steering system will
require greater effort to turn the front road
wheels. The vehicle tow connection should be
used only in normal road conditions, 'snatch'
recovery should be avoided.
Suspended tow
To prevent vehicle damage, front or rear
propeller shaft MUST BE removed, dependent
upon which axle is being trailed.
Mark propeller shaft drive flanges at transfer box and
axles with identification lines to enable the propeller
shaft to be refitted in its original position.

MAINTENANCE
PROCEDURES 10-31
Road/roller test
WARNING: Roller test must be restricted to 3
mph (5 km/h). If 2 wheel rolling road is to be used,
disconnect propeller shaft from the transfer box
output shaft driving the axle which is NOT on the
rolling road.
Testing
1. 2 wheel rolling road: Engage differential lock
using a 10 mm open ended spanner on flats
machined on differential lock selector
shaft.Switch on ignition and check that the
differential lock, electronic brake
distribution and hill descent warning lamps
are illuminated.
2.Check for correct operation of starter switch,
ensure engine starts correctly; leave the engine
running.
3.Check for correct operation of starter switch,
ensure engine starts correctly; leave the engine
running.
4.With vehicle stationary, turn steering from lock
to lock. Check for smooth operation and ensure
there is no undue noise from power steering
pump or drive belt.
5.Depress clutch and select all gears in turn,
check for smooth, notch free engagement.6. Check all vehicle systems for correct
operation.
7.Check for unusual engine, gearbox and
suspension noises.
8.Check braking system operation.
9.Check for smooth gear engagement.
10.Check engine performance.
11.Check operation of all instruments and warning
devices where practicable.
12.Where possible, check for correct operation of
hill descent control (HDC) mechanism. This
should not be carried out if excessive journey
time is required.
13.After road/roller test, carry out a final inspection
of vehicle, with vehicle on a ramp.
14.Check all fluid levels and top-up if necessary.
15. 2 wheel rolling road: Ensure differential lock is
disengaged and propeller shaft is connected on
completion of test. Switch on ignition and
check that differential lock, electronic brake
distribution and hill descent warning lamps
are extinguished.

REAR SUSPENSION
64-22 DESCRIPTION AND OPERATION
Off-road mode (ORM)
ORM is used to raise the rear of the vehicle from normal ride height to the ORM ride height of 100 mm between the
tip of the bump stop and the axle.
ORM is activated by depressing the ORM switch located on the fascia for not less than 0.5 seconds. With the engine
running, all doors closed and the vehicle speed below 18 mph (30 km/h), the audible warning will sound once and the
ORM warning lamp in the instrument pack will start to flash when the switch is released. The compressor will be
started and the air control valves will be energised by the ECU to inflate the air springs and raise the rear of the vehicle.
When the full ORM height is reached, the ECU will terminate compressor operation and close the air valves. The ORM
warning lamp will stop flashing and remain continuously illuminated to inform the driver that the SLS system is in ORM.
When ORM is no longer required, depressing the ORM switch for not less than 0.5 seconds with all doors closed will
lower the SLS to normal ride height. The audible warning will sound once and the ORM warning lamp will flash as the
suspension lowers. The ECU energises the air control valves and the exhaust valve to release air pressure from the
air springs. When standard ride height is reached the ORM warning lamp will extinguish and the ECU will de-energise
the air control valves and the exhaust valve solenoids.
If the SLS is in ORM and the vehicle speed exceeds 18 mph (30 km/h), the ECU will lower the SLS to standard ride
height. The driver will be informed of this by an audible warning and the ORM warning lamp flashing as the suspension
lowers. When normal ride height is achieved, the ORM warning lamp will extinguish.
At sea level, the time to change the SLS from normal ride height to ORM or visa versa will take between 15 and 20
seconds.
If the ECU determines that conditions are not correct for SLS operation, i.e.; axle articulation or system fault, the
audible warning will sound three times to inform the driver that the ORM request has not been granted.
Extended mode
The extended mode is automatically operated by the ECU and requires no input from the driver. Extended mode
operates when the chassis is grounded causing the rear wheels to spin. This information is generated by the ABS
function of the SLABS ECU.
When the ECU senses that the chassis is grounded and the vehicle speed is less than 6 mph (10 km/h), the ECU will
operate the compressor and energise the air control valves for 25 seconds to raise the rear of the vehicle. This
operates irrespective of the mode that the SLS system is in at that time. To inform the driver, the ORM warning lamp
will flash continuously at all times that the system is in extended mode.
The driver can exit the extended mode by depressing the ORM switch for not less than 0.5 seconds or by exceeding
8 mph (13 km/h).
Remote handset SLS control
The remote handset is an accessory item which allows the SLS to be operated between normal ride height and bump
stop height to allow easier connection and disconnection of trailers. The remote handset is similar in appearance to
that of the remote door locking handset but does not have an integral key. A circular button with an arrow is used to
raise the SLS and an oval button with the 'Land Rover' logo is used to lower the SLS.
The remote handset control requires all doors to be closed and the ignition to be in position II, but the engine does
not need to be running.
Pressing the lower button will signal the SLABS ECU, via the RF receiver and the BCU, to energise the exhaust valve
and air control valves. The SLS will lower up to 60 mm (2.36 in) below normal ride height if the button is held. If the
button is released the SLS will stop at that point.
Pressing the raise button will signal the SLABS ECU, via the RF receiver and the BCU, to start the compressor and
energise the exhaust valve and air control valves. The SLS will raise to normal ride height if the button is held. If the
button is released the SLS will stop at that point.
When raising or lowering the SLS using the remote handset, the SLS warning lamp will flash and the audible warning
will sound when the system is operating. When the SLS is fully lowered the warning lamp will stay illuminated. The
SLS will reset to normal ride height if the vehicle speed exceeds 3 mph (5 km/h) for 10 seconds when the SLS is
lowered.

BODY CONTROL UNIT
DESCRIPTION AND OPERATION 86-3-15
Electric seats
The BCU controls the logical operation of the electrically operated front seats. Two modes of operation are available:

+ SEATS, DESCRIPTION AND OPERATION, Description - electric seats.
lElectric seat adjustment is enabled if the ignition is on or the driver's door is opened for a short time period.
lElectric seat adjustment is enabled if the ignition is on and the driver's door is closed.
The seats are operated by four electric motors which control the seat cushion rear up/ down, the seat cushion front
up/ down, seat cushion forward/ rearward and seat squab recline. The electrically powered lumbar adjustment in each
seat is operated by a single motorised air pump and a solenoid located on the seat squab frame. The air pump inflates
a cushion in the seat squab and the solenoid operates a valve to deflate the cushion. The seat squab and cushion
may also contain heater elements to provide heated seat operation.
The switches for electrically operated seats are located either side of the centre console.
Direction indicators and hazard warning lamps
The direction indicator lamps are operated from a three position direction indicator switch on the left hand, steering
column stalk. The BCU only allows the lamps to work as direction indicators when the ignition switch is in position II.
The BCU also controls the lamps to operate as hazard warning lamps and as a visual warning for the anti-theft system,
in which cases all lamps flash simultaneously irrespective of the ignition switch position.
System control of the direction indicators and hazard warning lamps is provided by the BCU operating with the IDM
and two electronic relays located in the passenger compartment fuse box. The IDM and relays are integral parts of
the passenger compartment fuse box and cannot be serviced individually. The serial data bus is used for
communication of status and operation requests between the BCU, IDM and instrument pack.
The hazard warning lamps are operated from a latching pushbutton switch located on the fascia.
All direction indicator/ hazard warning lamp bulbs are rated at 5 Watts.
Headlamps
The BCU contains a feature which allow the vehicle headlamps to be turned on when the remote transmitter is
pressed (courtesy headlamps).
For markets with daylight running lamps, the BCU controls the logical operation of the daylight running lamps. Options
are daylight running lamps are on if the main beam headlamps are off, or the daylight running lamps are on with main
and dipped beam off and the gearbox not in Park.
Front fog lamps
For markets with front fog lamps fitted, the BCU controls the operation of the front fog lamps. Options can be selected
so that the fog lamps will operate with or without the headlamps on main beam.
Instrument pack
The BCU communicates with the instrument pack via a serial data bus.

+ INSTRUMENTS, DESCRIPTION AND OPERATION, Description.
lThe instrument pack provides the BCU and IDM with details of vehicle speed.
lSignals are provided from the IDM to the instrument pack and BCU when the direction indicator lamps are active.
lFor certain markets, the BCU provides a signal to the instrument pack for indicating when the transfer box is in
neutral.
lThe IDM can signal the instrument pack to illuminate a trailer warning lamp. This operates when the IDM senses
that the current drawn by the indicator circuit exceeds a preset threshold.
lThe odometer reading displayed on the instrument pack LCD screen is also stored in non volatile memory in the
BCU. Whenever the ignition is turned from position I to position II, the instrument pack and the BCU compare
their stored values.
lThe gear selector position is displayed on the instrument pack LCD screen under the direction of the BCU.
Starting
The starting system comprises a starter motor and solenoid located at the rear right hand side of the engine. A starter
relay controlled by the BCU is used to supply battery power for starter solenoid operation. The starter motor receives
its feed directly from the battery.