1998 JAGUAR X308 valve

re
placed.
E

vacuating the System
This process, the removal
of un
wanted air and moisture, is crit ical to the correct operation of the air conditioning system.
Moisture in the system can be highly de structive and may cause internal blockages due to freezing; water suspended in the
lubricating oil will dama ge the compressor. Once the system has been dismantled, or the refrigerant charge recovered, all
traces of moisture must be removed before recharging.
Specific procedures will vary depending on the individual characteristics of the recovery / recycle / recharge equipment, and
must be carried out exactly in accordance with the manufacturer 's instructions. However, it is recommended that initially
only the high-side valve be opened at the start of the procedure. After a short time a small depression should be seen on
the low-side, at which point the low-side valve may be opened and the evacuation process completed. If a vacuum is not
registered on the low-side, it may indicate that the expansion valve is permanently closed or that the system is blocked.
This simple check may save time and effort when the system is recharged.

Climate Control System - General Informatio
n - Climate Control System
D
iagn
osis and Testing
I
n
troduction
It is very i
m
portant to positive
ly identify the area of concern before starting a rectification procedure. A little time spent with
your customer to identify the conditions under which a pr oblem occurs will be beneficial. See below for example:
Sym
ptom Chart
Re
lev
ant criteria are: Weather conditions,
ambient temperature, intermittent or cont inuous fault, airflow fault, temperature
control fault, distribution fault and air inlet problem.
Functio n
al Check
This
s
imple 'first line check' will allo
w you to ascertain whether the system is operating within its design parameters, withou t
recourse to PDU.
1. 1. With the engine at normal running temperature.
2. 2. Presss AUTO to display selected temperature and illuminate AUTO and A/C state lamps.
3. 3. Rotate FAN to increase or decrease lowe r speed, verify bar graph representation.
4. 4. Select A/C to toggle on or off. (T he compressor may be inhibited by the ECM should either the engine
temperature NOT be normal or the ambient be < 2° C).
5. 5. Select RECIRC , state lamp should be lit and the recirculation flaps open.
6. 6. Select distribution butt ons in turn, verify correct air distribution and relevant state lamp.
7. 7. Select DEFROST , check max fans and air to the windshield.
8. 8. Cycle TEMPERATURE to ' HI ' and ' LO ' to verify demanded variations and display operation. Note that extremes
will provide max heat or cold independent of in-car temperature.
9. 9. Select EXT to toggle between am bient and control temperatures.
10. 10. Select F (where fitted) and R - noting exterior mirror; verify timer and operation (glass may be warm to the
touch)
11. 11. Initiate system 'Self Test' to display stored faul ts should any of the above not perform as stated.
Sy
stem Symptoms
There
are five
basic symptoms associated
with air conditioning fault diagnosis.
The following conditions are not in order of priority.
Sy m
ptom
Possib
l
e Sources
Acti
o
n
N
o defrostN o
airflow to windshield
*
Check blower s and flaps
*
N o functi
on in defrost mode
*
Check A/CCM
*
Mo de s
election not available
*
Chec k
control panel communication
*
Ai rfl
ow OK but no heat
*
Check water pu
mp and valve
*

Sym
ptom #2
Sy
mptom #2
Sym

ptom #3
Sy
mptom #3
No
cooling
Compressor sei
zed
Compressor seal failure
Compressor valve or piston damage
*
*
*
R
enew compressor
*
Compressor cl
utch / circuit faulty
*
R
efer to PDU
*
D
rive belt slack / broken
*
Adjust or r
enew
*
B
lower motor / circuit faulty
Pressure switch / circuit fault
*
*
R
efer to PDU
*
Total l
oss of refrigerant caused by broken pipe or joint
*
Repair / renew. Check code 2
3
*
P
artial loss of refrigerant caused by leaking joint or pipe
*
R
epair / renew, check fault code #23
*
Conden
ser damage
*
Re
new, check fault code #23
*
Bl
ocked receiver / drier filter
*
R
enew receiver / drier
*
Evaporator senso
r / circuit faulty
*
R
efer to PDU, check fault code #13
*
Bl
ocked pollen filter (if fitted)
*
Cle
an or renew
*
• NOTE: Should a leak or low refrigerant be established as the cause of INSUFFICIENT COOL ING, follow the procedures
Recovery / Recycle / Recharge, this section, and ob serve all refrigerant and oil handling instructions.
Sy
mptom
Possib
le Sources
Acti
on
Insuffi

cient
cooling
Compre
ssor clutch slipping
*
R
enew clutch assembly
*
Fl
aps or vents closed / seized
*
Check f
ault codes #41 to 46
*
Bl
ower circuit fault
*
R
efer to PDU
*
Bl
ocked condenser matrix / fins
*
Check hig
h / low side pr
essures / renew. Check /
clean fins
*
Bl
ocked evaporator matrix
*
Check hig
h / low side
pressures / renew
*
Bl
ocked pollen filter (if fitted)
*
Cle
an or renew
*
Evaporator temp
erat
ure sensor faulty
*
R
efer to PDU
*
P
artial loss of refrigerant caused by leaking joint

or pipe
*
R
epair / renew
*
Blocked expan
sion valve
*
Check hig
h / low side
pressures / renew
*
Expans
ion valve fault
*
Chec
k system pres
sure differential
*
C
ollapsed air conditioning hose hose
*
Check hig
h / low side
pressures / renew
*
Moi
sture or air in the system
*
Chec
k system pressures
*
Low r
efrigerant charge
*
Initiate recovery
procedure, check fault code #23
*
Coo
lant flow valve open
*
Chec
k operation
*
Sy
mptom
Possib
le Sources
Acti
on
Int

ermittent cooling
Compre
ssor clutch slipping
*
R
enew clutch assembly
*
Compressor cl
utch circuit faulty
Blower(s) circuit faulty
*
*
R
efer to PDU
*
Motorized in-car aspirator faulty

*
R
efer to PDU, check fault code #11
*
Evaporator temp
erature sensor faulty

*
R
efer to PDU, check fault code #13
*
Bl
ocked condenser matrix / fins
*
Check hig
h / low side pressures / renew. Check / clean fins

*
Bl
ocked evaporator matrix
*
Check hig
h / low side
pressures / renew
*


Sym
ptom #1
Sy
mptom #1
Sy

mptom
Possib
le Sources
Acti
on

Symp
tom #5
Sy
m
ptom #5


Low r
e
frigerant charge
*
Check f or 'hissi
ng' at expansion
valve; may be witnessed by low
HIGH side pressure. Recover / recharge
*
Moi
s
ture or air in the system
*
Chec k syst
em pressures
*
Heat er ci
rcuit air-lock
*
R e
fer section 303-03 for fill / bleed procedure
*
Suct ion
pipe touching bank 1 (A)
cylinder head (rubber isolator
missing)
*
Check the pi
pe cluster for correct fitti
ng
*
• NOTE: Electrical faults may be more rapidly traced using PDU
Sym
ptom
Possib
l
e Sources
Acti
o
n
Insuffi
ci
ent
heating
Coo l
ant flow valve stuck 'closed'
Coolant flow valve stuck 'open' allowing recirculation of
coolant at engine idle
*
*
Re
new v
alve
*
Motorized in-car aspirator sei zed
*R e
new aspirator
*
Coo l
air bypass damper stuck open

*
Re new,
check fault code #43

*
B l
ocked air inlet / pollen filter
*
Chec k / cl
ean / renew
*
B l
ower speed low
*
Check performance range
*
Low cool ant
level
*
Adjust as req u
ired (verify and correct
reason for loss)
*
Engine
t
hermostat faulty
*
Check engine r u
nning temperature
*
Heater water pump seized
*Chec k op
eration
*
Heater ma trix
blocked
*
Re new m
atrix
*
Heater circui t
air-lock
*
R e
fer section 303-03 for fill / bleed
procedure
*

Sym
p
tom #4
Sym
ptom #4
Sy
m
ptom
Possib
l
e Sources
Acti
o
n
No
i
sy
system
Loose or damaged compressor drive
belt
*Adjust or r
e
new
*
Loose compressor mountings
*Check f o
r damage, tighten to specification if OK
*
Compressor oil level l
ow
*
Look for evidence of l
eakag
e and rectify as required
*
Compressor internal dama ge
*Check f o
r debris, renew compressor and receiver drier
*
B l
ower motor noise
*
Re new m
otor (assuming no fan interference)
*
Excessive refrige rant charge
*Check f o
r vibration or 'thumping'
in high pressure line; may be
witnessed by high pressure on both HIGH and LOW sides.
Recover / recharge
*

Climate Co
ntrol System - General In
formation - Air Conditioning (A/C)
System Check - Re tail Procedure
Gen
eral Procedures
E

vacuating the Manifold Gauge Set
Connecting the Manifold Gauge Set
C
AUTION: Only use hoses with connectors wh
ich are dedicated to HFC 134A charge ports.
Stabilizing the System

1.
At
tach the center (service) hose to a vacuum pump and start
the pump. Open fully both high and low valves and allow the
vacuum to remove air and mois ture from the manifold set for
at least five minutes.
CAUTION: It is imperative th at the vacuum pump is not
subjected to a positi ve pressure of any degree. Therefore the
pump must be fitted wi th an isolation valve at the center (service
hose) connection and this valve mu st be closed before the pump
is switched off. This operation replaces the 'purge' procedure used
on previous systems. Observe the manufacturer's
recommendation with regard to vacuum pump oil changes.
Turn the vacuum pump off and isol ate it from the center service
hose but do not open the hose to atmosphere.
1. Att
achment of the hose quick release connectors to the high
and low side system ports is stra ightforward, provided that the
high and low valves are closed and the system is NOT
operational.
WARNING: UNDER NO CIRCUMSTANCES SHOULD THE
CONNECTIONS BE MADE WITH THE SYSTEM IN OPERATION OR
THE VALVES OPEN. SHOULD THE VALVES BE OPEN AND A
VACUUM PUMP OR REFRIGERANT CONTAINER ATTACHED, AN
EXPLOSION COULD OCCUR AS A RESULT OF HIGH PRESSURE
REFRIGERANT BEING FORCED BACK INTO THE VACUUM PUMP OR
CONTAINER.
Assessment of system operating efficiency and fault
classification may be achieved by using the facilities on your
Recovery / Recharging / Recycling station, follow the
manufacturer's instructions implicitly and observe all safety
considerations.
1. Accurate test gauge data wi
ll on
ly be attained if the system
temperatures and pressures are stabilized.
E
nsure that equipment and hoses cannot come into
contact with engine moving parts or sources of heat.
It is recommended th at a free standing air
mover is placed
in front of the vehicle to provide air flow through the
condenser / cooling system.
St
art the engine, allow it to attain normal working
temperature and set at fast idle (typically 1200 to 1500
rpm).


Select full

air condit
ioning performance.
With
all temperatures and pres
sures stable, or displaying
symptoms of faults; begin relevant test procedures.

Clima
te Control System - General Inform
ation - Manifold Gauge Set Connection
Ge
neral Procedures
Mani
fol
d.
Low Side Pressure Gauge.
High Side Pressure Gauge.

1.
The 'ma
nifold gauge set' is a most important tool for tracing faults and
system efficiency assessment. The relationship between HIGH and LOW
pressures and their correlation to AMBIENT and EVAPORATOR
temperatures must be compared to determine system status (see
Pressure / Temperature graphs).
Because of the heavy reliance upon this piece of equipment for service
diagnosis, ensure that the gauges are calibrated regularly and the
equipment is treated with care.

2.
Parts
List
ItemDescri
ption1LOW side
serv
ice hose

- BLUE
2LOW side
ha
nd valve -
BL
UE3LOW
pres
sure
compound
gauge _ BLUE
4HI GH

pressure
gauge _ RED
5HI GH
side
hand valve -
RED6HI GH
side
service hose
- RED
7Sys t
em
service hose
- Neutral color,
commonly YELLOW
1. The manifold is designed to control refrigerant flow. When connected into
the system, pressure is registered on both gauges at all times. During
system tests both the high and low side hand valves should be closed
(rotate clockwise to seat the valves). The hand valves isolate the low and
the high sides from the center (service) hose.
1. This compound gauge, is designed to register positive and negative
pressure and may be typically calibrate d - Full Scale Deflection, 0 to 10
bar (0 to 150 lbf / in2) pressure in a clockwise direction; 0 to 1000 mbar
(0 to 30 in Hg) FSD negative pressu re in a counter clockwise direction.
1. This pressure gauge may be typically calibrated from 0 to 30 bar (0 to
500 lbf / in2) FSD in a clockwise direction. Depending on the
manufacturer, this gauge may also be of the compound type.

Heating and Ventilation - Heating and Ventilation
Description and Operation
Schematic Diagram

Parts List
Heater System Components
ItemPart NumberDescription
1—Heater matrix
2—Firewall
3—Non return valve
4—Water pump
5—Water valve
6—Return to engine
7—Feed from engine
8—Non return valve (heater bypass)

Parts List
The heater circuit 'scavenges' coolant from the engine cooling system by mean s of an electric water pump. The water pump
has a protection circuit to inhibit operation when the coolant temperature is <16°C; this is to prevent possible damage to
the impeller due to the presence of coolant borne ice particles. Coolant is drawn from the en gine system through the water
valve inlet port into the heater matrix. The coolant passes thro ugh the bottom section of the heater matrix from left to right
filling the end tank of the matrix before returning through the top half of the ma trix and through the outlet ports of the
water valve and back into the engine cooling system.
Non return valves are located in the heat er bypass hose and the hose between the water pump and valve. These valves are
required to prevent coolant flowing in th e wrong direction at low engine speeds and restrict convected flow through the
heater after the engine is switched off.
When the exterior ambient temperature is > 0°C the refrigerat ion system automatically operates cooling and dehumidifying
incoming air before it is re -heated by the heater matrix.
Water Valve Assembly
Location
The water valve assembly is located above the water pump, in the engine compartmen t and is secured to the firewall by a
bracket. The valve operates by means of an electrical solenoid which oscillates the valve stem between the inlet and outlet
ports.
When in automatic mode, the water valve duty cycle is influenced by the following inputs to the A/CCM:
Outlet air temperature 'Air off' heater matrix temperature External ambient Coolant temperature
ItemPart NumberDescription
1—Assembly pump - water
2—Hose - from header tank
3—Hose / connector - return to engine
4—Hose - heater feed to matrix
5—Valve - non return (by-pass)
6—Hose / connector - feed from engine
7—Hose - heater return from matrix
8—Assembly valve - water
9—Valve - non return