1998 JAGUAR X308 emission

diverter val
ve (if fitted) and oil filter.
Main
bearings
which are grooved in the upper positions and plain in
the lower positions. They are manufactured from
aluminium / tin material.
A c
rankshaft with under
cuts and rolled fillets for extra strength.
Fracture
-split connecting rods in sintered-forged steel.
Brackets
bolted to the front of
the cylinder
block are used to mo unt all accessories.
A sin
gle, seven ribbed vee belt
drives the accessories.
An au
tomatic belt tensioner for the front accessory drive,
incorporating a wear indicator.
An advanced en
gine management system inco
rporating electronic throttle control.
The un
it meets the requirements of the CARB OBDII USA legislation.
Ancillary Systems
The an
ci
llary systems, driven by the engine, each have a
detailed Description and Operation along with Diagnostic
Procedures, and Removal and Installation instructions ; refer to the following sections of this manual:
Power Steeri
ng Pump - Section 211-02
Ai
r Conditioning Compressor - Sectio
n 412-03
Engine
C
ooling Pump - Section 303-03
Generator
- Sectio
n 414-02
The drive belt, idler pulley and automatic tensioner are described in Section 303-05.
The engine starting system is described in Section 303-06.
En
gine Management and Emission Control System
Engine Control Modu
le (ECM)
Engine
management and exhaust emissions are controlled by the ECM, which has the
following main functions:
Fu
el injection
Idle
s
peed
Ignition Ev

aporative loss system
Engine
cooling fans Clim
ate control compressor clutch demand
The microprocessor within the ECM receiv es signals from various sensors and other modules and uses a pre-determined
program to compute engine management functions.
Adaptive functions are incorporated in the ECM to cater for co ntinuous adjustments to its computations to suit prevailing
conditions. Because the system also controls emissions to suit all modes, neither CO levels nor idle speed require service
attention or adjustment, except if an error should occur.
On Board Diagnostics are controlled by the ECM with the continuous monitoring of incoming signals and the subsequent
verification against what the module expects to 'see'. Should a si gnal be incorrect or missing, the ECM will substitute a fixed
value to provide the 'limp home mode' and alert the driver of the problem. Fixed values may be adopted for:
Transmission oil
temperature
Mechanica
l
guar
d position
Throttle blade angle Camshaft position

Inta
k
e air temperature
Diagnostic trouble codes (DTC), including OBD II codes, are stored in the ECM memo ry and can be read by an appropriate
retrieval tool.
Should either the ECM or TCM fa il, ensure that the control housing cooling fan is operating correctly. Failure of the cooling
fan MUST be rectified before renewing a control module and details of a fa n failure should accompany a returned control
module.

E
ngine Management System Components
Electronic Throt
tle
The
electronic throttle assembly, in resp
onse to signals from both the driver and the ECM, adjusts idle speed, sets the
throttle valve to the position requested by the driver's accelerator / throttle pedal, cruise and traction control, power
limitation and catalyst warm-up.
Mass
Air Flow Meter
The sensor i
s located in the air flow mete
r assembly and outputs an analogue voltag e to the ECM. This sensor measures air
flow into the engine inlet system and is calibrated to measure kg / hour.
In
take Air Temperature
Th
e intake air temperature sensor is loca
ted in the air flow meter assembly and outputs an analogue voltage to the ECM.
The ECM will substitute a default value eq ual to 50°C should this sensor fail.
Fuel Injectors
The eigh
t bottom fed fuel injectors are located in the fuel rails. Th
e fuel injectors are electromagnetic solenoid valves
controlled by the ECM. The pulse time for the injector combined with the fuel pr essure determines the volume of fuel
injected to the manifold.
Fue
l Delivery
The fu
el pump provides fuel to the fuel rail where the circulat
ing pressure is controlled by a pressure regulator valve; excess
fuel is returned to the fuel tank.
The pressure regulator valve is controlled by manifold depression so that fuel delivery pressure is maintained at
approximately 3 bar above manifold pressure.
Fuel Pump
Relay
The ECM controls thi

s component for normal
engine running. The security system may disable this relay via communication
with the ECM.
Fuel Lev
el Sensing
The tank fuel

is measured by the fuel le
vel sensor . This signal is used by the ECM as an in put to certain diagnostics.
Eva
porative Valve
Excess vapour

formed in the fuel tank is
absorbed into the evaporative emission pu rge control canister. While the engine is
running, the fuel absorbed in the canister is gradually purged back into the engine. The rate of purging is governed by
engine operating conditions and vapour concentration level. Operating conditions which affect the purge rate are:
2—Purge
valve
3—Engine

torque reduction
4—E

lectronic throttle assembly
5—Coo

ling fans
6—Ignition amplifier driver
7—Engine overspeed
8—Cli

mate control compressor clutch
9—O

BDII information (J1962, CAN, ISO)

10—F
uel pump relay
11—Heat

ed oxygen sensor
12—Vari

able valve timing
13—MIL sw

itching



ECM Out
puts
It

em
Par
t Number
De
scription
1—Exhaus

t gas recirculation

Thi
s sensor uses a piezo-electric sensing element to detect kn
ock which may occur under acceleration at critical conditions.
Should detonation be present the ECM will retard ignition timing of individual cylinders.
Exhaust G
as Recirculation
The EGR
valve (where fitted) reduces NOx
emissions by recirculating a portion of the exhaust gases back into the inlet
manifold.
Heated Oxyg
en Sensors
The h
eated oxygen sensors, one per bank, are situated upstream of the catalysts. Integral
to the sensors are heaters
(under ECM control) which allow the sensor s to reach their operating temperature as soon as possible after engine start. A
comparison between the level of oxygen in the exhaust gas to that in the atmosphere produces an output signal. This signal
is used by the engine closed loop fuel strategy to make fuelling corrections and so control overall emission levels.
Oxygen Sensors

Thes
e sensors, one per bank, are situated downstream of the
catalyst. The comparison of upstream and downstream signals
allows determination of cata lyst conversion efficiency.




Knock Sensor

CAUTI
ON: 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.
Sy
mptom Chart
Sy

mptom
Possib
le source
Acti
on
Engine

cranks, but does not fire
Secu
rity system /Immobiliser
engaged
Thr
ottle contaminated
Harness damage


F

uel pump relay
Fue

l system
R

efer to service action S491

Contact dealer techn
ical
support for information
on security system. Chec k bulletins for throttle
cleaning procedure. For fuel pump relay circuit
tests, GO to Pinpoint Test E.
.
Check fuel pressure,


REFER to Section 310
-00
Fuel System
- Gen
eral
Informati

on
.
Chec
k for associated DTCs
. Check service actions.
Engine
cranks and fires, but will
not start
F
uel pump relay
Thr

ottle contaminated
Purge

valve
Fue

l pump
Engine coolan

t temperature
(ECT) sensor
Spark plugs
fouled
Ignition coil

failure(s)
Check f

or water ingress into
spark plug wells
HT sho
rt to ground (tracking)
check rubber boots for cracks/damage
Cyl
inder compression loss
(short-term. Refer to bulletin;
303-52)
R
efer to service action S491

F
or fuel pump relay tests,
GO to Pinpoint Test E.
.
Check bull
etins for throttle cleaning procedure. For

evaporative emissions tests,
REFER to Section 303
-1
3 Evaporative Emissions
. Chec

k fuel pressure,
REFER to Section 310
-00
Fuel System
- Ge
neral
Informati

on
.
F
or ECT sensor circuit tests,
REFER to Section 303
-14 Elec
tronic Engine
Controls.
For ign
ition system,
REFER to Section 303
-07
Engine Ignition
.
Check bulletins an d service
actions.
D

ifficult to start cold
Roc
hester valve
Batt

ery
Thr

ottle contaminated
Fue

l pump
Engine coolan

t temperature
(ECT) sensor
Purge
valve
Cyl

inder compression loss
(short-term. Refer to bulletin;
303-52)
Blocked part-load breather (
service action S474)
R

efer to service action S491

F
or rochester valve tests,
REFER to Section 303
-14 Elec
tronic Engine
Controls.
F
or battery information,
REFER to Section 414
-0
1 Battery, Mounting and
Cables.
Check bull
etins for throttle cleaning procedure.
Check fuel pressure,
REFER to Section 310
-00
Fuel System
- Ge
neral
Informati

on
.
F
or ECT sensor circuit tests,
REFER to Section 303
-14 Elec
tronic Engine
Controls.
For evaporat
ive emissions tests,
REFER to Section 303
-1
3 Evaporative Emissions
. Check bulletins an

d
service actions.
D
ifficult to start hot
Roc
hester valve
Purge

valve
Thr

ottle contaminated
Fue

l pump
Engine coolan

t temperature
(ECT) sensor
Blocked part-load breather (
service action S474)
Injec

tor leak
F
or Rochester
valve test,
REFER to Section 303
-14 Elec
tronic Engine
Controls.
Fo
r injector leak test, REFER to technical service
bulletin, 303-39. Check fuel pressure, For evaporative emissions components,
REFER to Section 303
-1
3 Evaporative Emissions
. F

or ECT sensor tests,
REFER to Section 303
-14 Elec
tronic Engine
Controls. D

ifficult to start after hot soak
(vehicle standing after engine has
reached operating temperature)
Roc
hester valve
Thr

ottle contaminated
Purge

valve
Fue

l pump
Engine coolan

t temperature

(ECT) se
nsor
Blocked part-load breather
(s
ervice action S474)
Injec
t
or leak
Engine stalls
soon
after start
F
u
el pump relay
ECM relay Thr
o
ttle contaminated
CMP/CKP sen
s
or
synchronization malfunction
Harness Fuel
pump
MAF
s
ensor malfunction
Engine coolan
t
temperature
(ECT) sensor
Fue l
lines
Air leakage Fu

el pressure regulator
F
o
r fuel pump relay tests,
GO to Pinpoint Test E.
.
F or ECM
relay tests,
REFER to Section 303
-14 Elec tronic En
gine
Controls.
Check bull etins for throttl
e cleaning procedure. For

CMP/CKP sensor tests,
REFER to Section 303
-14 Elec tronic En
gine
Controls.
Chec k fu
el pressure,
REFER to Section 310
-00 Fu
el System
- Ge
n
eral
Informati
o
n
.
F or MAF sensor and
ECT sensor tests,
REFER to Section 303
-14 Electronic En
gine
Controls.
For fuel l
ine information,
REFER to Section 310
-01
Fuel Tank and Lines
.
F or i
ntake system information,
REFER to Section 303
-1 2
Intake Air Distribution
and F
ilt
ering
.
F o
r fuel pressure regulato
r check, GO to Pinpoint
Test D.
.
Engine h e
sitates/poor
acceleration
Fue l
pump
Exhaus
t gas
recirculation
(EGR)
Air leakage Stop lamp swi t
ch
Throttl
e
sensors
Throttl
e
motor
Spark plugs

fouled
Check f
o
r water ingress into
spark plug wells
Ignition coil fail
ure(s)
HT sho
rt to ground (tracking)
check rubber
boots for
cracks/damage
ECM failu r
e
Chec
k fu
el pressure,
REFER to Section 310
-00 Fu
el System
- Ge
n
eral
Informati
o
n
.
F o
r EGR information,
REFER to Section 303
-08 En gin
e Emission
Control.
F or i
ntake system information,
REFER to Section 303
-1 2
Intake Air Distribution
and F
ilt
ering
.
F or stop l
amp switch in
formation, refer to the
wiring diagrams. For throttle position sensor and throttle motor relay tests,
REFER to Section 303
-14 Elec tronic En
gine
Controls.
For ign i
tion system,
REFER to Section 303
-07 En
gine Ignition
.
Contact dealer techn i
cal
support for advice on
possible ECM failure.
Engine ba ckfiresFuel
pump
Air leakage MAF s
e
nsor
HO2 sensors Spark plugs
Check fo
r water ingress into
spark plug wells
HT short to ground (tracking) check rubber
boots for
cracks/damage
Ignition coil fail
ure(s)
Chec
k fu
el pressure,
REFER to Section 310
-00 Fu
el System
- Ge
n
eral
Informati
o
n
.
F or i
ntake system information,
REFER to Section 303
-1 2
Intake Air Distribution
and F
ilt
ering
.
For MAF and HO2
sensor circuit tests,
REFER to Section 303
-14 Electronic En
gine
Controls.
For igni
tion system,
REFER to Section 303
-07 En
gine Ignition
.
Engine
s
urges
Air leakage Fue
l
pump
Stop lamp swi
t
ch
MAF s
e
nsor
Harness Throttl
e
sensors
Throttl
e
motor
Spark plugs
Check fo
r water ingress into
spark plug wells
HT sho rt to ground (tracking)
check rubber
boots for
cracks/damage
ECM failu r
e
F
or i
ntake system information,
REFER to Section 303
-1 2
Intake Air Distribution
and F
ilt
ering
.
Chec k fu
el pressure,
REFER to Section 310
-00 Fu
el System
- Gen
e
ral
Informati
o
n
.
F or stop l
amp switch in
formation, refer to the
wiring diagrams. For MAF se nsor, throttle position
sensor and throttle motor relay tests,
REFER to Section 303
-14 Elec tronic En
gine
Controls.
For ign i
tion system,
REFER to Section 303
-07 En
gine Ignition
.
Contact dealer techn i
cal
support for advice on
possible ECM failure.

Pinpoint Tests
P1316Mi
sfire excess emission (this DTC
will flag only when accompanied by an individual cylinder misfire DTC: P0300-P0308)
Re
fer to possible causes for P0300-P0308
R
e
fer to actions for P0300-P0308.
P1611Thr
o
ttle angle malfunction
TP sensor
ci
rcuit fault
APP sensor circuit faul
t Throttle
assembly failure
ECM failu
r
e
F
or TP and APP
sens
or circuit tests,
REFER to Section 303
-14 El
ectronic
Engine
C
ontrols
.
F o
r throttle assembly information,
refer to throttle body in this section.
Contact dealer technical support for advice on possible ECM failure.
P1612Throttl e
offset malfunction
TP sensor
ci
rcuit fault
APP sensor circuit faul
t Throttle
assembly failure
ECM failu
r
e
F
or TP and APP
sens
or circuit tests,
REFER to Section 303
-14 El
ectronic
Engine
C
ontrols
.
F o
r throttle assembly information,
refer to throttle body in this section.
Contact dealer technical support for advice on possible ECM failure.
P1646Fu
el pump 2 relay malfunction (this
DTC applies only to the
supercharger secondary fuel pump)
Fu
el pump 2 relay failure
Fu

el pump 2 relay to ECM circuit
fault
Fu
el pump 2 relay coil power
supply open circuit
ECM ground circuit faul t (relay coil

drive)
For fuel pump 2 r
elay circuit tests,
GO to Pinpoint Test C.
.
PI
NPOINT TEST A : DTC P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208; FUEL
INJECTOR CIRCUIT MALFUNCTION
• NOTE
: The DTC set will indicate which cylinder injector or circ
uit is faulty. Only in the event of multiple cylinder misfires
will it be necessary to chec k more than one injector or circuit, in which case, multiple DTCs will be set.
TES
T
CONDITIONS
D E
TAILS/RESULTS/ACTIONS
A1
: CH
ECK THE INJECTOR COIL RESISTANCE
Turn the ignition swi
t
ch to the OFF
position.
1
Disconne
ct the relevant injector electrical connector
, (IJ03 to IJ10, vehicles with AJ26 engine, PI07 to
PI14, vehicles with AJ27 engine).
2
Meas ure t
he resistance between the injector pins.
3
Is
t
he resistance between 12 and 16 ohms?
Yes GO to A2
.
No
INST
ALL a new injector.
REFER to Fuel Injector
- Ve hicles With
out: Supercharger

in this
section.
CLEAR the DTC. TEST the system for normal operation.
A2: CHECK
THE INJECTOR COIL INSULATION
Meas
ure t
he resistance between the inje
ctor pin 01 and the injector body.
1
Measure t
he resistance between the inje
ctor pin 02 and the injector body.
2
Are both re
sistances greater than 10 Mohms?
Yes GO to A3
.
No
INST
ALL a new injector. CLEAR the DTC. TE
ST the system for normal operation.
A3: CHECK THE INJECTOR
SUPPLY VOLTAGE
Turn the ignition swi
t
ch to the ON
position.
1
Disconne
ct the relevant injector electrical connector
, (IJ03 to IJ10, vehicles with AJ26 engine, PI07 to
PI14, vehicles with AJ27 engine).
2
Meas ure t
he voltage between the relevant injector harness electrical connector (IJ03 to IJ10, vehicles

with AJ26 engine, PI07 to PI 14, vehicles with AJ27 engine), pin 02 (BR) and GROUND.
3
Is the volt
age greater than 12 volts?
Yes GO to A4
.
No
R
EPAIR the circuit between the relevant injector harn
ess electrical connector, pin 02 and battery. This

• NO
TE: 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
Sy
m
ptom
Possib
l
e source
Acti
o
n
Engine
cranks, but does
not fire
Secu
rit
y system /Immobiliser
engaged
Harness Fue l
system
ECM fault

Contact deal er techni
cal support for
information on security system. Check fuel
system pressure,
REFER to: Fuel System Pressure Check
(310
-
00 Fuel System - Genera l Information, General
Procedures).
For ECM tests,
REFER to: Electronic Engine Controls
(303
-14
Electronic Engine Co ntrols, Diagnosis and
Testing).
Engine cranks and
fi
res, but will not
start
Fu
el pump relay
Fuel

pump
Cyl
i
nder compression loss
(short-term. Refer to bulletin; 303-52)
Engine coolan t
temperature
(ECT) sensor
Spark plugs fouled, gapp
ed
incorrectly
Ignition coil fail
ure(s)
Check f
o
r water ingress into
spark plug wells
HT sho rt to ground (tracking)
check rubber
boots for
cracks/damage
Fo
r fuel pump relay tests,
REFER to: Fuel Charging and Controls
(303
-04

Fuel Charging and Controls, Diagnosis and Testing).
Check fuel pressure,
REFER to: Fuel System Pressure Check
(310
-
00 Fuel System - Genera l Information, General
Procedures).
For compression loss, REFER to the technical service bulletins. For ECT sensor tests,
REFER to: Electronic Engine Controls
(303
-14
Electronic Engine Co ntrols, Diagnosis and
Testing).
For spark plug tests, GO to Pinpoint Test B.
.
For ign i
tion system tests, GO to Pinpoint Test
A.
.
Diff
icult to start cold
Batt
ery Fuel
pump
Cyl
i
nder compression loss
(short-term. Refer to bulletin; 303-52)
Spark plugs fouled, gapp
ed
incorrectly
F o
r battery information,
REFER to: Battery and Cables
(414
-01 Battery,

Mounting and Cables, Description and Operation).
Check fuel pressure.
REFER to: Fuel System Pressure Check
(310
-
00 Fuel System - Genera l Information, General
Procedures).
For compression loss, REFER to the technical service bulletins. For spark plug tests, GO to
Pinpoint Test B.
. For ig
nition system tests, GO
to Pinpoint Test A.
.
Diff
icult to start hot
Roc
h
ester valve
Injec
t
or leak
Purge
val
ve
Fue
l
pump
Engine coolan
t
temperature
(ECT) sensor
F or R
ochester
valve test,
REFER to: Electronic Engine Controls
(303
-14
Electronic Engine Co ntrols, Diagnosis and
Testing).
For injector leak test, REFER to technical
service bulletins. Check fuel pressure. For evaporative emissions components,
REFER to: Evaporative Emissions
(303
-13
Evaporative Emissions, Diagnosis and Testing).
For ECT sensor tests,
REFER to: Electronic Engine Controls
(303
-14
Electronic Engine Co ntrols, Diagnosis and
Testing).
D iff
icult to start after hot soak
(vehicle standing after engine has reached operating temperature)
Roc h
ester valve
Injec
t
or leak
Purge
val
ve
Fue
l
pump
Engine coolan
t
temperature
(ECT) sensor
F or R
ochester
valve test,
REFER to: Electronic Engine Controls
(303
-14
Electronic Engine Co ntrols, Diagnosis and
Testing).
For injector leak test, REFER to technical service bulletins. Check fuel pressure,
REFER to: Fuel System Pressure Check
(310
-
00 Fuel System - Genera l Information, General
Procedures).

F
or evaporative emissions components,
REFER to: Evaporative Emissions
(30
3-13
Evaporative Emissions, Diagnosis and Testing).
For ECT sensor tests,
REFER to: Electronic Engine Controls
(30
3-14
Electronic Engine Co ntrols, Diagnosis and
Testing).
Engine stalls
soon after start
F
uel pump relay
ECM relay


Harness damage Fue

l pump
Engine coolan

t temperature
(ECT) sensor
Fue
l lines
F

uel pressure regulator
Air leakage


Check f
or DTCS. For fuel pump and ECM relay
tests,
REFER to: Fuel Charging and Controls
(30
3-04

Fuel Charging and Controls, Diagnosis and Testing).
Check fuel pressure.
REFER to: Fuel System Pressure Check
(31
0-
00 Fuel System - Genera l Information, General
Procedures).
For ECT sensor tests,
REFER to: Electronic Engine Controls
(30
3-14
Electronic Engine Co ntrols, Diagnosis and
Testing).
For fuel line information,
REFER to: Fuel Tank and Lines
(31
0-01 Fuel
Tank and Lines, Description and Operation).
For fuel pressure regulator,
REFER to: Fuel Charging and Controls
(30
3-04

Fuel Charging and Controls, Diagnosis and Testing).
For intake system information,
REFER to: Intake Air Distribution and Filtering

(30
3-12 Intake Air Distribution and Filtering,
Description and Operation).
Engine hesi
tates/poor acceleration
Fue
l pump
Air leakage


F

uel pressure regulator
Fue

l lines
Harness damage Throttl

e sensors
Throttl

e motor
Spark

plugs fouled, gapped
incorrectly
Ignition coil
failure(s)
Check f

or water ingress into
spark plug wells
HT sho
rt to ground (tracking)
check rubber boots for cracks/damage
Exhaus
t gas recirculation (EGR)

(SC only)
Chec
k fuel pressure,
REFER to: Fuel System Pressure Check
(31
0-
00 Fuel System - Genera l Information, General
Procedures).
For intake system information,
REFER to: Intake Air Distribution and Filtering

(30
3-12 Intake Air Distribution and Filtering,
Description and Operation). For fuel pressure regulator,
REFER to: Fuel Charging and Controls
(30
3-04

Fuel Charging and Controls, Diagnosis and Testing).
For fuel lines information,
REFER to: Fuel Tank and Lines
(31
0-01 Fuel
Tank and Lines, Description and Operation).
For throttle position se nsor and throttle motor
relay tests,
REFER to: Electronic Engine Controls
(30
3-14
Electronic Engine Co ntrols, Diagnosis and
Testing).
For spark plug tests, GO to Pinpoint Test B.
.
For ign
ition system tests, GO to Pinpoint Test
A.
. F
or EGR information,
REFER to: Engine Emission Control
(30
3-08
Engine Emission Cont rol, Description and
Operation).
Engine ba
ckfires
Fue
l pump
Fue

l lines
Air leakage


Mass ai

r flow (MAF) sensor
Spark plugs


Check f

or water ingress into
spark plug wells
HT sho
rt to ground (tracking)
check rubber boots for cracks/damage
Chec
k fuel pressure,
REFER to: Fuel System Pressure Check
(31
0-
00 Fuel System - Genera l Information, General
Procedures).
For fuel pump and lines,
REFER to: Fuel Tank and Lines
(31
0-01 Fuel
Tank and Lines, Description and Operation).
For intake system,
REFER to: Intake Air Distribution and Filtering

(30
3-12 Intake Air Distribution and Filtering,
Description and Operation). For MAF sensor tests,