1998 JAGUAR X308 fuel pressure

The ru nning loss
system has the following features :
a
normall
y open pressure control valve is fi
tted at the lefthand side of the tank.
two charcoal
canisters are connected in series to reduce th
e concentration of fuel in vapour vented to atmosphere.
a t
ank pressure sensor and canister close
valve are fitted to allow the on-board di agnostic facility to test for leaks in
the fuel and evaporative system.
The pressure control valve allows continuo us venting of vapour to the charcoal canisters during normal running but prevents
fuel entering the vent line duri ng refueling. Fuel vapour from the tank passes through the valve to the lefthand canister and
a third pipe connects the valve to the fill er neck. When refueling, the difference in pressure betw een the tank interior and
the open filler neck causes the valve to cl ose, shutting off the vapour vent line. Wh en the fuel cap is replaced, the pressures
are equalised and the pressure control valve opens the vent line to the canisters.
The canister close valve is a solenoid operated device controlled by the ECM. The valve is normally open and is closed only
during the leak test sequence.
The fuel pressure sensor is fitted to th e evaporative loss flange and provides a volt age to the ECM which is proportional to
Ite
m
Par
t
Number
De
scr
iption
1—Vapour outl
et rol
lover valve
2—Evaporative flan
ge assembly
3—Tank vapour outlet pipe
4—Breather pipe
5—Pressure control
valve
6—Vapour pipe to canister
7—Charcoal cani
sters
8—Cani
st
er close valve
9—Vent pi
pe ai
r filter
10—Canister purge ou
tlet pipe
11—Vapour pipe conn
ecting canisters
12—EVAP canister purge v
a
lve
13—Vacuu
m
control signal from induction elbow
14—EVAP pu
rge valve outlet to induction elbow

Running Loss Sys
tem

tank vapou
r pressure.
Canister purge operation is as described in Evaporative Emissions Control.
Evaporative Flange Assembly

The evaporative loss flange assembly is fitted to the top of the tank via a seal and locking ring. The assembly is removeable
complete with the fitted components.
The vapour vent / rollover valve and pressure sensor are a pu sh fit via sealing grommets. The fuel pump connector is push
fitted and crimped into a location tu be on the underside of the flange.
It
em
Par
t Number
De
scription
1—Vapour vent /

rollover protection valve
2—Pres

sure sensor
3—Fue

l pump connector
4—Evaporative loss flange locking rin

g

The system has the
following features :
o
n
-board refueling vapour recovery (ORVR) to reduce the fu
el vapour vented directly to atmosphere from the filler
nozzle when refueling.
two ch arcoal
canisters are connected in series to reduce th
e concentration of fuel in vapour vented to atmosphere.
a t
ank pressure sensor and canister close
valve are fitted to allow the on-board di agnostic facility to test for leaks in
the fuel and evaporative system.
The canister close valve is a solenoid operated device controlled by the ECM. The valve is normally open and is closed only
during the leak test sequence.
The fuel pressure sensor is fitted to th e evaporative loss flange and provides a volt age to the ECM which is proportional to
tank vapour pressure.
Op era
tion of ORVR System
The ORVR system enabl
e
s fuel vapour generated during re-fueling to be collected by
the charcoal canisters. During normal
running of the vehicle, the vapour is collected and purged in the same way as for non-ORVR systems.
Ite
m
Par
t
Number
De
scr
iption
1—Grade vent
valve outl
et
2—Vapour outl
et from fil
l level vent valve (FLVV)
3—F
L
VV pressure relief valve outlet pipe
4—N
a
rrow diameter fuel filler tube
5—Charcoal can
i
sters
6—Cani
st
er close valve
7—Vent pi
pe ai
r filter
8—Vapour pipe
conn
ecting canisters
9—Canister purge ou
tlet pipe
10—EVAP canister purge v a
lve (engine bay)
11—Vacuu
m
control signal from induction elbow
12—EVAP pu
rge valve outlet to induction elbow

Running Loss with On-board R
efuelin
g Vapour Recovery (ORVR) System

The OR
VR system features are :
N

arrow fuel filler pipe and tank check valve.
Fue

l level vent valve (FLVV) fitted to the evaporative flan
ge and consisting of a two stage shut-off valve with rollover
protection and a pressure relief valve.
Grade ven
t valve with rollover protection, fitted to the ev
aporative flange and with an outlet pipe connected to the
FLVV vapour outlet pipe.
Large bore vapour vent pipes.

The fuel filler pipe has a reduced diameter between the nozzle guide and the tank, providing a liquid seal when re-fueling
and preventing the fuel vapour venting directly to atmosphere. There is no breather tube fitted between the tank and the
filler nozzle. To prevent spit back when re-fueling, a check valv e is fitted at the lower end of the filler pipe inside the tank
(see Figure).
During re-fueling, the tank is vented to atmosphere via the fuel level vent valv e (FLVV), large bore vapour pipes and the
charcoal canisters. The FLVV incorp orates a float valve which is closed by the rising fuel level, creating a back pressure and
causing the fuel delivery to stop. In the closed position, the FLVV also sets the fuel level.
With the FLVV closed (tank full), any increase in pressure or overfilling is relieved by a separate rollover protected grade
vent valve. The outlet from this valve feeds into the main FLVV vapour outlet pipe, bypassing the closed FLVV.
When the fuel level is below full, the FLVV opens to allow unrestricted venting via the canisters.
A pressure relief valve is incorp orated into the FLVV assembly and has an outlet pipe to the filler nozzle,. If a blockage or
other restriction (eg, canister close valve failing in the closed position) occurs in the vapour vent system, the pressure reli ef
valve opens to allow venting to atmosphere via the filler nozzle guide and fuel filler cap.
Canister purge operation is as described in Evaporative Emissions Control.
Filler Tube and Check Valve

The fuel fil
ler cap is the same as
that used on non-ORVR systems.
The check valve assembly is a push fit into the end of the fuel filler tube and is accessible with the evaporative flange
removed. The valve has a light spring load ing and opens under the inflow of fuel.
ORVR Evaporative Loss Flange Assembly

The evaporative loss flange assembly is fitted to the top of the tank via a seal and locking ring arrangement identical to that
used for non-ORVR systems. The assembly is re moveable complete with the fitted components.
The fuel level vent valve (FLVV) is mounted in the ELF assembly via a bayonet fitting : it is turned approximately 90 °
clockwise to release. The grade vent valve and pressure sensor are push in fits via sealing gromme ts : note that, due to the
tight fit, removal of these components may require cutting the grommets. The fuel pump connector is push fitted and
crimped into a location tube on the underside of the flange.
It e
m
Par
t
Number
De
scr
iption
1—An
ti-s
urge valve
2—Pressure rel
i
ef pipe
3—Check v
a
lve
It
e
m
Par
t
Number
De
scr
iption
1—Fi
ll
level vent valve (FLVV) /
pressure relief valve assembly
2—Pres
sure
sensor
3—Grade vent
valve
4—Fue
l
pump connector
5—Lockin
g rin
g
6—Evaporative loss flange (ELF)
7—Seal
8—F
u
el pump link lead

Driver Info
rmation
•

NOTE: Use this table to identify DTCs associated with the me
ssage center display, then refer to the DTC index for possible
sources and actions.
• NOTE: A trip is an ignition OFF, 30 seconds delay, ignition ON cycle, plus a minimum coolant temperature increase of 22°
C (40°F) after which the coolant temperat ure should reach a minimum 71°C (160°F)
Diagnostic Trouble C
ode (DTC) index
Sy
m
ptom
Possib
l
e Source
Acti
o
n
D
i
fficulty in filling
R
e
striction in the vapor line between the fuel tank and the
carbon canister outlet/atmospheric port
Check f or free f
low of air.
F
u
el smell
Adaptat
i
ons incomplete
Cani
st
er purge valve inoperative
Carry
o
ut the adaptations
procedure,
REFER to Section 303
-14 Ele c
tronic Engine Controls
.
Chec k cani
ster purge valve
operation.
M e
ssage center display

(see below)
Fue l
filler cap missing/not
tightened after refuelling
Check fu
el filler cap condition
and fitment.
Warning Li
ght
Mess
age Defaul
t Mode
DT
C
RedCheck Engine (after two
trip
s)
ECM de
fa
ult (canister purge inhibited, adaptive fuel
metering inhibited)
P0442,
P0444, P0445,
P0447, P0448.
Re dCheck Engine (after two
trip
s)
No
neP04 52,
P0453.
Di
agno
stic
Trouble Code
De scr
iption
Possib
l
e Source
Acti
o
n
P0442Sy
st
em leak detected
F
u
el tank filler cap seal defective
Sy
ste
m leak (c
anister damage,
pipework damage)
Cani st
er close valve leaking
F
u
el tank leak
Chec
k fi
ller cap,
system pipework,
fuel tank,GO to Pinpoint Test A.
.
F o
r fuel tank information,
REFER to Section 310
-01 Fu
el Tank

and Lines.
P0444Canist
er purge valve circuit
open circuit
Cani st
er purge valve to ECM
drive circuit; open circuit, high
resistance
Cani st
er purge valve failure
F
or purge
valve circuit tests,GO to
Pinpoint Test B.
.
P0445Canist
er purge valve circuit
short circuit
Cani st
er purge valve to ECM
drive circuit; short circuit to ground
Canist
er purge valve failure
(stuck closed)
F or purge
valve circuit tests,GO to
Pinpoint Test B.
.
P0447Canist
er close valve (CCV)
circuit open circuit.
CCV power su pply ci
rcuit; open
circuit, short circuit
CCV to ECM drive circuit;
open
circuit, high resistance, short circuit to B+ voltage
CCV failure
Fo
r CCV circuit tests,GO to Pinpoint

Test C.
.
P0448Canist
er Close Valve (CCV)
circuit short circuit
Cani st
er close valve to ECM drive

circuit; short circuit to ground
Cani st
er close valve failure
F
o
r CCV circuit tests,GO to Pinpoint

Test C.
.
P0452 Fu
el tank Pressure (FTP)
sensor circuit; low voltage (low pressure)
FTP sen
sor disconnected
FTP sen

sor to ECM sense circuit;
open circuit, short circuit to ground
FTP sens
or to ECM power supply
circuit open circuit, short circuit to ground
FT
P sensor failure
For FT
P se
nsor circuit tests,GO to
Pinpoint Test D.
.
P0453Fu
el tank Pressure (FTP)
sensor circuit; high voltage
(high pressure)
FTP sen
sor to ECM signal ground
circuit open circuit
F T
P sensor to ECM wiring
(supply, sense, signal ground),
short circuit to each other
FTP sen
sor to ECM sense circuit
short circuit to B+ voltage
For FT P se
nsor circuit tests,GO to
Pinpoint Test D.
.
FT
P sensor failure
Sym
ptom Chart

"d
iagnostic drive cycles" above.
No GO to B2
.
B2: CHECK THE PURGE VALVE DR
IV
E CIRCUIT FOR SHORT TO GROUND
Re
connect the battery negative terminal.
1
Meas
ure t
he resistance between EM39, pin 02 (PN for vehicles with AJ26
engine, UY for vehicles with
AJ27 engine), and GROUND.
2
Is t
he resistance less than 10,000 ohms?
Yes REPAIR the short circuit. For addi tional information, refer to the wiring diagrams. CLEAR the DTC.
Carry out a full Evaporative system monitor drive cycle.
No INSTALL a new purge valve,
REFER to Evaporative Emission Canister Purge Valve
- in thi
s section.
CLEAR the DTC. Carry out a full Evaporative system monitor drive cycle. Recheck DTCs. For additional
information, see "diagnostic drive cycles" above. If the DTC is repeated, contact dealer technical
support for advice on possible ECM failure.
PI
NPOINT TEST C : P0447, P0448; CANISTER CLOSE VALVE CIRCUIT OPEN/SHORT CIRCUIT
TE
S
T
CONDITIONS
D E
TAILS/RESULTS/ACTIONS
C1
: CH
ECK THE CCV DRIVE CIRCUIT FOR HIGH RESISTANCE
Turn the ignition swi
t
ch to the
OFF position.
1
Disc
onnect the battery negative terminal.
Vehicles with AJ26 engine:
Disc onne
ct the ECM electrical connector, EM13
Di
sc
onnect the CCV electrical connector, CV01
Meas
ure t
he resistance between EM13, pi
n 04, (OK) and CV1, pin 02 (OK)
Vehicles with AJ27 engine:
Disc onne
ct the ECM electrical connector, EM80
Di
sc
onnect the CCV electrical connector, CV01
Meas
ure t
he resistance between EM80,
pin 02 (GU) and CV1, pin 02 (GU)
2
Is the res
istance greater than 5 ohms?
Yes REPAIR the high resistance circuit. For additional information, refer to the wiring diagrams. CLEAR the
DTC. Carry out a full Evaporative system monitor drive cycle. For additional information, see
"diagnostic drive cycles" above.
No GO to C2
.
C2: CH
ECK THE CCV DRIVE CIRCUI
T FOR SHORT CIRCUIT TO GROUND
Re
connect the battery negative terminal.
1
Meas
ure t
he resistance between CV01,
pin 02 (OK for vehicles with AJ26 engine, GU for vehicles with
AJ27 engine), and GROUND.
2
Is t
he resistance less than 10,000 ohms?
Yes REPAIR the short circuit. For addi tional information, refer to the wiring diagrams. CLEAR the DTC.
Carry out a full Evaporative system monitor drive cycle.
No INSTALL a new CCV. CLEAR the DTC. Carry out a fu ll Evaporative system monitor drive cycle.
Recheck DTCs. For additional inform ation, see "diagnostic drive cycles" above. If the DTC is repeated,
contact dealer technical support for advice on possible ECM failure.
P INPOINT TES
T D : P0452, P0453; FUEL TANK
PRESSURE (FTP) SENSOR LOW/HIGH VOLTAGE
TES
T
CONDITIONS
DE
TAILS/RESULTS/ACTIONS
D
1:
CHECK THE FTP SENSOR SENSE CIRCUIT FOR HIGH RESISTANCE
Turn the ignition swi
t
ch to the OFF
position.
1
Disc
onnect the battery negative terminal.
2

E
vaporative Emissions - Fuel
Tank Pressure Sensor
Re
moval and Installation
Remov

al
Installation

1.
Disc
onnect battery ground cable (IMPORTANT, see SRO
86.15.19 for further information).
2. WARNING: BEFORE PROCEEDING, IT IS ESSENTIAL THAT
THE WARNING NOTES GIVEN IN SECTION 100-00 (UNDER THE
HEADING 'SAFETY PRECAUTIONS') ARE READ AND
UNDERSTOOD.
Drain the fuel tank using a suitab le suction pump/tanker. If the
On-board Refueling Vapor Recove ry (ORVR) system is fitted,
refer to General Procedures Section 310-01.
3. R
emove the fuel tank; refe
r to operation 19.55.01.

4. R
emove pressure sensor fro
m evaporative loss flange.
1. Installation is th e reverse of the re moval procedure.