1998 JAGUAR X308 engine

Evaporative Emissions - Evaporative Emission Canister Purg
e Valve
Re
moval and Installation
Remov

al
Installation
1. O
pen the engine compartment and fit paintwork protection
sheets.
2. Disconnect the battery.
R
emove the battery cover.
Di

sconnect the battery ground (negative) cable.

3. Di
sconnect the purge valve harness connector.

4. R
emove the two securing nuts.

5. WARNING: B
EFORE PROCEEDING, IT IS ESSENTIAL THAT

THE WARNING NOTES GIVEN IN SECTION 100-00 (UNDER THE
HEADING 'SAFETY PRECAUTIONS') ARE READ AND
UNDERSTOOD.
Disconnect the three valve hoses.
1. Pull off the vacuum pipe.
2. Release the clip and di sconnect the upper vapour
hose.
3. Release the clip and disconnect the lower vapour hose. Plug the hose (note the warning above).
1. R
emove the two mounting rubbers from the old valve and fit to

the new valve.
2. Fitting a new purge valve asse mbly is the reverse of the
removal procedure.

E
lectronic Engine Controls -
Torque spe
cification


Com

ponent
Nm
Engine

coolant temperature sensor
15
- 19
Camshaft position

sensor
9 -
11
Cranksh

aft position sensor
8 -
12
Knock

sensor
31
- 41
O

xygen sensor to downpipe
40
- 50
Inta

ke air temperature sensor (SC only)
30
- 40

El
ectronic Engine Controls -
Electronic Engine Controls
Description and Operation

Th
e engine management system provides optimum control of
the engine under all operating conditions using several
strategically placed sensors and any necessary actuators. Electronic engine control consists of:
engine
control module
throttle posi

tion sensor
engi

ne coolant temperature sensor
cam

shaft position sensor
c

rankshaft position sensor
mass air

flow sensor
intake air temper

ature sensor
kn

ock sensor
heat

ed oxygen sensor
Electronic Engine Control
Engine

Control Module (ECM)

The ECM incorporates a comprehensive monitoring and diagnostic capability including software variations to ensure system
compliance with the latest diagnostic and emissions legislation in different markets. The engine control module controls the
coil on plug ignition system, electronic fuel system, cr uise control and the electronic throttle control system.
The ECM responds to input signals received from sensors relating to engine operatin g conditions and provides output signals
to the appropriate actuators. These outp ut signals are based on the evaluated input signals which are compared with
calibrated data tables or maps held within th e ECM before the output signal is generated.
The ECM needs the following inputs to calibrate the engine properly:
cam
shaft position
It
em
Par
t Number
De
scription
1—Knock

sensor
2—Engine

coolant temperature sensor
3—Cranksh

aft position sensor
4—D

ownstream oxygen sensor
5—Upstream oxygen sensor
6—Camshaft position

sensor
P
arts List
engi

ne rpm
engi

ne coolant temperature
amount

of engine detonation

Throttle Position (TP) Sensor
Location

P
arts List
sen
d
s the ECM a signal indica
ting throttle plate angle
is
the main input to the ECM from the driver
i
s
a dual Hall effect devi
ce mounted on the motor en d of the throttle body
Two additional sensors are attached to the throttle body to provide additional feedback to the ECM: a mechanical guard
position sensor and an accelerator pedal position sensor.
Cam s
haft Position (CMP) Sensor
sen
d
s the ECM a signal indicating camshaft po
sition for fuel synchronization purposes
is
a variable reluctance device mounted on bank 2 cylinder side face
generates a signal when the ri
ng
fitted to the bank 2 inlet
camshaft passes the sensor
Cranksha
ft Position (CKP) Sensor
i
s
a variable reluctance device
mounted on the engine oil pan
Ite
m
Par
t
Number
De
scr
iption
1—Acce
le
rator pedal and mechanic
al guard position sensors
2—Throttle
(blade)
position sensor

generates a signal when th
e dr
ive plate passes the sensor
sen
ds the ECM signals indicating crankshaft position and engine speed
is e

ssential for calculating spark timing
En

gine Coolant Temperature (ECT) Sensor
sen
ds the ECM a signal indicating the temperature of the engine coolant
is a t

emperature dependent resistor with a negative temperature coefficient (resistance changes inversely with
respect to temperature) and is constantly monitored by the ECM
Intake Air Temperature (IAT) Sensor

is m
ounted in the same housing as the MA
F sensor but is not a serviceable item
sen
ds the ECM a signal indicating the temperature of the air entering the engine
is a t

emperature dependent resistor which has a negative
temperature coefficient (its resistance changes inversely
with respect to ambient temperature).
Knock S
ensor (KS)
is a pi
ezo-electric device which sends a signal
to the ECM indicating engine detonation
Between 700 and 6800 rpm, the ECM will retard individual cylinder ignition timing when detonation occurs while allowing
the other cylinders to continue operating normally.
During acceleration, at critical load and speed conditions, the ECM retards ignition timing to prevent the onset of detonation.
H
eated Oxygen Sensor (HO2S)
are
positioned upstream of the catalytic convertor
is equipped with

a heating element wh
ich improves the response time of the sensors during engine warm-up
h
as the ability to generate a voltage signal proportional to the oxygen content of the exhaust gases leaving the
engine
pr
ovides feedback information to the ECM used to calc
ulate fuel delivery and provide optimum gas emissions
Variable V
alve Timing (VVT) Solenoid
R
efer to section 303-01.

Ite
m
Par
t
Number
De
scr
iption
1—Engine

management fuse box
2—Engine
control module (E
CM)
Circuit Diagrams (extracts only)
ECM Su
pply Voltage

It
em
De
scription
1Mechanica

l guard
position sensor (potentiometer)
2Pedal demand sensors (pot
entiometers)
3Thro

ttle position sensor
4Engine

control
module (ECM)
5Throttl
e motor power relay
6EMS fuse box
7Throttl

e motor
T
hrottle Sensors and Control