manual transmission LAND ROVER DISCOVERY 1999 User Guide

AUTOMATIC GEARBOX - ZF4HP22 - 24
44-14 DESCRIPTION AND OPERATION
EAT ECU connector
EAT ECU connector pin details
Pin No. Description Inputs/Outputs
1 to 4 Not used -
5 Pressure regulator solenoid valve (MV 4) Output
6 Power earth -
7 Not used -
8 Gear position switch, X contacts Input
9 Gear position switch, Z contacts Input
10 to 12 Not used -
13 Transmission high/low switch Input
14 Gearbox output shaft speed sensor, negative Input
15 Gearbox output shaft speed sensor cable screen -
16 CAN, high Input/Output
17 to 24 Not used -
25 Sport mode warning lamp Output
26 Battery power supply Input
27 Not used -
28 Electronics earth -
29 Not used -
30 Shift control solenoid valve (MV 1) Output
31 Diagnostics, K line Input/Output
32 Converter lock-up solenoid valve (MV 3) Output
33 Shift control solenoid valve (MV 2) Output
34 Not used -
35 Not used -
36 Gear position switch, W contacts Input
37 Gear position switch, Y contacts Input
38 to 41 Not used -
42 Gearbox output shaft speed sensor, positive Input
43 Not used -
44 CAN, low Input/Output
45 Mode switch Input
46 to 50 Not used -
51 Manual mode warning lamp Output
52 Not used -
53 Solenoid valves power supply Output
54 Ignition power supply Input
55 Not used -

AUTOMATIC GEARBOX - ZF4HP22 - 24
44-16 DESCRIPTION AND OPERATION
Warning lamps
Warning lamps and selector lever position indication
1Transmission temperature warning lamp (red)
2Gear selector lever position indication3Sport mode warning lamp (green)
4Manual mode warning lamp (green)
Illumination for each warning lamp is provided by a non serviceable LED.

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

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 pack10Body 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 76-3-7
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.

INTERIOR TRIM COMPONENTS
76-3-18 REPAIRS
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.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.

BODY CONTROL UNIT
DESCRIPTION AND OPERATION 86-3-11
Programmable options
The BCU can be programmed with a number of options to satisfy specific market requirements and customer
preferences. The options can be set using TestBook.
Function Option Details
Transmission Manual The vehicle is fitted with manual transmission.
Automatic The vehicle is fitted with automatic transmission.
Front fog lamps None The vehicle is not fitted with front fog lamps.
Main The front fog lamps will operate if the headlamps are on main beam.
No main The front fog lamps will not operate if the headlamps are on main
beam.
Interlocks None The vehicle is not fitted with key, shift or transfer box interlocks.
Shift The vehicle is fitted with key, shift and transfer box interlocks.
No transfer The vehicle is fitted with key and shift interlocks, but not a transfer box
interlock.
Daylight running lamps None The vehicle is not fitted with daylight running lamps.
No main The daylight running lamps are on if the headlamp main beams are off.
No heads The daylight running lights are on with headlamp main and dipped
beams off and the gearbox not in Park.
Programmed wash/ wipe Normal The front wipers operate if the front wash is operated.
No wipe The front wipers do not operate if the front wash is operated.
Key-in warning Disabled The ignition key in audible warning is disabled.
Enabled The ignition key in audible warning is generated if the ignition key is in
and the driver's door is open.
Electric front seats None The vehicle is not fitted with electric front seats.
Normal Electric seat adjustment is available for 45 seconds after the driver's
door opens or if the ignition is on.
Ignition II Electric seat adjustment is available if the ignition is on.
Electric front windows Driver cancel The front windows will be disabled 44 seconds after the driver's door
is opened.
All cancel The front windows will be disabled 44 seconds after any door is
opened.
No cancel The front windows will be disabled when the ignition is turned off.
Heated front screen Fitted The vehicle is fitted with heated front screens.
None The vehicle is not fitted with heated front screens.
Rear windows and sunroof Driver cancel The rear windows and sunroof will be disabled 44 seconds after the
driver's door is opened.
All cancel The rear windows and sunroof will be disabled 44 seconds after any
door is opened.
No cancel The rear windows and sunroof will be disabled when the ignition
switch is turned off.
Gear position indicator
illuminationAlways The automatic gearbox selector illumination is on when the ignition is
on.
Sidelights The automatic gearbox selector illumination is on when the ignition is
on and the sidelights are off.
Hill descent control None The vehicle is not fitted with hill descent control.
Fitted The vehicle is fitted with hill descent control.
Courtesy headlamps Disabled The vehicle is not fitted with courtesy headlamps.
Enabled The vehicle is fitted with courtesy headlamps.
Odometer error warning Disabled The odometer will not flash if there is an odometer error.
Enabled The odometer will flash if there is an odometer error.

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.