2002 LAND ROVER DISCOVERY sensor

AUTOMATIC GEARBOX - ZF4HP22 - 24
44-18 DESCRIPTION AND OPERATION
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.
Kickdown
The EAT ECU monitors the input of the throttle position sensor to determine when kickdown is required. When it
detects a kickdown situation, the EAT ECU immediately initiates a down shift provided the target gear will not cause
the engine speed limit to be exceeded.
Torque converter lock-up
The EAT ECU energises the lock-up solenoid valve to engage the lock-up clutch. Lock-up clutch operation is
dependent on throttle position, engine speed, operating mode and the range selected on the transfer box.
High range
Unique lock-up maps, similar to the shift maps, are incorporated in the economy and sport modes for all forward gears.
Engagement and disengagement of the lock-up clutch is dependent on throttle position and engine speed.
Low range
To enhance off road control, particularly when manoeuvring at low speeds, torque converter lock-up does not occur
when there is any degree of throttle opening. When the throttle is closed above a preset engine speed, the lock-up
clutch engages to provide maximum engine braking.
Increased load/reduced torque compensation
To aid performance and driveability in the high range economy mode, the EAT ECU has three adaptive shift and lock-
up maps. These maps delay upshifts and torque converter lock-up similar to the sport mode if the inputs from the
engine indicate:
lA sustained high load on the engine, such as occurs when the vehicle is ascending a steep gradient or towing a
trailer.
lA lower than normal engine torque, such as occurs at altitude or high ambient temperatures.
The EAT ECU monitors the engine inputs and selects the most appropriate adaptive map for the prevailing conditions.
Diagnostics
While the ignition is on, the EAT ECU diagnoses the system for faults. The extent of the diagnostic capability at any
particular time depends on the prevailing operating conditions, e.g. it is not possible to check torque converter lock-
up while the vehicle is stationary, or to check for a short circuit to earth if the circuit concerned is already at a low
potential.
If a fault is detected, the EAT ECU immediately stores a fault code and the values of three operating parameters
associated with the fault. Depending on the fault, there are four possible effects:
lThe fault has little effect on gearbox operation or vehicle emissions. The driver will probably not notice any
change and the warning lamps remain extinguished.
lThe fault has little effect on gearbox operation but may effect vehicle emissions. On NAS vehicles, if the fault is
detected on a second consecutive drive cycle, the MIL illuminates.
lAll gears are available but kickdown does not function. The sport and manual warning lamps flash. The MIL
remains extinguished.
lLimp home mode is selected and vehicle performance is greatly reduced. The sport and manual warning lamps
flash. In all markets, if the fault is detected on a second consecutive drive cycle, the MIL illuminates.

AUTOMATIC GEARBOX - ZF4HP22 - 24
REPAIRS 44-27
11.Drain transfer gearbox oil.

+ MAINTENANCE, PROCEDURES,
Transfer box.
12.Remove front propeller shaft

+ PROPELLER SHAFTS, REPAIRS,
Propeller shaft - front.
13.Remove rear propeller shaft

+ PROPELLER SHAFTS, REPAIRS,
Propeller shaft - rear.
14.Remove and discard 3 bolts securing torque
converter to drive plate.
15.Remove handbrake drum retaining screw and
remove brake drum. 16.Remove 4 bolts from handbrake back plate,
release back plate and tie aside.
17.Remove clip securing high/low ratio selector
cable to transfer gearbox lever, remove 'C' clip
and remove outer cable from gearbox.
18.Disconnect 2 Lucars from differential lock
switch and multiplugs from high/low ratio switch
and neutral sensor.
19.Remove cable tie and multi plug from bracket
to transfer box.

AUTOMATIC GEARBOX - ZF4HP22 - 24
44-30 REPAIRS
14.Secure gearbox breather pipes to bulkhead
clip.
15.Connect multiplugs to high/low ratio switch and
neutral sensor. Connect Lucars to differential
lock switch.
16.Position cable tie and multi plug to transfer box
bracket.
17.Connect high/low ratio cable to transfer box
and secure with retaining clips.
18.Position hand brake back plate and tighten
bolts to 75 Nm (55 lbf.ft).
19.Fit hand brake drum and tighten screw.
20.Remove bolts securing tool LRT-99-008A to
gearbox.
21.Rotate engine to align torque converter, fit new
bolts and tighten to 50 Nm (37 lbf.ft).
22.Fit rear propeller shaft.

+ PROPELLER SHAFTS, REPAIRS,
Propeller shaft - rear.
23.Fit front propeller shaft.

+ PROPELLER SHAFTS, REPAIRS,
Propeller shaft - front.
24.Fill transfer gearbox with oil.

+ MAINTENANCE, PROCEDURES,
Transfer box.
25.Fill automatic gearbox with oil.

+ MAINTENANCE, PROCEDURES,
Automatic gearbox.
26.Position intermediate silencer and secure to
mounting rubbers.
27.Clean silencer and tail pipe mating faces.
28.Position new gasket to tail pipe and tighten
nuts to 25 Nm (18 lbf.ft).
29.Fit exhaust front pipe.

+ MANIFOLDS AND EXHAUST
SYSTEMS - Td5, REPAIRS, Pipe - front.
30.Fit bolt securing closing plate to gearbox
housing and tighten to 7 Nm (5.2 lbf.ft).
31.Fit upper bolts securing gearbox housing to
engine and tighten to 50 Nm (37 lbf.ft).
32.Fit starter motor.

+ CHARGING AND STARTING,
REPAIRS, Starter motor - diesel.
33.Tighten remaining gearbox housing to engine
bolts to 50 Nm (37 lbf.ft).
34.Connect battery earth lead.
35.Fit battery cover and secure with fixings.
36.Check and adjust selector cable.

+ AUTOMATIC GEARBOX - ZF4HP22
- 24, ADJUSTMENTS, Cable - selector.
Gearbox - convertor and transfer
gearbox - V8
$% 44.20.04.99
Remove
1.Release fixings and remove battery cover.
2.Disconnect battery earth lead.
3.Raise vehicle on a ramp.
4.Remove 8 bolts securing centre cross member
and remove cross member.
5.Remove exhaust front pipe.

+ MANIFOLDS AND EXHAUST
SYSTEMS - V8, REPAIRS, Front pipe.
6.Remove 3 nuts securing intermediate silencer
to tail pipe.
7.Release and remove silencer from rubber
mountings.
8.Drain automatic gearbox oil.

+ MAINTENANCE, PROCEDURES,
Automatic gearbox.
9.Drain transfer gearbox oil.

+ MAINTENANCE, PROCEDURES,
Transfer box.
10.Remove front propeller shaft

+ PROPELLER SHAFTS, REPAIRS,
Propeller shaft - front.

AUTOMATIC GEARBOX - ZF4HP22 - 24
REPAIRS 44-31
11.Remove rear propeller shaft

+ PROPELLER SHAFTS, REPAIRS,
Propeller shaft - rear.
12.Remove plug from torque converter housing to
access torque converter bolts.
13.Remove and discard 4 bolts securing torque
converter to drive plate.
14.Remove hand brake drum retaining screw and
remove brake drum.
15.Remove 4 bolts from hand brake back plate,
release back plate and tie aside. 16.Remove retaining clip securing high/low ratio
selector cable to transfer gearbox lever,
remove 'C' clip and remove outer cable from
gearbox.
17.Disconnect 2 Lucars from differential lock
switch and multiplugs from high/low ratio switch
and neutral sensor.
18.Remove cable tie and multiplug from bracket
on transfer gearbox.
19.Release transfer and automatic gearbox
breather pipes from clip at rear of cylinder
block.

AUTOMATIC GEARBOX - ZF4HP22 - 24
REPAIRS 44-33
27.Remove 'C' clip securing selector cable to
gearbox bracket.
28.Remove nut securing selector lever to inhibitor
switch and release lever.
29.Disconnect multiplug from inhibitor switch.
30.Loosen gearbox multiplug locking ring and
disconnect plug.
31.Lower gearbox sufficiently to access bell
housing bolts, take care not to trap any pipes or
cables when lowering gearbox.
32.Remove 14 bolts securing gearbox to engine.
33.With assistance remove gearbox from engine.34.Fit suitable strap to retain torque converter.
Refit
1.Clean gearbox to engine mating faces.
2.Remove torque converter retaining strap.
3.With assistance position gearbox to engine.
4.Fit gearbox bell housing bolts and tighten to 46
Nm (34 lbf.ft)..
5.Connect multiplug to gearbox and tighten
locking ring.
6.Connect inhibitor switch multiplug.
7.Position selector lever to inhibitor switch and
tighten nut to 25 Nm (18 lbf.ft).
8.Position selector cable to gearbox and secure
with 'C' clip.
9.Clean oil pipe unions and fit new 'O' rings.
10.Position and tighten pipe unions to gearbox.
11.Position and tighten oil cooler pipe clamps.
12.Position and tighten oil cooler pipe clip to
engine sump.
13.Position engine RH and LH rear mountings
and tighten bolts to 85 Nm (63 lbf.ft) and nuts to
85 Nm (63 lbf.ft).
14.Secure gearbox breather pipes to bulkhead
clip.
15.Connect multiplugs to high/low ratio switch and
neutral sensor. Connect Lucar connectors to
differential lock switch.
16.Position cable tie and multiplug to transfer
gearbox bracket.
17.Connect high/low ratio cable to transfer box
and secure with retaining clips.
18.Position hand brake back plate and tighten
bolts to 75 Nm (55 lbf.ft).
19.Fit hand brake drum and tighten screw.
20.Remove bolts securing tool LRT-99-008A to
gearbox.
21.Rotate engine to align torque converter, fit new
bolts and tighten to 50 Nm (37 lbf.ft).
22.Fit access plug to torque converter housing.
23.Fit rear propeller shaft.

+ PROPELLER SHAFTS, REPAIRS,
Propeller shaft - rear.

AUTOMATIC GEARBOX - ZF4HP22 - 24
REPAIRS 44-43
Parking pawl assembly.
$% 44.28.07
Remove
1.Drain automatic gearbox oil.

+ MAINTENANCE, PROCEDURES,
Automatic gearbox.
2.Remove transfer gearbox.

+ TRANSFER BOX - LT230SE,
REPAIRS, Transfer box - Diesel.

+ TRANSFER BOX - LT230SE,
REPAIRS, Transfer box - V8.
3.Remove and discard 9 bolts securing extension
housing to gearbox case.
4.Remove extension housing and discard gasket. 5.Remove Torx screw and discard, lift off parking
pawl guide and guide plate.
6.Remove ratchet, spring and pivot pin.
7. Td5 models: Remove spacer from output
shaft.
8.Remove park lock gear.
9.Remove and discard 'O' ring from output shaft.
Refit
1.Clean park lock components.
2.Lubricate and fit new 'O' ring to output shaft.
3.Position park lock gear on the output shaft.
4. Td5 models: Fit the spacer.
CAUTION: Ensure that spacer is fitted on
output shaft - Tdi Models only. If spacer is
omitted, park gear and speed sensor may
move out of position.
5.Position pivot pin, spring and ratchet.
6.Position parking pawl guide and guide plate,
tighten Torx screw to 10 Nm (8 lbf.ft).
M44 1109B
97
8

AUTOMATIC GEARBOX - ZF4HP22 - 24
REPAIRS 44-45
Filter - oil
$% 44.24.07
Remove
1.Remove oil sump gasket.

+ AUTOMATIC GEARBOX - ZF4HP22
- 24, REPAIRS, Gasket - oil sump.
2.Remove Torx screw securing oil pick-up tube
and remove tube.
3.Remove 2 Torx screws securing filter to valve
body and discard 'O' rings.
Refit
1.Clean filter and pick-up tube using a lint free
cloth.
2.Fit new 'O' rings to filter.
3.Position filter and tighten Torx screws to 8 Nm
(6 lbf.ft).
4.Position oil pick-up tube and tighten Torx
screw to 8 Nm (6 lbf.ft).
5.Fit oil sump gasket.

+ AUTOMATIC GEARBOX - ZF4HP22
- 24, REPAIRS, Gasket - oil sump.
Cooler - fluid - Td5
$% 44.24.10
Remove
1.Remove intercooler.

+ ENGINE MANAGEMENT SYSTEM -
Td5, REPAIRS, Intercooler.
2.Disconnect fluid temperature sensor multiplug.
3.Position absorbent cloth under each gearbox
cooler hose connection to collect spillage.
4.Push against coupling release ring and
disconnect both fluid hoses from cooler.
5.Remove screw and release cooler from
radiator.
6.Carefully remove cooler.

AUTOMATIC GEARBOX - ZF4HP22 - 24
44-46 REPAIRS
7.Remove temperature sensor and discard
sealing washer.
Refit
1.Use new sealing washer and tighten
temperature sensor to 14 Nm (10 lbf.ft).
2.Fit cooler, engage with radiator and secure with
screw.
3.Connect temperature sensor multiplug.
4.Ensure connections are clean and fit hoses to
cooler.
5.Fit intercooler.

+ ENGINE MANAGEMENT SYSTEM -
Td5, REPAIRS, Intercooler.
6.Check and if necessary top up gearbox fluid.
Cooler - fluid - V8
$% 44.24.10
Remove
1. If fitted: Remove engine oil cooler.

+ ENGINE - V8, REPAIRS, Cooler -
engine oil.
2.Disconnect fluid temperature sensor multiplug.
3.Position absorbent cloth under each gearbox
cooler hose connection to collect spillage.
4.Push against coupling release ring and
disconnect both fluid hoses from cooler.
CAUTION: Always fit plugs to open
connections to prevent contamination.
5.Remove screw and release cooler from
radiator.
6.Carefully move radiator towards engine and
remove cooler.