2002 LAND ROVER DISCOVERY alternator

HEATING AND VENTILATION
DESCRIPTION AND OPERATION 80-13
Operation
Air distribution
Turning the distribution knob on the control panel turns the control flaps in the heater assembly to direct air to the
corresponding fascia and footwell outlets.
Air temperature
Turning the LH or RH temperature knob on the control panel turns the related blend flaps in the heater assembly. The
blend flaps vary the proportion of air going through the cold air bypass and the heater matrix. The proportion varies,
between full bypass no heat and no bypass full heat, to correspond with the position of the temperature knob.
Blower speed
The blower can be selected off or to run at one of four speeds. While the ignition is on, when the blower switch is set
to positions 1, 2, 3, or 4, ignition power energises the blower relay, which supplies battery power to the blower. At
switch positions 1, 2 and 3, the blower switch also connects the blower to different earth paths through the resistor
pack, to produce corresponding differences of blower operating voltage and speed. At position 4, the blower switch
connects an earth direct to the blower, bypassing the resistor pack, and full battery voltage drives the blower at
maximum speed.
Fresh/Recirculated inlet air
When the recirculated air switch is latched in, the amber indicator LED in the switch illuminates and an earth is
connected to the recirculated air side of the fresh/recirculated air servo motor. The fresh/recirculated air servo motor
then turns the control flaps in the air inlet duct to close the fresh air inlet and open the recirculated air inlets.
When the latch of the recirculated air switch is released, the amber indicator LED in the switch extinguishes and the
earth is switched from the recirculated air side to the fresh air side of the fresh/recirculated air servo motor. The fresh/
recirculated air servo motor then turns the control flaps in the air inlet duct to open the fresh air inlet and close the
recirculated air inlets.
FBH system (where fitted)
The FBH system operates only while the engine is running and the ambient temperature is less than 5
°C (41 °F).
With the engine running and the ambient temperature below 5
°C (41 °F), the air temperature sensor connects the
alternator power supply to the ECU in the FBH unit. On receipt of the alternator power supply, the ECU starts the
circulation pump and, depending on the input from the temperature sensor in the heat exchanger, enters either a
standby or active mode of operation. If the heat exchanger casing temperature is 65
°C (149 °F) or above, the ECU
enters a standby mode of operation. If the heat exchanger casing temperature is below 65
°C (149 °F), the ECU enters
an active mode of operation. In the standby mode, the ECU monitors the heat exchanger casing temperature and
enters the active mode if it drops below 65
°C (149 °F). In the active mode, the ECU initiates a start sequence and
then operates the system at full or part load combustion to provide the required heat input to the coolant.
Start sequence
At the beginning of the start sequence the ECU energises the glow plug function of the glow plug/flame sensor, to
preheat the combustion chamber, and starts the combustion air fan at slow speed. After 30 seconds, the ECU
energises the FBH fuel pump at the starting sequence speed. The fuel delivered by the FBH fuel pump evaporates in
the combustion chamber, mixes with air from the combustion air fan and is ignited by the glow plug/flame sensor. The
ECU then progressively increases the speed of the FBH fuel pump and the combustion air fan to either part or full
load speed, as required by the system. Once full or part load speed is achieved, the ECU switches the glow plug/flame
sensor from the glow plug function to the flame sensing function to monitor combustion. From the beginning of the
start sequence to stable combustion takes approximately 90 seconds for a start to part load combustion and 150
seconds for a start to full load combustion.

HEATING AND VENTILATION
80-14DESCRIPTION AND OPERATION
Coolant temperature control
When the ECU first enters the active mode, it initiates a start to full load combustion. Full load combustion continues
until the heat exchanger casing temperature reaches 60
°C (140 °F), when the ECU decreases the speed of the FBH
fuel pump and the combustion air fan to half speed, to produce part load combustion. The ECU maintains part load
combustion while the heat exchanger casing temperature remains between 54 and 65
°C (129 and 149 °F). If the heat
exchanger casing temperature decreases to 54
°C (129 °F), the ECU switches the system to full load combustion
again. If the heat exchanger casing temperature increases to 65
°C (149 °F), the ECU enters a control idle phase of
operation.
On entering the control idle phase, the ECU immediately switches the FBH fuel pump off, to stop combustion, and
starts a timer for the combustion air fan. After a 2 minute cooldown period, the ECU switches the combustion air fan
off and then remains in the control idle phase while the heat exchanger casing temperature remains above 59
°C (138
°F). If the heat exchanger casing temperature decreases to 59 °C (138 °F), within 15 minutes of the ECU entering the
control idle phase, the ECU initiates a start to part load combustion. If more than 15 minutes elapse before the heat
exchanger casing temperature decreases to 59
°C (138 °F), the ECU initiates a start to full load combustion.
In order to limit the build-up of carbon deposits on the glow plug/flame sensor, the ECU also enters the control idle
phase if the continuous part and/or full load combustion time exceeds 72 minutes. After the cooldown period, if the
heat exchanger casing is still in the temperature range that requires additional heat, the ECU initiates an immediate
restart to part or full load combustion, as appropriate.
Shutdown
The FBH system is de-activated when the alternator power supply to the FBH unit is disconnected, either by the
engine stopping or, if the ambient temperature increases to 5
°C (41 °F) or above, by the contacts in the air
temperature sensor opening. If the system is active when the alternator power supply is disconnected, the ECU de-
energises the FBH fuel pump to stop combustion, but continues operation of the combustion air fan and the circulation
pump to cool down the FBH unit. The cool down time depends on the combustion load at the time the alternator power
input is disconnected.
Cool down times
Diagnostics
The ECU in the FBH unit monitors the system for faults. Any faults detected are stored in a volatile memory in the the
ECU, which can be interrogated by Testbook. A maximum of three faults and associated freeze frame data can be
stored at any one time. If a further fault is detected, the oldest fault is overwritten by the new fault.
The ECU also incorporates an error lockout mode of operation that inhibits system operation to prevent serious faults
from causing further damage to the system. In the error lockout mode, the ECU immediately stops the FBH fuel pump,
and stops the combustion air fan and circulation pump after a cool down time of approximately 2 minutes. Error lockout
occurs for start sequence failures and/or combustion flameouts, heat exchanger casing overheat and out of limit input
voltage. The error lockout mode can be cleared using Testbook, or by disconnecting the battery power supply for a
minimum of 10 seconds.
Start failure/flameout. If a start sequence fails to establish combustion, or a flameout occurs after combustion is
established, the ECU immediately initiates another start sequence. The start failure or flameout is also recorded by
an event timer in the ECU. The event timer is increased by one after each start failure or flameout, and decreased by
one if a subsequent start is successful. If the event timer increases to three (over any number of drive cycles), the
ECU enters the error lockout mode.
Heat exchanger casing overheat. To protect the system from excessive temperatures, the ECU enters the error
lockout mode if the heat exchanger casing temperature exceeds 105
°C (221 °F).
Out of limit voltage. The ECU enters the error lockout mode if the battery or alternator power input is less than 10.5
±
0.3 V for more than 20 seconds, or more than 15.5
± 0.5 V for more than 6 seconds.
Combustion load Cool down time, seconds
Part 100
Full 175

CHARGING AND STARTING
REPAIRS 86-1-1
CHARGING AND STARTING REPAIRS
Alternator - diesel
$% 86.10.02
Remove
1.Remove auxiliary drive belt.

+ CHARGING AND STARTING,
REPAIRS, Belt - auxiliary drive.
2.Release cover and remove nut securing lead
to alternator.
3.Disconnect alternator multiplug.
4.Remove bolt (LH thread) and remove auxiliary
drive belt tensioner. 5.Remove bolt securing support stay to
alternator.
6.Release clip and disconnect oil drain hose from
vacuum pump.
7.Disconnect vacuum pump oil supply pipe from
cylinder head and discard 'O' ring.
8.Remove bolt securing alternator and release
from mounting bracket.
9.Disconnect vacuum hose from vacuum pump.
10.Remove alternator. Take care not to damage
radiator cooling fins.
11.Remove 4 bolts, and remove vacuum pump
from alternator.
CAUTION: Always fit plugs to open
connections to prevent contamination.

CHARGING AND STARTING
86-1-2 REPAIRS
Refit
1.Clean mating faces of alternator and vacuum
pump.
2.Fit vacuum pump to alternator and tighten
bolts to 8 Nm (6 lbf.ft).
3.Position alternator to engine and connect
multiplug.
4.Connect vacuum hose and oil drain hose to
vacuum pump and secure clips.
5.With assistance align alternator to mounting
bracket and fit but do not tighten bolt.
6.Fit bolt securing support stay to alternator and
tighten to 25 Nm (18 lbf.ft) .
7.Tighten bolt securing alternator to mounting
bracket to 45 Nm (33 lbf.ft).
8.Using new 'O' ring, connect oil supply pipe to
cylinder head and tighten to 10 Nm (7 lbf.ft).
9.Connect lead to alternator and tighten nut to 6
Nm (4.4 lbf.ft).
10.Fit auxiliary drive belt tensioner and tighten bolt
to 50 Nm (37 lbf.ft).
11.Fit auxiliary drive belt.

+ CHARGING AND STARTING,
REPAIRS, Belt - auxiliary drive.
Alternator - V8
$% 86.10.02
Remove
1.Remove auxiliary drive belt.

+ CHARGING AND STARTING,
REPAIRS, Belt - auxiliary drive.
2.Remove 2 bolts securing alternator to
mounting bracket.
3.Release alternator from mounting bracket
4.Remove nuts securing alternator cables, and
release cables.

CHARGING AND STARTING
REPAIRS 86-1-3
5.Remove alternator from mounting bracket.
6.Remove pulley from alternator.
Refit
1.Fit alternator pulley and tighten nut to 80 Nm
(59 lbf.ft).
2.Position alternator to mounting bracket.
3.Connect alternator cables and tighten B+ nut to
18 Nm (13 lbf.ft), and D+ nut to 5 Nm (3.7 lbf.ft).
4.Locate alternator in mounting bracket.
5.Fit alternator mounting bolts and tighten to 45
Nm (33 lbf.ft).
6.Fit auxiliary drive belt.

+ CHARGING AND STARTING,
REPAIRS, Belt - auxiliary drive.
Belt - auxiliary drive
$% 86.10.03
Remove
1.Remove viscous fan:
l

+ COOLING SYSTEM - V8,
REPAIRS, Fan - viscous.
l

+ COOLING SYSTEM - Td5,
REPAIRS, Fan - viscous.
2.Turn drive belt tensioner using a 15 mm ring
spanner and release belt from pulleys.
Refit
1.Clean drive belt pulley grooves and ensure
grooves are not damaged.
2.Fit new drive belt around pulleys, ensure belt is
correctly aligned in pulley grooves.
3.With assistance, hold tensioner fully clockwise
and fit drive belt around remaining pulley.
Release tensioner.
4.Fit viscous fan:
l

+ COOLING SYSTEM - Td5,
REPAIRS, Fan - viscous.
l

+ COOLING SYSTEM - V8,
REPAIRS, Fan - viscous.

HARNESSES
REPAIRS 86-7-9
4.Release and disconnect both HS2O sensor
multiplugs.
5.Disconnect CKP sensor multiplug. 6.Disconnect air conditioning compressor
multiplug.
7.Remove 2 nuts securing alternator cables and
release cables.

HARNESSES
86-7-12 REPAIRS
24.Remove bolt securing harness clip to LH side of
engine.
25.Disconnect camshaft sensor and oil pressure
switch multiplugs.
26.Remove engine harness. Refit
1.Position engine harness around engine.
2.Connect oil pressure switch and camshaft
sensor multiplugs.
3.Fit and tighten bolt securing harness to LH side
of engine.
4.Connect both knock sensor multiplugs.
5.Connect battery cable and solenoid cable to
starter motor.
6.Position starter heat shield and secure with
bolt.
7.Clean exhaust flange mating faces, using a
new gasket align exhaust fit nuts and tighten to
60 Nm (44 lbf.ft).
8.Remove stand(s) and lower vehicle.
9.Position harness into footwell and secure
grommet.
10.Connect ECM multiplugs.
11.Position toe board and secure with trim fixings.
12.Connect engine harness to main harness
multiplug and secure earth lead.
13.Connect EVAP solenoid multiplug.
14.Connect both fuse box multiplugs.
15.Position starter lead to fuse box and secure
screw.
16.Fit fuse box cover.
17.Position battery positive lead to battery and
secure nut.
18.Secure harness to coolant rail.
19.Position alternator cables and tighten terminal
B+ to 18 Nm (13 lbf.ft) and terminal D+ to 5 Nm
(3.7 lbf.ft)
20.Connect coolant temperature sensor multiplug.
21.Connect A/C compressor multiplug.
22.Secure harness clip to rear of LH cylinder head.
23.Connect CKP sensor multiplug.
24.Secure injector harness and connect injector
multiplugs.
25.Connect coil multiplugs.
26.Connect and secure HS
2O sensor multiplug
27.Fit upper inlet manifold.

+ MANIFOLDS AND EXHAUST
SYSTEMS - V8, REPAIRS, Gasket - inlet
manifold - upper - Without Secondary Air
Injection.
28.Connect battery earth lead.

HARNESSES
REPAIRS 86-7-13
Harness - engine - diesel
$% 86.70.17
Remove
1.Remove engine acoustic cover.
2.Remove battery carrier.

+ CHARGING AND STARTING,
REPAIRS, Battery carrier.
3.Remove engine compartment fuse box cover.
4.Remove bolts securing battery and alternator
leads to fuse box.
5.Remove bolt securing heater plug lead to fuse
box.
6.Disconnect 2 engine harness multiplugs from
fuse box. 7.Disconnect 2 engine harness multiplugs from
ECM and main harness.
8.Disconnect multiplug from EGR solenoid.
9.Disconnect multiplug from oil pressure switch.