2002 LAND ROVER DISCOVERY manual transmission

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.

AUTOMATIC GEARBOX - ZF4HP22 - 24
44-20 DESCRIPTION AND OPERATION
P1601
(4)* ECU, EEPROM
checksumLimp home mode in low and high ranges. Shift
pressure to maximum, harsh gear shifts/
engagement.On On
P1606
(3)* EEPROM No apparent effect On†Off
P1606
(6)* Watchdog No apparent effect On On
P1612
(2)* Solenoid valves power
supply relay, sticking
closed or open circuitLimp home mode in low and high ranges. Shift
pressure to maximum, harsh gear shifts/
engagement.On On
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

BRAKES
DESCRIPTION AND OPERATION 70-3
1ABS sensor
2ABS modulator
3Return pump relay
4SLABS ECU
5Brake lamp relay
6Centre high mounted stop lamp
7LH brake lamp
8RH brake lamp
9Instrument pack
10Body control unit
11Reverse lamp switch (manual gearbox)
12Diagnostic socket
13HDC switch
14Transmission high/low switch
15Centre differential lock switch
16Engine control module
17Battery power supply
18Ignition power supply

BRAKES
70-36 REPAIRS
Cable - handbrake
$% 70.35.25
Remove
1.Remove centre console.

+ INTERIOR TRIM COMPONENTS,
REPAIRS, Console - centre - automatic
models.

+ INTERIOR TRIM COMPONENTS,
REPAIRS, Console - centre - manual
models.
2.Remove clip and clevis pin securing cable to
hand brake lever.
3.Remove brake shoes from hand brake
assembly.

+ BRAKES, REPAIRS, Brake shoes -
handbrake.
4.From below the vehicle, pull handbrake cable
through transmission tunnel.
5.Release handbrake cable from backplate. Refit
1.Fit and secure handbrake cable to backplate.
2.Position hand brake cable through
transmission tunnel.
3.Fit brake shoes to hand brake assembly.

+ BRAKES, REPAIRS, Brake shoes -
handbrake.
4.Align cable to hand brake lever and secure with
clip and clevis pin.
5.Fit centre console.

+ INTERIOR TRIM COMPONENTS,
REPAIRS, Console - centre - automatic
models.

+ INTERIOR TRIM COMPONENTS,
REPAIRS, Console - centre - manual
models.
6.Adjust handbrake.

+ BRAKES, ADJUSTMENTS,
Handbrake.

INTERIOR TRIM COMPONENTS
REPAIRS 76-3-9
16.Remove console.
NOTE: Do not carry out further dismantling if
component is removed for access only.
17.Remove 4 screws securing storage bin lid to
console and remove lid.
18.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 gearbox gaiter and knob to lever.
17.Secure gaiter to console.
18.Fit knob and gaiter to gear lever and secure
gear lever gaiter to console with clips.
19. Models from 03MY:Fit both centre console
cup holders.
Fascia
$% 76.46.23/99
Remove
1.Remove the key from the starter switch.
Disconnect both battery leads, negative lead
first. Wait ten minutes before starting work.
2.Remove radio cassette player.

+ IN CAR ENTERTAINMENT,
REPAIRS, Radio cassette player.
3.Remove steering wheel.

+ STEERING, REPAIRS, Steering
wheel.
4.Remove steering column nacelle.

+ STEERING, REPAIRS, Nacelle -
steering column.
5.Remove centre console.
lFor models with automatic gearbox:

+ INTERIOR TRIM COMPONENTS,
REPAIRS, Console - centre - automatic
models.
lFor models with manual gearbox:

+ INTERIOR TRIM COMPONENTS,
REPAIRS, Console - centre - manual
models.
6.Remove 'A' post trim panels.

INTERIOR TRIM COMPONENTS
76-3-12 REPAIRS
25.Remove 4 bolts securing lower edge of fascia
to mounting brackets on transmission tunnel.
26.Remove 4 bolts securing lower edge of fascia
to brackets on 'A' post.
27.With assistance carefully remove fascia from
vehicle.
28.If renewing fascia, transfer components to new
fascia as necessary.
Refit
1.With assistance carefully fit fascia and tighten
bolts securing lower edge of fascia to 26 Nm
(19 lbf.ft).
2.Tighten bolts securing fascia to body to 26 Nm
(19 lbf.ft).
3.Fit nuts securingfascia to steering column
bracket to 11 Nm (8 lbf.ft).
4.Secure coaxial cables to fascia and secure blue
multiplug to main ICE multiplug.
5. Models with A/C: Connect heater control
multiplug.
6. Models without A/C: Connect temperature
and air distribution inner cables to heater
control levers. Set temperature control knobs to
fully hot, distribution knob to demist position
and, with flap levers fully closed, secure outer
cables to clips on heater casing.
7.Connect multiplugs to blower motor and
passenger air bag (where fitted).
8.Fit glove box and secure with bolts.
9.Connect fascia harness multiplugs to main
harness and fuse box.
10.Position instrument pack and connect
multiplugs.11.Fit instrument pack to fascia and secure with
screws.
12.Position instrument cowl and connect
multiplugs to switches.
13.Fit cowl to clips on fascia and secure with
screws.
14.Fit fascia access panel.

+ INTERIOR TRIM COMPONENTS,
REPAIRS, Panel - fascia access - driver's
side.
15.Fit fascia lower closing panels and secure with
clips.
16.Fit fascia mats.
17.Fit 'A' post trim panels.
18.Fit centre console
lFor models with automatic gearbox:

+ INTERIOR TRIM COMPONENTS,
REPAIRS, Console - centre - automatic
models.
lFor models with manual gearbox:

+ INTERIOR TRIM COMPONENTS,
REPAIRS, Console - centre - manual
models.
19.Fit steering column nacelle.

+ STEERING, REPAIRS, Nacelle -
steering column.
20.Fit steering wheel.

+ STEERING, REPAIRS, Steering
wheel.
21.Fit radio cassette player.

+ IN CAR ENTERTAINMENT,
REPAIRS, Radio cassette player.
22.Connect battery.

INTERIOR TRIM COMPONENTS
REPAIRS 76-3-17
9.Fit drinks tray.

+ INTERIOR TRIM COMPONENTS,
REPAIRS, Drink tray assembly - centre
fascia.
10.Fit and secure radio DIN socket.
11.Fit screw cover to radio aperture.
12.Fit radio cassette player.

+ IN CAR ENTERTAINMENT,
REPAIRS, Radio cassette player.
Carpet - front
$% 76.49.02
Remove
1. Models with premium ICE: Remove power
amplifier.

+ IN CAR ENTERTAINMENT,
REPAIRS, Amplifier - power.
2. Models with premium ICE: Remove CD
autochanger.

+ IN CAR ENTERTAINMENT,
REPAIRS, CD autochanger.
3.Remove centre console.
lFor models with manual gearbox:

+ INTERIOR TRIM COMPONENTS,
REPAIRS, Console - centre - manual
models.
lFor models with automatic gearbox:

+ INTERIOR TRIM COMPONENTS,
REPAIRS, Console - centre - automatic
models.
4.Remove both lower 'A' post trim panels.
5.Remove finisher from both front carpet
retainers.
6.Remove 8 screws securing front carpet
retainers to floor.
7.Remove front carpet retainers.
8.Remove 2 nuts securing main body harness to
transmission tunnel.
9.With assistance release and remove carpet.

INTERIOR TRIM COMPONENTS
76-3-18 REPAIRS
Refit
1.With assistance position carpet.
2.Secure main body harness to transmission
tunnel with nuts.
3.Position front carpet retainers and secure to
floor with screws.
4.Fit finishers to front carpet retainers
5.Fit both lower 'A' post trim panels.
6.Fit centre console.
lFor models with manual gearbox:

+ INTERIOR TRIM COMPONENTS,
REPAIRS, Console - centre - manual
models.
lFor models with automatic gearbox:

+ INTERIOR TRIM COMPONENTS,
REPAIRS, Console - centre - automatic
models.
7. Models with premium ICE: Fit CD
autochanger.

+ IN CAR ENTERTAINMENT,
REPAIRS, CD autochanger.
8. Models with premium ICE: Fit power
amplifier.

+ IN CAR ENTERTAINMENT,
REPAIRS, Amplifier - power.
Carpet - rear
$% 76.49.03
Remove
1. Models with premium ICE: Remove power
amplifier.

+ IN CAR ENTERTAINMENT,
REPAIRS, Amplifier - power.
2.Remove RH front seat.

+ SEATS, REPAIRS, Seat - front.
3.Remove both 'B' post lower trim panels.

+ INTERIOR TRIM COMPONENTS,
REPAIRS, Trim casing - lower - 'B' post.
4.Remove finishers from front and rear carpet
retainers.
5.Remove 12 screws securing front and rear
carpet retainers to floor.
6.Remove front and rear carpet retainers.