fuel ratio JAGUAR X308 1998 2.G Service Manual

Pinpoint Tests
DT
C
De
scription
Possib
le Source
Acti
on
P1245Engine

crank signal low
voltage
Starter relay
coil to
ECM/BPM circuit open
circuit
F
or starter relay circuit tests,GO to
Pinpoint Test B.
.
P1246Engine
crank signal high
voltage
Starter relay
coil to ECM/BPM circuit short
circuit to B+ voltage
B
PM failure
F
or starter relay circuit tests,GO to
Pinpoint Test B.
.
P
INPOINT TEST A : CHECK THE
POWER SUPPLY, GROUND AND TRI GGER TO THE STARTER CIRCUIT
•
NOTE: During cranking with the engine disabled, observe the engine cranking speed. A cranking speed as low as 90 rpm
is acceptable, but will be difficult to measure. A degree of discretion must be used as to when an engine is cranking too
slowly.
TE
ST
CONDITIONS
D
ETAILS/RESULTS/ACTIONS
A1: CHECK

THE VOLT DROP AC
ROSS THE STARTER CIRCUIT
M
easure the volt drop across the circuit between the battery positive terminal and the starter motor
terminal, ST01.
1
Is the vol
t drop greater than 1 volt?
Yes CHECK the battery connections, cable connections at false bulkhead stud connector, and starter
motor. Make sure all connections are in good co ndition and secure. If all connections are sound,
INSTALL a new battery lead.
REFER to Section 414
-0
1 Battery, Mounting and Cables
.
TEST the system
for normal operation.
No GO to A2
.
A2: CHECK
THE VOLT DROP ACROSS
THE STARTER CIRCUIT (CRANKING)
Di
sable the fuel or ignition system to prevent the engine starting.
1

Turn the ignition swi
tch to the CRANK
position.
2
M
easure the volt drop across the circuit between the battery positive terminal and the starter motor
terminal, ST01.
3
Is the vol
t drop greater than 1 volt?
Yes CHECK the battery connections, cable connections at false bulkhead stud connector, and starter
motor. Make sure all connections are in good co ndition and secure. If all connections are sound,
INSTALL a new battery lead.
REFER to Section 414
-0
1 Battery, Mounting and Cables
.
TEST the system
for normal operation.
No GO to A3
.
A3:
CHECK THE GROUND TO THE STARTER MOTOR
Meas

ure the resistance between the engine GROUND lead and the starter motor body.
1

Is th
e resistance greater than 5 ohms?
Yes CLEAN the connection between the starter motor body and it's fittings, recheck the resistance. TEST
the system for normal operation.
No GO to A4
.
A4
: CHECK THE STARTER SIGNAL FROM THE STARTER RELAY
R

emove the fuel pump relay.
1

Di
sconnect the starter motor signal
electrical connector, ST03 (WR).
2
Turn the ignition swi
tch to the CRANK
position.
3
M
easure the voltage between ST03 (WR) and GROUND.
4

Is th
e voltage less than 10 volts?
Yes GO to A5
.
No

INSTALL a new starter motor.
REFER to Starter Motor
-

in t
his section.
TEST the system for normal operation.
A5
: CHECK THE STARTER SIGNAL CIRCUIT FOR HIGH RESISTANCE
R

emove the starter relay.
1

Meas

ure the resistance between the st
arter relay base, pin 05 and ST03 (WR).
2
Diagnostic Trouble Code (D
TC) Index

• 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,

Driver Information
Chart
•

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.
REF E
R 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.
.
Engine s
urges
Air leakage
Fue
l
pump
Fue
l
lines
Mass ai
r fl
ow (MAF) sensor
Harness damage Throttl
e
sensors
Throttl
e
motor
Spark plugs
Check fo
r water ingress into
spark plug wells
HT short to ground (tracking) check rubber
boots for
cracks/damage
Fo r
intake system,
REFER to: Intake Air Distribution and Filtering

(30 3
-12 Intake Air Distribution and Filtering,
Description and Operation). Check fuel pressure,
REFER to: Fuel System Pressure Check
(310
-
00 Fuel System - Genera l Information, General
Procedures).
For fuel pump and lines,
REFER to: Fuel Tank and Lines
(310
-01 Fuel
Tank and Lines, Description and Operation).
For MAF sensor, throttle position sensor and
throttle motor relay 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.
.
Engine detonates/k
nocks
Fue
l
lines
F
u
el pressure regulator
Air leakage
Mass air fl
ow (MAF) sensor
O
xygen senso
rs
Fue
l
pump
F
o
r fuel lines,
REFER to: Fuel Tank and Lines
(310
-01 Fuel
Tank and Lines, Description and Operation).
For fuel pressure regulator,
REFER to: Fuel Charging and Controls
(303
-04

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

(30 3
-12 Intake Air Distribution and Filtering,
Description and Operation).
For MAF sensor and oxyg en sensor tests,
REFER to: Electronic Engine Controls
(303
-14
Electronic Engine Co ntrols, Diagnosis and
Testing).
Check fuel pressure,
REFER to: Fuel System Pressure Check
(310
-
00 Fuel System - Genera l Information, General
Procedures).
No t
hrottle response
Throttl
e
sensors
Throttl
e
motor
Fo
r th
rottle position sensor tests, throttle
motor relay tests,
REFER to: Electronic Engine Controls
(303
-14
Electronic Engine Co ntrols, Diagnosis and
Testing).
Poor throttle responseThrottl e
sensors
Throttl
e
motor
Air leakage Mass air fl

ow (MAF) sensor
F
or throttl
e position se
nsor and throttle motor
relay tests,
REFER to: Electronic Engine Controls
(303
-14
Electronic Engine Co ntrols, Diagnosis and
Testing).
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,
REFER to: Electronic Engine Controls
(303
-14
Electronic Engine Co ntrols, Diagnosis and
Testing).

Default mode Definitions
MECHANIC
AL LIMP-HOME MODE:

No elec
tronic throttle operation (mechanical
operation for last quarter of pedal travel)
Ma
ximum 25° throttle opening,
depending on adjustment of th rottle mechanical linkage
Engine speed restri
cted to 3000
rpm maximum, by fuel cut-off
High i
dle speed (1200 rpm approx.)
Misfire
at idle, due
to cylinder cut as a means of control
ling idle speed (the misfire will switch cylinders, as the
strategy varies th e cylinder cut)
Cruise (speed) contr o
l inhibited
REVERSE THROTTLE PROGRESSION ENABLED:
Elec
tronic throttle operation, limited to maximum 25°
Cruise (speed) contr
o
l inhibited
• NOTE: The throttle oper ation uses the same map as for reverse gear.
ENGINE SPEED LIMIT:
Engine runs
normally, up to 3000 rpm.
Engine
speed restri
cted to 3000 rp
m maximum, by fuel cut-off.
Cruise (speed) contr o
l inhibited
LIMP-HOME UNAVAILABLE:
Cruise (speed) contro
l inhibited
Re

verse throttle pr
ogression engaged at second occurrence of DTC flagging
AmberRestri
cted
Performance
Engine
Speed Limit (runs normally, limited to

3000 rpm)
P01 16,
P0117, P0118, P0125
Ambe
rRestri
cted
Performance
Engine
Speed Limit (runs normally, limited to

3000 rpm)
P01 01,
P0102, P0103, P0104
Ambe
rRestri
cted
Performance
Engine
Speed Limit (runs normally, limited to

3000 rpm)
P03 00,
P0301, P0302, P0303, P0304, P0305,

P0306, P0307, P0308, P1313, P1314
Ambe rRestri
cted
Performance
Engine
Speed Limit (runs normally, limited to

3000 rpm)
P03 27,
P0328, P0332, P0333, P1648
Ambe
rRestri
cted
Performance
R e
verse throttle pr
ogression enabled
P1474
AmberRestri
cted
Performance
Engine
Speed Limit (runs normally, limited to

3000 rpm)
P1230
Ambe rRestri
cted
Performance
Engine
Speed Limit (runs normally, limited to

3000 rpm)
P1671
Ambe rRestri
cted
Performance
Engine
Speed Limit (runs normally, limited to

3000 rpm)
P11 12,
P1113
Ambe
rRestri
cted
Performance
Gearbox defau l
t to 4th gear
P1601 (SC on
ly)
AmberRestri
cted
Performance
Gearbox defau l
t to 4th gear
P16
05 (
NA only)
Ambe
rRestri
cted
Performance
Gearbox defau l
t to 4th gear
P0702
Ambe
rRestri
cted
Performance
Gearbox defau l
t to 4th gear
P1795
Ambe
rRestri
cted
Performance
Gearbox defau l
t to 4th gear
P1796
Ambe
rRestri
cted
Performance
Gearbox defau l
t to 4th gear
P1797
Ambe
rRestri
cted
Performance
Gearbox defau l
t to 4th gear
P1605
Ambe
rNoneGearbox defau l
t to 4th gear
P0705 (SC on
ly)
AmberNoneGearbox defau l
t to 4th gear
P0706
Ambe
rNoneGearbox defau l
t to 4th gear
P1720

Diagnostic Trouble Code (D
TC) index
D
iagnostic Trouble Code (DTC) Index
DT

C
De
scription
Possib
le Source
Acti
on
P0300Ran

dom misfire detected
ECM t
o ignition coil primary circuit
faults (cylinder misfire detected
DTCs also logged)
Ignition coil
ground circuit; open
circuit, high resistance
F
uel injector circuit fault(s)
(injector DTCs also logged)
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
Spark plug
failure/fouled/incorrect
gap
Cy
linder compression low
F

uel delivery pressure (low/high)
F

uel injectors restricted/leaking
Fuel contamination


P

AS pulley bolts loose (see Service

Actions)
W
orn camshaft/broken valve
springs
For ign
ition system tests,GO
to Pinpoint Test A.
. For
inje
ctor circuit tests,
REFER to: Fuel Charging and
Controls (30
3-04 Fuel
Charging and Controls,
Description and Operation).
Check compressions. For
spark plug tests,GO to
Pinpoint Test B.
.
Check fuel
pressure,
REFER to: Fuel System
Pressure Check (31
0-00 Fuel
System - General
Information, General
Procedures).
For fuel injectors,
REFER to: Fuel Charging and
Controls (30
3-04 Fuel
Charging and Controls,
Diagnosis and Testing).
For fuel tank and lines
information,
REFER to: Fuel Tank and
Lin
es

(310-01 Fuel Tank and
Lines, Description and
Operation).
Check PAS pulley bolt torque
(REFER to technical service
bulletins). For engine
information,
REFER to: Specifications

(3
03-01 Engine,
Specifications).
P0301Misfire
detected, Cyl 1
R
EFER to possible sources for P0300
R
EFER to actions for P0300.
P0302Misfire

detected, Cyl 3
P0303Misfire

detected, Cyl 5
P0304Misfire

detected, Cyl 7
P0305Misfire

detected, Cyl 2
P0306Misfire

detected, Cyl 4
P0307Misfire

detected, Cyl 6
P0308Misfire

detected, Cyl 8
P0351Igni

tion coil primary/secondary circuit
malfunction, cyl 1
ECM to
ignition module primary
circuit open circuit, short circuit to
ground, high resistance
Igni
tion module to ignition coil
primary circuit open circuit, short
circuit to ground, high resistance
Ignition modu
le ground circuit
open circuit, hi gh resistance
Ignition coil
failure
Ignition modul

e failure
F
or ignition circuit tests,GO to

Pinpoint Test A.
.
P0352Igni
tion coil primary/secondary circuit
malfunction, cyl 3
P0353Igni
tion coil primary/secondary circuit
malfunction, cyl 5
P0354Igni
tion coil primary/secondary circuit
malfunction, cyl 7
P0355Igni
tion coil primary/secondary circuit
malfunction, cyl 2
P0356Igni
tion coil primary/secondary circuit
malfunction, cyl 4
P0357Igni
tion coil primary/secondary circuit
malfunction, cyl 6
P0358Igni
tion coil primary/secondary circuit
malfunction, cyl 8
P1313Misfire rate
catalyst damage, Right-hand
cylinders. NOTE. This DTC will flag only
when accompanied by a random or
individual cylinder misfire DTC; P0300,
R
efer to possible causes for P0300-P0308
R
efer to actions for P0300-
P0308.

Engine Emission
Control - Engine Emission Control
D
iagn
osis and Testing
I
n
spection and Verification
1.
1. Veri fy the customer concern.
2. 2. Vis
ually inspect for obvious signs of mechanical
or electrical damage, correct fitment, etc.
Vi
sual Inspection Chart
3.
3. Veri fy the foll
owing syst
ems are working correctly:
Air intake
system
Coo
ling system

Charging system
Fu
el charging system
Ignition sys
t
em
4. 4. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding
to the next step
5. 5. Where the Jaguar approved diagnostic sy stem is available, complete the S93 report before clearing any or all fault
codes from the vehicle.
• NOTE: If a DTC cannot be cleared, then there is a permanent fault present that flag s again as soon as it is cleared (the
exception to this is P1260, which will only clear following an ignition OFF/ON cycle after rectification).
6. 6. If the cause is not visually evident and the Jaguar approv ed diagnostic system is not available, use a fault code
reader to retrieve the fault codes be fore proceeding to the Diagnostic Trou ble Code (DTC) Index Chart, or the
Symptom Chart if no DTCs are set.
7. 7. Using the Jaguar approved diagnostic system where available, and a scan tool where not, check the freeze frame
data for information on the conditions applicable when the fault was flagged. The format of this will vary,
depending on the tool used, but can pr ovide information useful to the technician in diagnosing the fault.
CAUTION: 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
MechanicalElectrical
Engi
ne
oil level
Coo
ling system coolant level

Fue
l
level
Fuel contaminatio
n
/
grade/quality
Throttle body Poly
-ve
e belt
Engine breath
er
system
pipework/connections
EGR pipework
condition (cracking, etc)
F
u
ses
W
i
ring harness
E
l
ectrical connector(s)
Sens
o
r(s)
Engine
control module (E
CM)
Sy
m
ptom
(general)
S y
mptom (specific)
Possib
l
e source
Acti
o
n
Poor
dr iveabilityEngine h e
sitates/poor
acceleration
Fue l
pump
Air leakage F
u
el pressure regulator
Chec
k fu
el pressure,
REFER to Section 310
-00 Fu
el
Sy
ste
m
- General Informati
on.

Evaporative E
missions - Evaporative Emissions
Description an
d Operation

To reduce the emission of fuel vapour, th e fuel tank is vented to atmosphere through activated charcoal adsorption canister
(s) which collects the fuel droplets. The ch arcoal is periodically purged of fuel when the EVAP Canister Purge Valve opens
the vapour line between the canister(s) and the air intake induct ion elbow. This action allows manifold depression to draw
air through the canister atmospheric vent, taking up the deposited fuel from the charcoal adsorber and burning the resulting
fuel vapour in the engine.
The EVAP Canister Purge Valve is controlled by the engine management system ECM. Purging is carried out in accordance
with the engine management fu eling strategy (see below).
The fuel tank vapour outlet is via a removeable flange assemb ly on the top surface of the tank. The vapour storage canister
or canisters are fitted on the underside of the vehicle below the rear seats.
There are three variants of the evaporativ e system. All systems use the charcoal adsorber storage canisters and purge valve
and operate as described above. The specific features of each system are described below. The evaporative systems are
designated as :
sin g
le canister system
ru
nn
ing loss system
ru
nn
ing loss with On-board Re-fueling Vapour Recovery (ORVR) system
EVAP Canister Purge Valve

Ite
m
Par
t
Number
De
scr
iption
1—EVAP canister purge v
alve
2—Valve s
olenoid connector
3—Vapour outlet to indu
ction elbow
4—Vapour
inlet from canister(s)
5—Vacuum contro
l pi
pe from induction elbow
6—Vacuum contro
l pi
pe to vapour pressure control va
lve - applicable to single canister systems only
7—Vacuum
control connection to EVAP valve

The E
VAP canister purge valve controls th
e flow rate of fuel vapour drawn into the engine during the canister purge
operation. The valve is opened by a vacu um feed from the induction elbow : the vacu um feed is controlled by the integral
valve solenoid and is applied when the so lenoid is energised. The solenoid is pulsed on (energised) and off by a fixed
frequency (100Hz) variable pulse width control signal (pulse width modulation). By varying the pulse on to off time, the
ECM controls the duty cycle of the valve (time that the valve is open to time closed) and thus the vapour flow rate to the
engine.
With no ECM signal applied to the va lve solenoid, the valve remains closed.
Can
ister Purge Operation
The
following pre-conditions are ne
cessary for purging to commence :
aft
er battery disconnection/reconnection, engine
management adaptations must be re-instated.
engine has run for
at least 8 seconds.
engi

ne coolant temperature is not less than 70 °C.
engine

not running in the fuel
cut off condition (eg overrun).
t
he adaptive fuel correction
function has not registered a rich or lean failure
t
he evaporative emission leak test has not failed
no faults have been diagnosted in th
e rel
evant sensor and valve circuits -
Air Flow Meter (AFM), Engine Coolant
Temperature sensor, Evaporativ e Canister Purge valve and Canister Close Valve (CCV).
If these conditions have been satisfied, purging is started. If any failures are registered, purging is inhibited.
The canister(s) is purged during each driv e cycle at various rates in accordance with the prevailing engine conditions. The
engine management software st ores a map of engine speed (RPM) against engine load (grams of air inducted / rev). For
any given engine speed and load, a vapour purge rate is assigned (purge rate increases with engine speed and load).
The preset purge rates are base d on the assumption of a vapour concentratio n of 100%. The actual amount of vapour is
measured by the closed loop fueling system : the input of evaporative fuel into the engine causes the outputs from the
upstream oxygen sensors to change, the am ount of change providing a measure of the vapour concentration. This feedback
causes the original purge rate to be adju sted and also reduces the amount of fuel input via the injectors to maintain the
correct air to fuel ratio.
Engine speed/load mapping and the corresp onding purge rates are different for single canister, running loss and ORVR
evaporative systems.

Thi s
system uses a single charcoal canister with a pressure
control valve between the canister and the fuel tank vapour
outlet. A vacuum control pipe is connecte d from the engine intake induction elbow to the pressure control valve. The vapour
outlet from the fuel tank is taken via a safety rollover valve fitted to the re moveable flange at the top of the tank.
With the engine stopped, the pressure control valve is closed, maintaining a slight positive pre ssure in the tank : any further
increase in pressure causes the valve to open and release vapour to the canister.
When the engine is running, manifold depr ession (via the vacuum control pipe) holds the pressure control valve open. Air is
drawn into the tank to maintain atmospheric pressure as fuel is used and vapourised fuel is deposited in the charcoal
canister.
Canister purge operation is as described in Evaporative Emissions Control.
It e
m
Par
t
Number
De
scr
iption
1—Evaporative flan
ge assembly
2—Vapour outlet rol
lover valve
3—Tank vapour outlet pipe
4—Breather
pipe
5—Pressure control valve
6—Induct
ion vacuum control pipe
7—Charcoal can
i
ster
8—Canister vapour outlet pipe
9—EVAP canister purge v
a
lve
10—Vacuu
m
control sign
al from induction
11—EVAP ca
nister purge valve outlet
12—Canist
er vent
to atmosphere
Single Ca
nister System