1999 LAND ROVER DISCOVERY coolant temperature

CONTENTS
CONTENTS 7
ENGINE MANAGEMENT SYSTEM - V8 .................................................. 18-2-1
DESCRIPTION AND OPERATION
Engine management component location - Passenger compartment ............................................ 18-2-1
Engine management component location - Engine compartment .................................................. 18-2-2
Engine management block diagram ............................................................................................... 18-2-4
Description - engine management .................................................................................................. 18-2-6
Operation - engine management .................................................................................................... 18-2-49
DESCRIPTION AND OPERATION
Cruise control component layout .................................................................................................... 18-2-61
Cruise control block diagram .......................................................................................................... 18-2-62
Description - cruise control ............................................................................................................. 18-2-63
Operation - cruise control................................................................................................................ 18-2-74
ADJUSTMENTS
Cable - throttle ............................................................................................................................. 18-2-77
Cable - cruise control .................................................................................................................... 18-2-77
REPAIRS
Spark plugs .................................................................................................................................. 18-2-79
Coil - ignition ................................................................................................................................. 18-2-80
Engine control module (ECM) ......................................................................................................... 18-2-81
Sensor - engine coolant temperature (ECT) ................................................................................ 18-2-82
Sensor - crankshaft position (CKP) ............................................................................................... 18-2-83
Sensor - radiator temperature ....................................................................................................... 18-2-84
Sensor - camshaft position (CMP) ................................................................................................. 18-2-84
Knock sensor (KS) .......................................................................................................................... 18-2-85
Air cleaner assembly ..................................................................................................................... 18-2-86
Element - air filter .......................................................................................................................... 18-2-87
Cable - throttle ................................................................................................................................ 18-2-88
Sensor - Mass Air Flow (MAF) ...................................................................................................... 18-2-89
Throttle Body................................................................................................................................... 18-2-90
Plenum chamber ............................................................................................................................. 18-2-91
Sensor - throttle position (TP) ....................................................................................................... 18-2-91
Valve - idle air control (IACV) ........................................................................................................ 18-2-92
Injectors ......................................................................................................................................... 18-2-92
Actuator - cruise control ................................................................................................................ 18-2-94
Vacuum control unit - up to 03MY................................................................................................... 18-2-94
Vacuum control unit - from 03MY ................................................................................................... 18-2-95
Cable - cruise control ..................................................................................................................... 18-2-96
Switch - cruise control (on/off) ........................................................................................................ 18-2-96
Switch - cruise control (set/resume) ............................................................................................... 18-2-97
Switch - clutch pedal - cruise control ............................................................................................ 18-2-97
ECU - Cruise control ..................................................................................................................... 18-2-98

INTRODUCTION
01-3
Abbreviations and Symbols
A Amperes
AAP Ambient Air Pressure
ABDC After Bottom Dead Centre
ABS Anti-Lock Brake System
ac Alternating current
A/C Air Conditioning
ACE Active Cornering Enhancement
ACEA Association of Constructors of
European Automobiles
AFR Air Fuel Ratio
AP Ambient Pressure
ASC Anti-shunt Control
ATC Air Temperature Control
ATDC After Top Dead Centre
BBDC Before Bottom Dead Centre
BBUS Battery Backed Up Sounder
BCU Body Control Unit
BDC Bottom Dead Centre
bhp Brake Horse Power
BP Boost Pressure
BPP Brake Pedal Position
BS British Standard
BTDC Before Top Dead Centre
C Celsius
CAN Controller Area Network
CD Compact Disc
CDC Centre Differential Control
CDL Central Door Locking
CD - ROM Compact Disc - Read Only
Memory
CFC Chlorofluorocarbon
CHMSL Centre High Mounted Stop Lamp
CKP Crankshaft Position
CLV Calculated Load Value
cm Centimetre
cm
2Square centimetre
cm3Cubic centimetre
CMP Camshaft Position
CPP Clutch Pedal Position
CO Carbon Monoxide
CO
2Carbon Dioxide
CR Common Rail
CVS Canister Vent Solenoid
deg. Degree, angle or temperature
dia. Diameter
DIN Deutsche Industrie Normen
(German Industrial Standards)
dc Direct current
DCV Directional Control Valve
DOHC Double Overhead Camshaft
DTI Dial Test Indicator
DFM Dual Mass Flywheel
DVD Digital Versatile Disc
EACV Electronic Air Control Valve EAT Electronic Automatic
Transmission
EBD Electronic Brake pressure
Distribution
ECD European Community Directive
ECM Engine Control Module
ECT Engine Coolant Temperature
ECU Electronic Control Unit
EDC Electronic Diesel Control
EEPROM Electronic Erasable
Programmable Read Only
Memory
EGR Exhaust Gas Recirculation
EKA Emergency Key Access
EN European Norm
EOBD European On Board Diagnostics
ETC Electronic Traction Control
EUI Electronic Unit Injector
EVAP Evaporative Emission
EVR Electronic Vacuum Regulator
F Fahrenheit
FBH Fuel Burning Heater
FIP Fuel Injection Pump
FTC Fast Throttle Control
g Gramme or Gravity
hHour
hc High compression
HC Hydro Carbons
HDC Hill Descent Control
HDPE High Density Polyethylene
HFS Heated Front Screen
Hg Mercury
HO2S Heated Oxygen Sensor
HMW High Molecular Weight
HRW Heated Rear Window
ht/HT High tension
IACV Idle Air Control Valve
IAT Intake Air Temperature
ICE In-Car Entertainment
i.dia. Internal diameter
IDM Intelligent Driver Module
in3Cubic inch
ILT Inlet Throttle
ISO International Organisation for
Standardisation
k Thousand
kg Kilogramme
km Kilometre
km/h Kilometres per hour
kPa KiloPascal
KS Knock Sensor
lLitre
lbf.in Pounds force inches
lbf/in
2Pounds per square inch
lbf.ft Pounds force feet

GENERAL DATA
04-9
Cooling system - Td5
Type Pressurised, spill return partial flow, thermostatically controlled
Cooling fans 11 blade axial flow on viscous coupling and 11 blade axial flow electric
Electric cooling fan switching points:
For A/C system:
⇒ On When vehicle speed is 50 mph (80 km/h) or less and ambient
temperature is 28 °C (82 °F) or more
⇒ Off When vehicle speed increases to 62.5 mph (100 km/h) or ambient
temperature decreases to 25 °C (77 °F)
For engine cooling during normal running:
⇒ On 110 °C (230 °F)
⇒ Off 105 °C (221 °F)
For engine cooling at ignition off (to counteract heat
soak):
⇒ On If, within 10 seconds of ignition off, engine coolant temperature is 105
°C (221 °F) or more
⇒ Off After 10 minutes or if engine coolant temperature decreases to 100 °C
(212 °F)
Coolant pump Centrifugal impeller, belt driven from crankshaft
Thermostat Waxstat with pressure relief valve
Thermostat opening temperature:
⇒ Initial opening 82 °C (179 °F)
⇒ Fully open 96 °C (204 °F)
Expansion tank cap relief valve - system operating
pressure1.4 bar (20.3 lbf.in
2)
Fuel cooler thermostat opening temperature 82°C (179°F)

GENERAL DATA
04-10
Cooling system - V8
Type Pressurised, spill return, thermostatically controlled water and
antifreeze mixture. Vertical flow radiator with remote header tank and
pump assisted
Cooling fans 9 blade axial flow on viscous coupling and 11 blade axial flow electric
Electric cooling fan switching points:
For A/C system:
⇒ On When vehicle speed is 50 mph (80 km/h) or less and ambient
temperature is 28 °C (82 °F) or more
⇒ Off When vehicle speed increases to (62.5 mph (100 km/h) or ambient
temperature decreases to 25 °C (77 °F)
For engine cooling during normal running:
⇒ On 100 °C (212 °F)
⇒ Off 94.5 °C (202 °F)
For engine cooling at ignition off (to counteract heat
soak):
⇒ On If, within 10 seconds of ignition off, intake air temperature is 60 °C (140
°F) or more and engine coolant temperature is 110 °C (230 °F) or more
⇒ Off After 10 minutes or if engine coolant temperature decreases to 100 °C
(212 °F)
Coolant pump Centrifugal impeller, belt driven from crankshaft
Coolant pump drive ratio 1.293 : 1
Coolant pump output at 1000 rev/min 10 litres/min (2.64 US galls/min) at 0.7 bar (10 lbf.in
2)
Thermostat Waxstat with pressure relief valve
Thermostat operating temperature:
⇒ Initial opening 82 °C (179 °F)
⇒ Fully open 96 °C (204 °F)
Expansion tank cap relief valve - system operating
pressure1.4 bar (20 lbf.in
2)

CAPACITIES, FLUIDS, LUBRICANTS AND SEALANTS
09-2
Fluids
Anti-freeze
Use Havoline Extended Life Coolant (XLC), or any
ethylene glycol based anti-freeze (containing no
methanol) with only Organic Acid Technology (OAT)
corrosion inhibitors, to protect the cooling system
CAUTION: No other anti-freeze should be used
with Havoline Extended Life Coolant.
The cooling system should be drained, flushed and
refilled with the correct amount of anti-freeze solution
at the intervals given on the Service Maintenance
Check Sheet.
After filling with anti-freeze solution, attach a warning
label to a prominent position on the vehicle stating
the type of anti-freeze contained in the cooling
system to ensure that the correct type is used for
topping-up.
Brake/Clutch fluid
Use only DOT 4 brake fluid.
PAS fluid
Use Texaco cold climate power assisted steering
fluid PSF 14315.
ACE fluid
Where ambient temperature falls below -20° C (-4°
F), use only Texaco cold climate power assisted
steering fluid PSF 14315. Where ambient
temperature remains above -20° C (-4° F), use either
Texaco cold climate power assisted steering fluid ,
Dexron 11 or Dexron 111 non-synthetic fluid.
Air conditioning
Use only refrigerant R134a.
Refrigerant oil
Use only Nippon Denso ND-oil 8.
Refrigerant oil absorbs water and must not be stored
for long periods. Do not pour unused oil back into the
container.
NOTE: The total quantity of refrigerant oil in the
system is 180 ml.
CAUTION: Do not use any other type of
refrigerant oil.
Anti-Freeze Concentration
The overall anti-freeze concentration should not fall,
by volume, below 50% to ensure that the anti-
corrosion properties of the coolant are maintained.
Anti-freeze concentrations greater than 60% are not
recommended as cooling efficiency will be impaired.
The following recommended quantities of anti-freeze
will provide frost protection to -48°C (-53°F):
Engine - TD5
Engine - V8
Concentration 50%
Amount of Anti-freeze 4 litres
Concentration 50%
Amount of Anti-freeze 6.5 litres
13.5 pts (US)

CAPACITIES, FLUIDS, LUBRICANTS AND SEALANTS
09-4
Gearbox oil
Manual Gearbox: Use Texaco MTF 94 oil for refill
and topping-up.
Automatic Gearbox: Use Texamatic 9226, ATF
Dexron 11D or Dexron 111 for refill and topping-up
Transfer box
Use Texaco Multi-Gear 75W/90R or oil meeting
specification API GL5.
Front and rear axles
Use Texaco Multi-Gear 75W/90R.
Air Conditioning
Use lubricating oil Nippon Denso ND-8.
General Greasing
Use Multipurpose Lithium Base Grease N.L.G.I.
consistency No. 2.
Bonnet latch
Lubricate cable and latch with oil.
Sealants
The following table lists those sealants which are
used during repair / overhaul procedures covered in
this manual; it is essential that the sealant specified
for a particular procedure is used at all times.
Component Application Land Rover
Part No.
Td5 Engine Timing chain fixed
guide Allen screwSTC 50552
Td5 Engine Camshaft cover
gasket joint lineSTC 50550
Td5 Engine Oil pick-up strainer
Torx screwsSTC 50552
Td5 Engine Oil pump drive
sprocket retaining
boltSTC 50552
Td5 Engine Timing chain cover,
crankshaft rear oil
seal and sump
gasket joint linesSTC 50550
Td5 Engine Oil pressure relief
valve plugSTC 50552
Td5 Engine Camshaft carrier to
cylinder headSTC 4600
Td5 Engine Timing cover STC 50550
V8 Engine Sump gasket to
cylinder blockSTC 50550
V8 Engine 'V' grooves at end
of cylinder head -
Inlet manifold
gasketSTC 50550
V8 Engine Cruciform seal
endsSTC 50550
V8 Engine Dipstick tube STC 50554
V8 Engine Timing cover bolts STC 50552
Engine
Management
System - V8Engine coolant
temperature (ECT)
sensor threadsSTC 50552
Manifolds and
Exhaust
System - V8'V' grooves at end
of cylinder head -
Inlet manifold
gasketSTC 50550
Manual
Gearbox -
R380Gear selector
housingSTC 4404
Manual
Gearbox -
R380Selector housing
boltsSTC 50552
Manual
Gearbox -
R380Input shaft oil seal
housingSTC 4404
Manual
Gearbox -
R380Reverse inhibitor
shaft threadsSTC 50552

EMISSION CONTROL - V8
17-2-26 DESCRIPTION AND OPERATION
Secondary Air Injection System
The secondary air injection (SAI) system comprises the following components:
lSecondary air injection pump
lSAI vacuum solenoid valve
lSAI control valves (2 off, 1 for each bank of cylinders)
lSAI pump relay
lVacuum reservoir
lVacuum harness and pipes
The secondary air injection system is used to limit the emission of carbon monoxide (CO) and hydrocarbons (HCs)
that are prevalent in the exhaust during cold starting of a spark ignition engine. The concentration of hydrocarbons
experienced during cold starting at low temperatures are particularly high until the engine and catalytic converter
reach normal operating temperature. The lower the cold start temperature, the greater the prevalence of
hydrocarbons emitted from the engine.
There are several reasons for the increase of HC emissions at low cold start temperatures, including the tendency for
fuel to be deposited on the cylinder walls, which is then displaced during the piston cycle and expunged during the
exhaust stroke. As the engine warms up through operation, the cylinder walls no longer retain a film of fuel and most
of the hydrocarbons will be burnt off during the combustion process.
The SAI pump is used to provide a supply of air into the exhaust ports in the cylinder head, onto the back of the
exhaust valves, during the cold start period. The hot unburnt fuel particles leaving the combustion chamber mix with
the air injected into the exhaust ports and immediately combust. This subsequent combustion of the unburnt and
partially burnt CO and HC particles help to reduce the emission of these pollutants from the exhaust system. The
additional heat generated in the exhaust manifold also provides rapid heating of the exhaust system catalytic
converters. The additional oxygen which is delivered to the catalytic converters also generate an exothermic reaction
which causes the catalytic converters to 'light off' quickly.
The catalytic converters only start to provide effective treatment of emission pollutants when they reach an operating
temperature of approximately 250°C (482°F) and need to be between temperatures of 400°C (752°F) and 800°C
(1472°F) for optimum efficiency. Consequently, the heat produced by the secondary air injection “afterburning”,
reduces the time delay before the catalysts reach an efficient operating temperature.
The ECM checks the engine coolant temperature when the engine is started in addition to the elapsed time since the
engine was last started. The engine coolant temperature must be below 55°C (131°F) for the SAI pump to run.
NOTE: The ambient air temperature must also be above 8
°C (46°F) for the SAI pump to run.
Also, depending on the long term 'modelled' ambient temperature determined by the ECM, the minimum elapsed time
required since the last engine start can be up to 8.25 hours. The period of time that the SAI pump runs for depends
on the starting temperature of the engine and varies from approximately 96 seconds at 8°C (46°F) to 30 seconds at
55°C (131°F).
Air from the SAI pump is supplied to the SAI control valves via pipework and an intermediate T-piece which splits the
air flow evenly to each bank.
At the same time the secondary air pump is started, the ECM operates a SAI vacuum solenoid valve, which opens to
allow vacuum from the reservoir to be applied to the vacuum operated SAI control valves on each side of the engine.
When the vacuum is applied to the SAI control valves, they open simultaneously to allow the air from the SAI pump
through to the exhaust ports. Secondary air is injected into the inner most exhaust ports on each bank.
When the ECM breaks the ground circuit to de-energise the SAI vacuum solenoid valve, the vacuum supply to the
SAI control valves is cut off and the valves close to prevent further air being injected into the exhaust manifold. At the
same time as the SAI vacuum solenoid valve is closed, the ECM opens the ground circuit to the SAI pump relay, to
stop the SAI pump.
A vacuum reservoir is included in the vacuum line between the intake manifold and the SAI vacuum solenoid valve.
This prevents changes in vacuum pressure from the intake manifold being passed on to cause fluctuations of the
secondary air injection solenoid valve. The vacuum reservoir contains a one way valve and ensures a constant
vacuum is available for the SAI vacuum solenoid valve operation. This is particularly important when the vehicle is at
high altitude.

EMISSION CONTROL - V8
DESCRIPTION AND OPERATION 17-2-27
The ECM connector and pins pertinent for secondary air injection are listed in the following table:
Secondary Air Injection System Components
The secondary air injection (SAI) system components (where fitted) are described below:
Secondary Air Injection (SAI) Pump
1SAI pump cover
2Foam filter3SAI pump
4Pressurised air to exhaust manifolds
The SAI pump is attached to a bracket at the rear RH side of the engine compartment and is fixed to the bracket by
three studs and nuts. The pump is electrically powered from a 12V battery supply via a dedicated relay and supplies
approximately 35kg/hr of air when the vehicle is at idle in Neutral/Park on a start from 20°C (68°F).
Air is drawn into the pump through vents in its front cover and is then passed through a foam filter to remove
particulates before air injection. The air is delivered to the exhaust manifold on each side of the engine through a
combination of plastic and metal pipes.
Connector / Pin No. Description Signal type Control
C0635-23 Main relay output Output drive Switch to ground
C0636-4 Secondary air injection vacuum solenoid
valve controlOutput, drive Switch to ground
C0636-16 Secondary air injection pump relay control Output drive Switch to ground
C0636-21 Coolant temperature (ECT) sensor Ground 0V
C0636-22 Coolant temperature (ECT) sensor Input signal Analogue 0 - 5V
C0637-20 MIL "ON" Output drive Switch to ground
M17 0204
1
4
2
3