Content .. 146 147 148 149 ..

Range Rover 2. Electrical Manual - part 148

INTRODUCTION

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INTRODUCTION

All components are identified by a letter
followed by an arbitrary number assigned to
the component. The letter assigned to the
component indicates the type of component.

Bulbs, Heated Screens,
Mirror Demisters, Cigar
Lighters, and Heated
Washer Jets

Definition of Vehicle Component Codes

Relays, Solenoids,
Speakers, and Resistors

Motors

Fuse Boxes and Fusible
Links

Switches and Sensors

Electronic Control Units,
Modules, Shields, Diodes,
and Capacitors

B Ć Black

G Ć Green

K Ć Pink
L Ć Light
N Ć Brown

O Ć Orange

P Ć Purple

R Ć Red

SĆ Grey
U Ć Blue
W Ć White

Y Ć Yellow

All wires are identified by letters which indicate
a certain colour. Wire colour and size will only
be shown once if it does not change throughĆ
out the circuit. The following chart explains the
wire colour abbreviations.

Wire Colours

B Ć Black

G Ć Green

K Ć Pink
L Ć Light
N Ć Brown

O Ć Orange

P Ć Purple

R Ć Red

SĆ Grey
U Ć Blue
W Ć White

Y Ć Yellow

Wire Colour Chart

Schematic pages which follow another
schematic page of the same chapter will have
an arrow in the upper left hand corner. There
is no arrow on the first schematic page of a
chapter. Schematic pages which are followed
by another schematic page will have an arrow
in the lower right hand corner. If the page is
the last page of the chapter, there will be a
square instead of an arrow.

Previous and Next Arrows

Page Qualifiers

Schematic pages which are specific to certain
model, option or country variations will have a
small Qualifier" after the Previous Arrow in the
upper left hand corner. For example, a section
might contain pages specific to petrol engines
and some pages specific to diesel engines.
Petrol" will be shown in the upper left hand
corner of petrol specific pages, and Diesel"
will be shown in the upper left hand corner of
diesel specific pages.

INTRODUCTION

REV: 11/2000

Certain abbreviations are used throughout the
Electrical Troubleshooting Manual as circuit
qualifiers. The following list explains all
abbreviations used as qualifiers in the Circuit
Diagrams.

ABS

AntiĆLock Braking System

Circuit Qualifiers

LHD

Left Hand Drive

RHD

Right Hand Drive

NAS

North American Specification

Certain abbreviations are used throughout the
Electrical Troubleshooting Manual as Switch
Position notes.The following list explains all
abbreviations used as Switch Position notes in
the Circuit Diagrams.

Switch Positions

< 100°

Less than 100°

> 100°

More than 100°

CPU

Central Processing Unit

A/C

Air Conditioning

SFI-V8

Sequential Multiport Fuel
Injection (SFI-V8)

Connector, Ground, and Splice Identification:

Connectors, Grounds, and Splices are identified
by a letter followed by a number. Connectors
are identified by C, grounds by E, and splices
by S.

SUFFIX:
A
B
L
R
P
D

For Different Option Variations
For Different Option Variations
Left Side of Vehicle only
Right Side of Vehicle only
Petrol Engine only
Diesel Engine only

Model Year

SEQUENTIAL MULTIPORT FUEL INJECTION (SFI–V8)

CIRCUIT OPERATION

REV: 09/2001

CIRCUIT OPERATION

Sensors

Knock Sensors (X309, X310)

The Knock Sensor is a “Piezo–electric
accelerometer,” i.e. it produces an output voltage
proportional to mechanical vibration produced by the
engine. The Engine Control Module (ECM) (Z132)
receives the signal, filters out any noise and
calculates if the engine is knocking. Due to the cam
and crank signals supplying information regarding
the position of the engine in it’s cycle, the ECM
(Z132) can work out exactly which cylinder is
knocking and retards the ignition on that particular
cylinder until the knock disappears. It then advances
the ignition again to find the optimum ignition point
for that cylinder for those conditions (i.e. fuel type,
air temperature etc.). The ECM (Z132) will be able to
adjust cylinder timing for knock simultaneously, so
that all eight cylinders could have different advance
angles at the same time.

Engine Coolant Temperature Sensor (X126)

The sensor contains two thermistors with negative
temperature co–efficients, i.e. the resistance of the
metal strips varies with temperature. The Engine
Coolant Sensor (X126) signal is vital to correct
engine operation, as the injected fuel quantity is
dependant upon the engine temperature, i.e. richer
mixture at low temperatures.

Crankshaft Position Sensor (X250)

The Engine Control Module (ECM) (Z132) uses the
signal produced by the Crankshaft Position (CKP)
Sensor to determine the exact position of the
crankshaft to enable accurate ignition and fuel
injection timing. The ECM also determines engine
speed at any particular instance through the analysis
of the frequency of fluctuations induced in the CKP
sensor as the teeth of the reluctor ring pass by the
sensor tip.

Camshaft Position Sensor (Z262)

The CMP sensor is a Hall effect sensor which
produces four pulses for every two engine
revolutions. The signal is used in two areas: injector
timing corrections for fully sequential fuelling and
active knock control.

Camshaft operation is essential to continue normal
ignition, i.e. actuate the Fuel Injectors in the normal
sequential order, timing the injection correctly with
respect to top dead centre.

In this way the sequential fuelling will either be
correct, or one engine revolution out of
synchronisation.

Thermostat Monitoring Sensor (X336)

The thermostat monitoring sensor (X336) contains
two negative temperature co–efficient (NTC)
thermistors, (i.e. the resistance of the sensor varies
with coolant temperature). See illustration below.

Resistance (K Ohm)

Temperature (

The thermostat monitoring sensor (X336) is located
in the bottom of the radiator adjacent to the bottom
hose. The sensor monitors the temperature of the
coolant on the radiator side of the thermostat. The
purpose of this monitoring sensor is to determine
whether the thermostat is operating correctly. If the
thermostat is not operating correctly it can delay or
prevent the engine reaching normal operating
temperature.

The thermostat coolant temperature reading is sent
to the ECM (Z132). The ECM compares the engine
coolant temperature reading provided by the ECT
sensor with the thermostat coolant temperature
reading. If the two temperature readings are not
within the pre–set limit, an On–Board Diagnostic
(OBD) code will be generated.

Listed below are the OBD fault codes.

NOTE: Depending upon the engine operating
conditions (i.e. coolant temperature at engine start) a
fault may be indicated by the ECT sensor first,
before the thermostat monitoring sensor (X336).

CDTKA P1117 - Thermistor reading below -33

(-27

CDTKA P1118 - Thermistor reading above
140

C (284

CDTHM P0126 - Difference between radiator
coolant temperature and engine coolant tempe-
ratures too small

On detection of a thermostat monitoring sensor fault
the ECM (Z132) will default to the ECT sensor
signal.

Content .. 146 147 148 149 ..