1998 JAGUAR X308 injector

Fue
l pump
Engine coolan

t temperature

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

tor leak
Emiss
ions
.
Check bull
etins for throttle cleaning procedure.
Check fuel pressure. For ECT sensor circuit tests,
GO to Pinpoint Test C.
. Refer to Servi
ce action
S474 for part-load breather procedure. For
injector leak test, Refer to technical service bulletin 303-39.
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) sensor
Blocked part-load breather (
service action S474)
Injec

tor leak
Engine cranks too
fa
st/slow
Batt
ery
Starter relay Harness Cyl

inder compression loss
(NA short term only. Refer to technical service bulletin; 303-39)
R
efer to service action
S491
F
or battery information,
REFER to Section 414
-0
1 Battery, Mounting and

Cables.
F
or starting system.
REFER to Section 303
-06 Sta
rting System
.
R
efer to technical servic
e bulletins and service
actions.
Engine

stalls
Engine st
alls soon after
start
F
uel pump relay
ECM relay Thr

ottle contaminated
CMP/CKP sen

sor
synchronization malfunction
Harness Fue
l pump
MAF

sensor malfunction
Engine coolan

t temperature

(ECT) sensor
Fue
l lines
Air leakage


F

uel pressure regulator
Check r
elay dates. Chec
k for DTCs. For fuel
pump relay tests,
REFER to Section 303
-0
4 Fuel Charging and
Controls.
F
or ECM relay tests, GO to Pinpoint Test
AD.
.
Check bull
etins for throttle cleaning procedure.
For CMP sensor circuit test s, GO to Pinpoint Test
C.
, for
CKP sensor circuit tests, GO to Pinpoint
Test N.
. Check fuel
pressure. For MAF sensor
circuit tests, GO to Pinpoint Test A.
. For EC
T
sensor tests, GO to Pinpoint Test C.
. F
or fuel
system,
REFER to Section 303
-0
4 Fuel Charging and
Controls.
and
REF
ER to Section 310
-0
1 Fuel Tank and Lines
. F

or intake system information,
REFER to Section 303
-1
2 Intake Air Distribution

and F
iltering
.
Engine

stalls on overrun
Thr
ottle contaminated
ECM relay F

uel pump relay
CMP/CKP sen

sor
synchronization malfunction
Check bull
etins for throttle cleaning procedure.
Check relay dates. For ECM relay tests, GO to Pinpoint Test AD.
. F
or fuel pump relay tests,

REFER to Section 303
-0
4 Fuel Charging and
Controls.
F
or CMP sensor circuit test
s, GO to Pinpoint Test
O.
, for
CKP sensor circuit tests, GO to Pinpoint
Test N.
.
E
ngine stalls at steady
speed, with or without cruise enabled
Thr
ottle contaminated
ECM relay F

uel pump relay
CMP/CKP sen

sor
synchronization malfunction
Harness Blocked part-load breather
(
service action S474)
Check bull
etins for throttle cleaning procedure.
Check relay dates. For EC M relay circuit tests,GO
to Pinpoint Test AD.
. F
or fuel pump relay circuit

tests,
REFER to Section 303
-0
4 Fuel Charging and
Controls.
F
or CMP sensor circuit test
s,GO to Pinpoint Test
O.
, for
CKP sensor circuit tests,GO to Pinpoint
Test N.
. Che
ck service actions.
Engine st

alls when
maneuvering
ECM relay F
uel pump relay
CMP/CKP sen

sor
synchronization malfunction
Check r
elay dates. For EC
M relay circuit tests,GO
to Pinpoint Test AD.
. F
or fuel pump relay circuit

tests,
REFER to Section 303
-0
4 Fuel Charging and
Controls.
F
or CMP sensor circuit test
s,GO to Pinpoint Test
O.
, for
CKP sensor circuit tests,GO to Pinpoint
Test N.
.

P0122Throttle
position (TP) sensor 1 low
voltage
TP se ns
or to ECM sensing circuit 1
(TP sensor pin 3) open circuit or
high resistance
TP sensor fail
ure
F
o
r TP sensor circ
uit tests,GO to
Pinpoint Test D.
, and GO
to Pinpoint
Test K.
.
P0123Throttl e
position (TP) sensor 1
high voltage
TP se ns
or to ECM sensing circuit 1
(TP sensor pin 3) short circuit to
high voltage
TP sensor fail
ure
F
o
r TP sensor circ
uit tests,GO to
Pinpoint Test D.
, and GO
to Pinpoint
Test K.
.
P0125En
gine coolant temperature (ECT)
sensor response (for closed loop
fuel control)
Low/contaminated coolant Therm o
stat failure
ECT se
ns
or to ECM sensing circuit
high resistance, open circuit or
short circuit to high voltage
Che c
k coolant level and condition.
Check thermostat function. For ECT
sensor circuit tests,GO to Pinpoint
Test C.
.
P0131Right -
hand H02S sense circuit low
voltage
H02 S
disconnected
H0
2S to
ECM wiring open circuit
H0
2S short ci
rcuit to ground
H0
2S fail
ure
F
or R
ight-hand HO2S circuit tests,GO
to Pinpoint Test E.
.
P0132Right-
hand H02S sense circuit
high voltage
H02 S
sensing circuit short circuit to
high voltage
H0 2S groun
d braided shield open
circuit
H0 2S fail
ure
F
or R
ight-hand HO2S circuit tests,GO
to Pinpoint Test E.
.
P0133Right-
hand H02S sense circuit
slow response
Engine m
isfire
H02
S
disconnected
H0
2S mechanical damage

H0
2S to
ECM wiring intermittent
open circuit
H02 S
sensing circuit short circuit to
high voltage
H02S short ci
rcuit to ground
H02S groun

d braided shield open
circuit
H0 2S heater circuit faul
t
Exhaus
t leak

Low e
x
haust temperature
Injector fl
ow parti
ally blocked
Catal
y
st efficiency decrease
H0
2S fail
ure
Chec
k for 'en
gine misfire detected'
DTCs. For HO2S circuit tests,GO to
Pinpoint Test E.
.G
O to Pinpoint Test
F.
. Check for exhaust leaks,
REF
ER to Section 309
-00
Ex
haust
Sy
ste
m
.
Chec k inje
ctors,
REFER to Section 303
-04 Fu
el
Charging and Cont

rols
.
P0135Right
-
hand H02S heater circuit
malfunction
H02 S
disconnected
H0
2S h
eater power supply open
circuit
H0 2S heater to ECM wi
ring short
circuit or open circuit
H0 2S heater fai
lure
F
o
r right-hand HO2S heater circuit
tests,GO to Pinpoint Test F.
.
P0137Right-
hand catalyst monitor
sensor sense circuit low voltage
Catal y
st monitor sensor
disconnected
Catal y
st monitor sensor to ECM
wiring open circuit
Catal y
st monitor sensor short
circuit to ground
Cat a
lyst monitor sensor failure
F
or ri
ght-hand catalyst monitor sensor

circuit tests,GO to Pinpoint Test G.
.
P0138Right -
hand catalyst monitor
sensor sense circuit high voltage
Catal y
st monitor sensor sensing
circuit short circuit to high voltage
Catalyst
monitor sensor ground
braided shield open circuit
Cata
lyst monitor sensor failure
F
or ri
ght-hand catalyst monitor sensor

circuit tests,GO to Pinpoint Test G.
.
P0140Right -
hand catalyst monitor
sensor sense circuit no activity
Catal y
st monitor sensor
disconnected
Catal y
st monitor sensor
mechanical damage
Catal y
st monitor sensor to ECM
wiring open circuit
Catal y
st monitor sensor sensing
circuit short circuit to high voltage
Cataly
st monitor sensor short
circuit to ground
Catalyst
monitor sensor ground
braided shield open circuit
F or ri
ght-hand catalyst monitor sensor

circuit tests, GO to Pinpoint Test G.
.
Check f o
r exhaust leaks,
REFER to Section 309
-00 Ex
haust
Sy
ste
m
.
Chec k inje
ctors,
REFER to Section 303
-04 Fu
el
Charging and Con
t
rols
.

Exhaus
t leak
Low e

xhaust temperature
Cat

alyst monitor sensor failure
P0151Le

ft-hand H02S sense circuit low
voltage
H02
S disconnected
H0

2S to ECM wiring open circuit
H0

2S short circuit to ground
H0

2S failure
F
or left-hand HO2S circuit tests, GO
to Pinpoint Test H.
.
P0152Le
ft-hand H02S sense circuit high
voltage
H02
S sensing circuit short circuit to
high voltage
H0
2S ground braided shield open
circuit
H0
2S failure
F
or left-hand HO2S circuit tests,GO to
Pinpoint Test H.
.
P0153Le
ft-hand H02S sense circuit slow
response
Engine
misfire
H02

S disconnected
H0

2S mechanical damage
H0

2S to ECM wiring intermittent
open circuit
H02
S sensing circuit short circuit to
high voltage
H0
2S short circuit to ground
H0

2S ground braided shield open
circuit
H0
2S heater circuit fault
Exhaus

t leak
Low e

xhaust temperature
Injector fl

ow partially blocked
Catal

yst efficiency decrease
H0

2S failure
Chec
k for 'engine misfire detected'
DTCs. For HO2S circ uit tests, GO to
Pinpoint Test H.
. Check for exhaust
leak
s,
REFER to Section 309
-00
Exhaust
Sy

stem
.
Chec
k injectors,
REFER to Section 303
-04
Fuel
Charging and Con

trols
.
P0155Left-hand H02S heater

circuit
malfunction
H02
S disconnected
H0

2S heater power supply open
circuit
H0
2S heater to ECM wiring short
circuit or open circuit
H0
2S heater failure
F
or left-hand HO2S heater circuit
tests,GO to Pinpoint Test I.
.
P0157Le
ft-hand catalyst monitor sensor
sense circuit low voltage
Catal
yst monitor sensor
disconnected
Catal
yst monitor sensor to ECM
wiring open circuit
Catal
yst monitor sensor short
circuit to ground
Cat
alyst monitor sensor failure
F
or left-hand catalyst monitor sensor
circuit tests,GO to Pinpoint Test J.
.
P0158Le
ft-hand catalyst monitor sensor
sense circuit high voltage
Catal
yst monitor sensor sensing
circuit short circuit to high voltage
Catalyst
monitor sensor ground
braided shield open circuit
Cat
alyst monitor sensor failure
F
or left-hand catalyst monitor sensor
circuit tests,GO to Pinpoint Test J.
.
P0160Le
ft-hand catalyst monitor sensor
sense circuit no activity
Catal
yst monitor sensor
disconnected
Catal
yst monitor sensor
mechanical damage
Catal
yst monitor sensor to ECM
wiring open circuit
Catal
yst monitor sensor sensing
circuit short circuit to high voltage
Catal
yst monitor sensor short
circuit to ground
Catalyst
monitor sensor ground
braided shield open circuit
Exhaus
t leak
Low e

xhaust temperature
Cat

alyst monitor sensor failure
F
or left-hand catalyst monitor sensor
circuit tests,GO to Pinpoint Test J.
.
Check f
or exhaust leaks,
REFER to Section 309
-00
Exhaust
Sy

stem
.
P0171Right

-hand cylinders combustion
too lean
Air
intake leak between MAF senso
r and th

rottle
F

uel filter system blockage
F

uel injector blockage
F

uel pressure regulator failure (low

fuel pressure)
Low f
uel pump output
Check ai
r intake system for leaks,
REFER to Section 303
-1
2 Intake Air
Distribu

tion and Filtering
.
Check the fuel fi
lter,
REFER to Section 310
-01
Fuel Tank
and Lines.
Chec
k the fuel injectors and fuel

H02S harness wiri
ng fault
E
x
haust leak (before catalyst)
ECM receivi
n
g incorrect signal from

one or more of the following
sensors - ECT, MAF, IAT, TP
pr essure regulator,
REF
ER to Section 303
-04
Fu
el
Charging and Con
t
rols
.
Chec k the
fuel pressure. Check the
exhaust system for leaks,
REFER to Section 309
-00 Ex
haust
Sy
ste
m
.
R e
fer to pinpoint tests for sensors
listed.
P0172Right -
hand cylinders combustion
too rich
Engine m
isfire
Bl
ocked air
filter
F
u
el system return blockage
Leak
i
ng fuel injector(s)
F
u
el pressure regulator failure
(high fuel pressure)
ECM receivi n
g incorrect signal from

one or more of the following
sensors - ECT, MAF, IAT, TP
Chec k for 'en
gine misfire detected'
DTCs. Check the air filter element,
REFER to Section 303
-1 2
Intake Air
Distribu
tion and Filterin
g
.
Chec k the
fuel lines,
REFER to Section 310
-01 Fu
el Tank
and Lines.
Chec k the
fuel injectors and fuel
pressure regulator,
REFER to Section 303
-04 Fu
el
Charging and Con
t
rols
.
R e
fer to pinpoint tests for sensors
listed.
P0174L e
ft-hand cylinders combustion
too lean
Air in
take leak between MAF senso
r and th
ro
ttle
F
u
el filter system blockage
F
u
el injector blockage
F
u
el pressure regulator failure (low

fuel pressure)
Low fu
el pump output
H0
2S harness wiri
ng fault
E
x
haust leak (before catalyst)
ECM receivi
n
g incorrect signal from

one or more of the following
sensors - ECT, MAF, IAT, TP
Check the ai r intak
e system for leaks,

REFER to Section 303
-1 2
Intake Air
Distribu
tion and Filterin
g
.
Check the fuel fi lter,
REF
ER to Section 310
-01
Fu
el Tank
and Lines.
Chec k the
fuel injectors and fuel
pressure regulator,
REFER to Section 303
-04 Fu
el
Charging and Con
t
rols
.
Chec k the
fuel pressure. For HO2S
circuit tests,GO to Pinpoint Test H.
,
a n
dGO to Pinpoint Test
I.
. Check
the
exhaust system for leaks,
REFER to Section 309
-00 Ex
haust
Sy
ste
m
.
R e
fer to pinpoint tests for sensors
listed.
P0175L e
ft-hand cylinders combustion
too rich
Engine m
isfire
Bl
ocked air
filter
F
u
el system return blockage
Leak
i
ng fuel injector(s)
F
u
el pressure regulator failure
(high fuel pressure)
ECM receivi n
g incorrect signal from

one or more of the following
sensors - ECT, MAF, IAT, TP
Chec k for 'en
gine misfire detected'
DTCs. Check air filter element,
REFER to Section 303
-1 2
Intake Air
Distribu
tion and Filterin
g
.
Chec k the
fuel lines,
REFER to Section 310
-01 Fu
el Tank
and Lines.
Chec k the
fuel injectors and fuel
pressure regulator,
REFER to Section 303
-04 Fu
el
Charging and Cont

rols
.
Re
fer to pinpoint tests for sensors
listed.
P0201 Fu
el injector circuit malfunction,
cyl 1
Injector discon n
ected
Inject
or wir
ing open or short circuit

Injector fail
ure
F
o
r fuel injector
circuit tests,
REFER to Section 303
-04 Fu
el
Charging and Con
t
rols
. P0202F
u
el injector circuit malfunction,
cyl 3
P0203F u
el injector circuit malfunction,
cyl 5
P0204F u
el injector circuit malfunction,
cyl 7
P0205F u
el injector circuit malfunction,
cyl 2
P0206F u
el injector circuit malfunction,
cyl 4
P0207F u
el injector circuit malfunction,
cyl 6
P0208F u
el injector circuit malfunction,

cyl 8
P0222Thro
ttle position (TP) sensor
circuit 2 low voltage
TP se
nsor to ECM sensing circuit 2
(TP sensor pin 2) open circuit or
high resistance
TP sensor
failure
F
or TP sensor circ
uit tests,GO to
Pinpoint Test D.
, andG
O to Pinpoint
Test K.
.
P0223Thro
ttle position (TP) sensor
circuit 2 high voltage
TP se
nsor to ECM sensing circuit 2
(TP sensor pin 2) short circuit to
battery voltage
TP sensor
failure
F
or TP sensor circ
uit tests,GO to
Pinpoint Test D.
, andG
O to Pinpoint
Test K.
.
P0300Ran
dom misfire detected
ECM to
ignition module primary
circuit faults (cylinder misfire
detected DTCs also logged)
Igni
tion module to ignition coil
primary circuit fault(s) (cylinder
misfire DTC also logged)
Ignition modu
le ground circuit;
open circuit, hi gh resistance
Ignition coil
failure(s)
Ignition modul

e failure(s)
Check f

or water ingress into spark
plug wells
HT sho
rt to ground (tracking)
check rubber boots for
cracks/damage
Spark plug
failure/fouled/incorrect
gap
Cy
linder compression low
F

uel injector circuit fault(s)
(injector DTCs also logged)
F
uel delivery pressure (low/high)
F

uel injectors restricted/leaking
Fuel contamination


P

AS pulley bolts loose (see Service
Action S462)
W
orn camshaft/broken valve
springs
F
or ignition circuit tests,
REFER to Section 303
-07
Engine
Ignition.
F
or engine information,
REFER to Section 303
-00
Engine
Sy

stem
- General
Information
.
F
or fuel system information,
REFER to Section 303
-04
Fuel
Charging and Con

trols
.
Check service
actions.
P0301Mis

fire detected, cyl 1
R
efer to possible sources for P0300
R
efer to actions for P0300.
P0302Mis

fire detected, cyl 3
P0303Mis

fire detected, cyl 5
P0304Mis

fire detected, cyl 7
P0305Mis

fire detected, cyl 2
P0306Mis

fire detected, cyl 4
P0307Mis

fire detected, cyl 6
P0308Mis

fire detected, cyl 8
P0327Right

-hand knock sensor (KS)
sense circuit out of range (low
voltage)
Poor sensor cont
act with cylinder
block
KS to
ECM sense circuit short
circuit to ground
KS fai
lure
F
or right-hand knock sensor circuit
tests,GO to Pinpoint Test L.
.
P0328Right
-hand knock sensor (KS)
sense circuit out of range (high
voltage)
Poor sensor cont
act with cylinder
block
KS to EC
M sense circuit high
resistance or open circuit
KS to
ECM sense circuit short
circuit to high voltage
KS fai
lure
F
or right-hand knock sensor circuit
tests,GO to Pinpoint Test L.
.
P0332Left-hand knock sens
or (KS) sense

circuit out of range (low voltage)
Poor sensor cont
act with cylinder
block
KS to
ECM sense circuit short
circuit to ground
KS fai
lure
F
or left-hand knoc
k sensor circuit
tests,GO to Pinpoint Test M.
.
P0333Left-hand knock sens
or (KS) sense

circuit out of range (high voltage)
Poor sensor cont
act with cylinder
block
KS to EC
M sense circuit high
resistance or open circuit
KS to
ECM sense circuit short
circuit to high voltage
F
or left-hand knoc
k sensor circuit
tests,GO to Pinpoint Test M.
.

The upstream heated oxygen sensor is located at the catalytic converter inlet and detects the concentration of oxygen in the
raw exhaust gases; an internal heater reduces the warm up time of the sensor output.
An oxygen sensor (without heater) is located at the converter outlet.
The ECM receives input signals from the se nsors and varies the fuel injector duration (mixture) to provide optimum gas
emissions.
Circuit Diagram, O2 Sensors / ECM

Fuel System - General Inform
ation - Fuel System
Description an
d Operation

The fuel tank is mounted across the vehicle behind the passenger compartment bulkhead.
Fuel is drawn by the fuel pump from the tank and then supplied to the two fuel rails, via a filter.
Fuel injectors are installed in the fuel ra ils on each side of the intake manifold.
The amount of fuel injected into th e engine is controlled by the ECM.
A cross-over pipe connects the two fuel ra ils together at the front of the manifold.
A test valve in the cross-over pipe allo ws the fuel rail to be pressurized and de-pressurized during the servicing and
troubleshooting procedures.
A pressure regulator on the rear of the right fuel rail controls the pressure in the fuel rails.
A return line directs excess fuel from the pressure regulator back to the fuel tank.
Operation and service procedures
The fuel injector
s, rails, pres
sure regulator and, wher e fitted, supercharger are described in greater detail in Section 303-04
together with servicing procedures.
The fuel tank, pump, fuel level senders and fuel lines are similarly covered in Section 310-01.

Filler Cap and P
ipe
The fuel
filler cap with bayonet-type fixi
ng is located beneath a remote-release sp ring-latched lid on the rear saddle panel
on the left-hand-side of the vehicle.
Fuel Pum
p
The fu
el pump(s) is energized by an ECM co
ntrolled relay. Fuel is drawn by this pu mp and supplied to the fuel injectors via
the fuel line, filter and fuel rails.
Servicing of the fuel pump re quires fuel tank removal.
Ev
aporative Loss Flange Assembly
The evaporative-loss flan
ge asse
mbly is mounted centrally on top of the tank. The flange assembly consists of a removeable
steel cap which mounts the evaporative emissions system vapor outlet valves and, if applicable, a pressure sensor. The
external electrical supply to th e fuel pump(s) is also made via a connector on the flange.
The flange assembly is fixed to the tank by a locking ring which is turned usin g special tool JD-174. A seal is fitted between
the flange assembly and the tank. Three di fferent flange assemblies are applicable according to the evaporative emission
system fitted to the vehicle. The fl ange size and fixing are identical fo r the three systems, as described.
Removal of the evaporative flange assembly is necessary to gain access to th e fuel pump(s) and other internal components.
To remove the evaporative fl ange assembly the fuel tank must first be removed.
The evaporative flange variant assemblies are described, together with service information, in Section 303-13.
Fuel R
eturn
Excess fuel
is directed back to
the fuel tank via a return line.
Fuel Pum
p Relay
The
fuel pump relay,
under control of the ECM, switches power to the fuel pump motor.
I
nertia Fuel Shutoff (IFS) Switch
The IF
S switch is located in the right-hand
side footwell behind the footboard carpet . When activated the switch isolates the
ignition system and fuel pump, releases any locked doors and disables unnecessary electrical systems. The system can be
reset by pressing down the flexible cover on the top of the switch.
• NOTE: The doors will not unlock if the IFS switch is tripped when the ignition switch is in position '0'.