sensor JAGUAR X308 1998 2.G Workshop Manual

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.

is
of the 'hot-wire' type (the resistan
ce of the wire varies as incoming air passing over it has a cooling effect)
provides f
eedback to the ECM to perm
it monitoring of mass air flow
is NO
T serviceable, necessitating its renewal should a fault occur
Mass Air Flo
w (MAF) Sensor
Location

P
arts List
It

em
Par
t Number
De
scription
1—PI032

VVT solenoid 2
2—PI027

KS 2
3—PI004

ECT sensor
4—PI026

KS 1
5—PI031

VVT solenoid 1
6—PI035

MAFS (on vehicle)
7—PI050

Generator
8—PI040

Oil pressure switch
9—PI018

to PI021 Bank 1 Ignition coils 1 to 4
PI022 to PI025 Bank 2 Ignition coils 1 to 4
10—PI006
Throttle valve position sensor
11—PI002 En

gine management harness (on vehicle)
12—PI001 En

gine management harness (on vehicle)
13—PI033

Throttle valve motor
14—PI034

EGR valve (where fitted)
15—PI015 CM

P sensor
16—PI042

Accelerator pedal and
mechanical guard sensors
17—PI007
to PI010 Bank 1 Injectors 1 to 4 PI011 to PI014 Bank 2 Injectors 1 to 4
18—PI037

Compressor lock
sensor (where fitted)
19—PI036
Compressor clutch
20—PI017 CK

P sensor
E
ngine Harness Connectors
Location

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

Ite
m
Part
Number
Descr
iption
1—Knock
sensors, banks 1 and 2

2—Engine
control module (E
CM)
Knock
Sensor

It
em
Par
t Number
De
scription
1—Cranksh

aft position sensor
2—Engine

control module (ECM)
Crankshaft Posi
tion sensor

Ite
m
Par
t
Number
De
scr
iption
1—Camshaft position

sensor
2—Engine
control module (E
CM)
Cams
haft
Position sensor

It
em
Par
t Number
De
scription
1—MAF

assembly
2—MAF s

ensor
3—IAT se

nsor
4—Engi

ne to vehicle harness connector
5—EMS fuse box


6—Engine

control module (ECM)
7—Charge air cool

er -
IAT sensor (superchar
ged engin
es only)

MAF
and IAT Sensors

It e
m
De
scr
iption
1Engine
c
ontrol
module (ECM)
2Do
wnstream oxygen sensor (A)
3Upstream heated ox
ygen sensor
(A)
4D
o
wnstream oxygen sensor (B)
5Upstream heated ox
ygen sensor (B)
6Engine
management fuse box
Ox
yg
en Sensors

CAUTIO
N: When probing connectors to take
measurements in the course of the pinpoint tests, use the adaptor kit,
part number 3548-1358-00.
• NOTE: When performing electrical voltag e or resistance tests, always use a digital multimeter (DMM) accurate to 3
decimal places, and with an up-t o-date calibration certificate. When testing resistance, always take the resistance of the
DMM leads into account.
• NOTE: Check and rectify basic faults before beginning diagnostic ro utines involving pinpoint tests.
Sym
ptom Chart
Sym

ptom
(general)
S y
mptom (specific)
Possib
l
e source
Acti
o
n
No
n
-Start
Engine
does not cran
k
Starter relay ECM relay Batt
ery Park
/Neutral
switch
Starting system

Harness damage
Engine s
iezed
Check r
e
lay dates. Check
for DTCS. For starting
system,
REFER to Section 303
-06 Sta r
ting System
.
F or ECM
relay tests, GO to Pinpoint Test
AD.
.
F o
r battery information,
REFER to Section 414
-0 1
Battery, Mounting and

Cables.
Fo r

Park/Neutral tests, GO to Pinpoint Test AC.
. Fo
r engine information,
REFER to Section 303
-01 En
gine
.
Engine cranks, but does
not fireSecurity
syst
em /Immobiliser
engaged
Thr o
ttle contaminated
Harness damage
Fu
el pump relay
Fue
l
system
R
e
fer to service action
S491
Contact dealer techni
cal
support for information
on security system. For fuel system,
REFER to Section 303
-0 4
Fuel Charging and
Controls.
Check bull etins for throttl
e cleaning procedure.
Check service actions.
Engine cranks an d
fires,
but will not start
F u
el pump relay
Thr
o
ttle contaminated
Purge
val
ve
Fue
l
pump
Engine coolan
t
temperature

(ECT) sensor
Spark plugs
fouled
Ignition coil
fail
ure(s)
Check f
o
r water ingress
into spark plug wells
HT sh o
rt to ground
(tracking) check rubber
boots for cracks/damage
Cyli
nder compression loss
(short-term. Refer to bulletin; 303-52)
Re
fer to service action
S491
Fo
r fuel pump relay tests,
REFER to Section 303
-0 4
Fuel Charging and
Controls.
. Check bulletins for throttl
e cleaning procedure.

Check fuel pressure. Refe r to Technical service
bulletins. For ECT sensor tests, GO to Pinpoint Test C.
. Fo
r ignition system,
REFER to Section 303
-07 En
gine Ignition
.
Check bulletins an d service a
ctions.
Di
f
ficult to
start
D iff
icult to start cold
Roc
h
ester valve
Batt
ery Thro
ttle contaminated
Fue
l
pump
Engine coolan
t
temperature

(ECT) sensor
Purge val
ve
Cyl
i
nder compression loss
(short-term. Refer to bulletin; 303-52)
Blocked part-load breather (s
ervice action S474)
R
e
fer to service action
S491
For R
ochester valv
e test, GO to Pinpoint Test AE.
. Fo
r battery information,
REFER to Section 414
-0 1
Battery, Mounting and

Cables.
Check bull etins for throttl
e cleaning procedure.
Check fuel pressure. For ECT sensor circuit tests,
GO to Pinpoint Test C.
. F
or evaporative
emissions tests,
REFER to Section 303
-1 3
Evaporative
Emiss
i
ons
.
R e
fer to bulletins for co
mpression information,
and service actions for part-load breather procedure and compressions.
Diff
icult to start hot
Roc
h
ester valve
Purge
val
ve
Thr
o
ttle contaminated
F
or R
ochester valv
e test, GO to Pinpoint Test AE.
. F
or evaporative emissions tests,
REFER to Section 303
-1 3
Evaporative