1999 LAND ROVER DISCOVERY bulb

AUTOMATIC GEARBOX - ZF4HP22 - 24
DESCRIPTION AND OPERATION 44-17
Operation
Refer to illustration.

+ AUTOMATIC GEARBOX - ZF4HP22 - 24, DESCRIPTION AND OPERATION, Control schematic.
When the ignition is switched on, a bulb check is performed on the transmission temperature warning lamp and the
mode warning lamps by the instrument pack and the EAT ECU respectively. The warning lamps are illuminated for
approximately 3 seconds and then extinguished.
The gear position switch outputs are monitored by the BCU and the EAT ECU. The BCU outputs gear position signals
to illuminate the position indicators each side of the gear selector lever and on the odometer LCD in the instrument
pack.
In D, 3, 2, and 1, the EAT ECU outputs control signals to the gearbox to select the required gear.
In D, all forward gears are available for selection by the EAT ECU. In 3, 2 and 1, a corresponding limit is imposed on
the highest gear available for selection. When R is selected, reverse gear only engages if the vehicle is stationary or
moving at 5 mph (8 km/h) or less. When R is deselected, reverse gear only disengages if the vehicle is moving at 4
mph (6 km/h) or less.
Selector lever interlock (where fitted)
The interlock solenoid on the selector lever is de-energised unless the foot brake is applied while the ignition is on.
While de-energised, the interlock solenoid allows the selector lever to move through the range unless P is selected.
On entering the P position, the interlock solenoid engages a latch which locks the selector lever. When the ignition is
on and the foot brake is applied, the BCU energises the interlock solenoid, which disengages the latch and allows the
selector lever to be moved out of P.
Economy, sport and manual modes
During the power-up procedure after the ignition is switched on, the EAT ECU defaults to an economy mode. Pressing
the mode switch causes the EAT ECU to change between the economy mode and the sport or the manual mode,
depending on the range selected on the transfer box:
lIf the transfer box is in high range, the EAT ECU changes to the sport mode and illuminates the sport mode
warning lamp in the instrument pack. In the sport mode the gearbox is more responsive to accelerator pedal
movement. Downshifts occur earlier and upshifts occur later.
lIf the transfer box is in low range, the EAT ECU changes to the manual mode and illuminates the manual mode
warning lamp in the instrument pack. Kickdown is disabled and the EAT ECU maintains the gearbox in the gear
selected on the selector lever (D = 4th gear) to give improved off road performance. Downshifts occur only to
prevent the engine stalling. From a standing start, the vehicle pulls away in 1st gear and, if a higher gear is
selected, upshifts almost immediately to the selected gear (shifts of more than one gear can occur).
After a second press of the mode switch the EAT ECU reverts to the economy mode, for the range selected on the
transfer box, and extinguishes the related mode warning lamp in the instrument pack.
Shift control
To provide the different driving characteristics for each mode of operation, the EAT ECU incorporates different shift
maps of throttle position/engine speed. Base shift points are derived from the appropriate shift map. When a shift is
required, the EAT ECU sends a request to the ECM for a reduction in engine torque, in order to produce a smoother
shift. The percentage of torque reduction requested varies according to the operating conditions at the time of the
request. When the EAT ECU receives confirmation of the torque reduction from the ECM, it then signals the shift
solenoid valves in the gearbox to produce the shift. To further improve shift quality, the EAT ECU also signals the
pressure regulating solenoid valve to modulate the hydraulic pressure and so control the rate of engagement and
disengagement of the brake clutches.
With time, the components in a gearbox wear and the duration of the gear shifts tends to increase, which has an
adverse effect on the brake clutches. To counteract this, the EAT ECU applies a pressure adaptation to each shift.
To calculate the adaptations, the EAT ECU monitors the pressure modulation used, and time taken, for each shift. If
a subsequent shift of the same type, in terms of throttle position and engine speed, has a longer duration, the EAT
ECU stores an adaptation for that type of shift in a volatile memory. The adaptation is then included in future pressure
calculations for that type of shift, to restore shift duration to the nominal.

AUTOMATIC GEARBOX - ZF4HP22 - 24
44-20 DESCRIPTION AND OPERATION
P1613
(1)* Solenoid valves
power supply relay,
sticking open or short
circuitLimp home mode in low and high ranges. Shift
pressure to maximum, harsh gear shifts/
engagement.On On
P1705
(39)Transmission high/low
range, implausible
inputNo apparent effect On Off
P1810
(12, 13)Sport/Manual warning
lamp circuit faultLamp fails bulb check or is permanently
illuminated. No effect on gearbox operation.On Off
P1841
(16)* CAN bus fault Maintains current gear in low range, limp
home mode in high range. Shift pressure to
maximum, harsh gear shifts/engagement.On On
P1842
(15)* CAN level monitoring Maintains current gear in low range, limp
home mode in range. Shift pressure to
maximum, harsh gear shifts/engagement.On On
P1843
(17)* CAN time-out
monitoringMaintains current gear in low range, limp
home mode in high range. Shift pressure to
maximum, harsh gear shifts/engagement.On On
P1884
(11)* CAN message:
Engine friction invalidNo apparent effect. On Off
P1884
(18)* CAN message:
Throttle position invalidSubstitute throttle angle of 50% adopted. No
kickdown. Operates in economy modes only.On On
P1884
(19)CAN message: Engine
temperature invalidSubstitute engine temperature derived from
other inputs. No apparent effect.On Off
P1884
(20)CAN message: Road
speed invalidNo apparent effect On Off
P1884
(33, 34)* CAN message:
Engine torque invalidSubstitute engine torque of derived from other
inputs. May affect shift quality.On Off
P1884
(35)* CAN message:
Engine speed invalidMaintains current gear in low range, limp
home mode in high range. Shift pressure to
maximum, harsh gear shifts/engagement.On On
P1884
(37)CAN message: Engine
air intake temperature
invalidNo apparent effect. On Off
P1844
(38)Altitude shift control
invalidNo reduced torque compensation, possible
reduction in performance/ driveability at
altitude or high ambient temperatures.On Off
* = Emissions (OBD II) relevant
†On = MIL illuminates immediately (in all other faults, MIL On = illuminates in the 2nd consecutive drive cycle if
fault still present)Fault code,
OBD II
(TestBook)Fault description Effect Warning lamp
illumination
MIL Sport/
Manual

STEERING
REPAIRS 57-43
Steering column assembly and lock
$% 57.40.01
Remove
1.Remove steering column intermediate shaft.

+ STEERING, REPAIRS, Shaft -
intermediate and universal joint - steering
column.
2.Remove rotary coupler.

+ RESTRAINT SYSTEMS, REPAIRS,
Rotary coupler.
3.Open fascia lower access panel.
4.Remove steering column nacelle.

+ STEERING, REPAIRS, Nacelle -
steering column.
5.Disconnect multiplug and illumination bulb
from passive coil and remove passive coil.
6.Disconnect 2 multiplugs from wiper switch
assembly. 7.Disconnect 2 multiplugs from light switch
assembly.
8.Loosen screw and remove switch assembly.
9.Disconnect ignition switch multiplug.
10.Disconnect multiplug from ignition switch
housing.
11.Release harness from column clip.

STEERING
57-44 REPAIRS
12.Remove 4 nuts securing steering column
assembly to fascia rail and remove steering
column assembly.
13.Remove rubber boot from steering column
assembly.
14.Position steering column assembly in a vice.
15.Remove 2 screws and remove ignition switch.
16.Remove cable tie and remove multiplug from
ignition switch.
17.Centre punch or drill out steering lock shear
bolts.
18.Remove steering lockRefit
1.Position lock to steering column assembly and
fit shear bolts. Do not tighten shear bolts at this
stage.
2.Insert starter key, check operation of steering
lock and that key turns freely.
3.Tighten shear bolts fully and shear heads off.
4.Position ignition switch to column, fit and
tighten screws.
5.Position multiplug to switch and secure with
new cable tie.
6.Fit rubber boot to column.
7.Remove column from vice.
8.Position steering to fascia rail fit nuts and
tighten to 22 Nm (16 lbf.ft).
9.Secure harness to column clip.
10.Position rubber grommet.
11.Close access panel and secure turn buckles.
12.Connect ignition switch multiplugs.
13.Position column switch and tighten clamp
screw.
14.Connect column switch multiplugs.
15.Position passive coil, connect multiplug and
illumination bulb.
16.Fit steering column nacelle.

+ STEERING, REPAIRS, Nacelle -
steering column.
17.Fit rotary coupler.

+ RESTRAINT SYSTEMS, REPAIRS,
Rotary coupler.
18.Close fascia lower access panel.
19.Fit steering column intermediate shaft.

+ STEERING, REPAIRS, Shaft -
intermediate and universal joint - steering
column.

REAR SUSPENSION
64-18 DESCRIPTION AND OPERATION
When SLS compressor operation is required, the ECU provides a battery supply to energise the SLS relay located in
the engine compartment fusebox. When the relay contacts close, a 12 V supply passes through fusible link 9 in the
engine compartment fusebox, through the relay contacts and operates the air supply unit compressor. The ECU will
then supply power to operate one or both air control valve solenoids and/or the exhaust valve solenoid to inflate or
deflate the air springs as required. The compressor does not need to be powered to deflate the air springs.
The ECU also controls the operation of the SLS audible warning, the SLS warning lamp and the ORM warning lamp.
When the ignition is switched to position II, the ECU performs a three second bulb check and illuminates the SLS and
ORM warning lamps in the instrument pack to check for operation. When the system is operating or a fault is sensed
by the ECU, the ECU will operate the appropriate warning lamp and audible warning as required. The audible warning
is operated by the Body Control Unit (BCU) when it receives a signal from the SLABS ECU. The audible warning is
emitted from a speaker at the rear of the instrument pack.
Depressing the ORM switch for a minimum of 0.5 seconds, completes an earth which the ECU uses as a signal to
initiate the ORM if conditions allow. When the ECU starts ORM, the same earth that was completed by the ORM
switch is pulled to earth by the ECU to activate the ORM warning lamp. The ECU checks for a further operation of the
ORM switch by continuously and very quickly removing the earth for the ORM warning lamp. If the ORM switch is
operated for more than 0.5 seconds, the ECU will detect this and de-activate the ORM.
The SLS part of the SLABS ECU also uses the road speed data generated within the SLABS ECU by the ABS system.
Operation of ORM and extended mode are road speed sensitive and use the ABS signal to monitor the vehicle speed.
When the accessory remote handset is used for the SLS lower and raise functions, the handset transmits RF signals
which are received by the same RF receiver used for the alarm/remote door locking system. The RF receiver passes
this data as a 25 Hz PWM signal to the BCU. The BCU then transmits this data to the SLABS ECU as raise or lower
data. TestBook is required to program the BCU for remote handset operation.
SLABS ECU connector pin details

BRAKES
70-26 DESCRIPTION AND OPERATION
Description
General
The handbrake consists of a drum brake, installed on the rear of the transfer box, operated by a cable connected to
a handbrake lever between the front seats.
Handbrake lever
The handbrake lever is mounted on a base plate which attaches to the transmission tunnel. A conventional ratchet
and thumb operated release button are incorporated for locking and unlocking the lever. A warning switch on the base
of the lever operates the brake warning lamp in the instrument pack. While the handbrake is applied the warning
switch connects an earth to the instrument pack which, if the ignition is on, illuminates the brake warning lamp. In
some markets, the instrument pack performs a bulb check of the brake warning lamp each time the ignition is switched
on.
Cable
The handbrake cable consists of inner and outer cables installed between the handbrake lever and the drum brake.
A protective sleeve is installed on the cable to protect the cable from heat from the exhaust system. Handbrake
adjustment is provided by a threaded sleeve installed on the outer cable where it locates in the handbrake lever.
Turning an adjuster wheel, which is keyed to the threaded sleeve and secured by a 'C' clip, alters the effective length
of the outer sleeve and consequently changes the handbrake lever movement needed to apply the drum brake.

INTERIOR TRIM COMPONENTS
76-3-6 REPAIRS
7. Models with veneer trim: Release veneered
console cover and remove cigar lighter
element. Disconnect multiplugs from switch
pack and remove veneered console cover.
8.Remove 2 bolts securing forward edge of
console to transmission tunnel. 9.Release handbrake gaiter from console.
10.Remove clip and clevis pin securing cable to
handbrake lever.
11.Move handbrake to fully upward position.
12.Release electric seat switches from console.
13.Disconnect multiplugs from switches and
remove.
14.Remove 2 bolts securing rear of console to
transmission tunnel.
15.Release centre console from fascia.
16.Disconnect multiplug and bulb from cigar
lighter.

INTERIOR TRIM COMPONENTS
REPAIRS 76-3-7
17.Remove console.
NOTE: Do not carry out further dismantling if
component is removed for access only.
18.Remove 4 screws securing storage bin lid to
console and remove lid.
19.Release cigar lighter body from console and
remove.
Refit
1.Fit and secure cigar lighter body to console.
2.Fit lid to console and secure with screws.
3.Fit console.
4.Connect multiplug and bulb to cigar lighter.
5.Fit centre console to fascia.
6.Fit 2 bolts securing rear of console to
transmission tunnel.
7.Connect multiplugs to seat switches.
8.Fit switches to console.
9.Move handbrake to lowered position.
10.Fit cable to handbrake and secure with clevis
pin and clip.
11.Fit handbrake gaiter to console.
12.Fit bolts securing forward edge of console to
transmission tunnel.
13. Models with veneer trim: Position veneered
console cover and connect multiplugs to switch
pack. Fit cigar lighter element and secure
veneered console cover to console.
14. Models with base trim: Connect multiplugs to
switch pack, fit switch pack to console and
secure with screws.
15. Models with base trim: Fit cover plate to
switch pack, and rubber mat to console.
16.Fit transfer box gaiter and knob to lever.
17.Secure transfer box gaiter to console.
18.Connect multiplug to selector panel, fit and
secure panel to centre console.
19.Fit spacer and knob to gear selector lever.
20. Models from 03MY:Fit both centre console
cup holders.
Console - centre - manual models
$% 76.25.01
Remove
1.Release clips securing gear lever gaiter to
centre console and remove knob and gaiter.
2. Models from 03MY:Remove both centre
console cup holders.
3.Release clips securing transfer box lever gaiter
to centre console and remove knob and gaiter.