Page 1753 of 2490

Climate Co
ntrol System - General In
formation - Climate Control System
Description an
d Operation
CAUTION: Observe all relevant safety requirements. Wear suitable eye and skin protection Do not mix HFC 134A and
CFC 12 refrigerants. Do not vent refrigerant directly to atmosphere and always use Jaguar approved recovery, recycle and
recharge equipment. Note the amount of recovered refrigerant; it will indicate the state of the system.
Working Practices
Be aware o
f, and comply with al
l health and safety requirements , whether they be legislative or common sense. This applies
to conditions set both for the operator and workshop.
Before commencing any repair or service procedure, disconnect the vehicle battery ground lead and protect the vehicle,
where appropriate, from dirt or damage.
Work in a well ventilated, clean and tidy area.
Keep all components and tools clean.
Recovery, recycle and recharge equipment must meet, or ex ceed, the requirements detailed in the Specification sub-
section.
Handling Refrigerant
We
ar eye protection at all times. Use gloves and keep all
skin covered that may come into contact with refrigerant.
Should refrigerant come into co ntact with eyes or skin, wash the affected area with cool water and seek medical advice; do
not attempt to treat the condition yourself.
Avoid breathing refrigerant vapor; it may cause irritation to the respiratory system.
CAUTION: Never use high pressure comp ressed air to flush out a system. Under certain ci rcumstances a combination
of HFC 134A refrigerant, compressed air and a source of combus tion (welding and brazing operations in the vicinity), may
result in an explosion and the release of potentially toxic compounds.
HFC 134A and CFC 12 refrigerants must neve r come into contact with each other. They will form an inseparable mixture
which can only be disposed of by incineration.
Do not vent refrigerant directly to atmo sphere; always use Jaguar approved recove ry equipment. Never depress the charge
or discharge port valves to check for the pr esence of refrigerant.
HFC 134A refrigerant is fully recycleable and it may be 'cleaned' by the recovery equipment and therefore re-used following
removal from a system.
Page 1754 of 2490

WARNING: NEVER USE A CFC 12 ANALYZ
ER OR NAKED FLAME TYPE.
Leak tests should be carried out with a UV spot lamp or an electronic analyzer which is dedicated to HFC 134A refrigerant.
Handling Lubricati
ng Oil
Av
oid breathing lubricant mist; it can cau
s
e irritation to the respiratory system.
Always use fresh oil from a sealed containe r and do not leave oil exposed to the atmosphere for any reason other than to fill
or empty a system. PAG oil is very hygr oscopic (absorbs water) and will rapidly become contaminated by atmospheric
moisture.
PAG oil is NOT compatible with previously used mineral based oi ls and must NEVER be mixed. Do not re-use oil when it has
been separated from refrigerant, following a re covery cycle. Dispose of used oil safely.
System Maintenance
Plug pipes an
d units immediatel
y after disconnection an d do not remove the plugs until immediately before making the
connection. Do not leave the system open to atmosphere.
The receiver drier must be renewed if the compressor has failed or if it is susp ected that debris may be present in the
system.
It is not always necessary to renew th e receiver drier if the correct procedur es have been followed. However, if a
component or part of the system is left dismantled for more than five minutes, it may be advisable to renew the receiver
drier. This guidance is based on UK average humidity levels; lo cations with lower humidity levels will be less critical to
moisture contamination. It must be stressed however th at there is not a safe period for work to be carried out in.
Do not use any replacement parts su pplied without transit plugs and seals - return them to the supplier.
Diagnostic equipment for pres sure, mass and volume should be calibrated regularly and certified by a third party
organization.
Use extreme care when handling and securi ng aluminum fittings; always use a backing spanner and take special care when
handling the evaporator.
Use only the correct or re commended tools for the job and apply the manufacturer's torque specifications.
Graph - High S
ide Pressure against Ambient Temperature
Page 1755 of 2490
The
'Normal' condition is that which is relevant to the prevailing ambient temperature.
Graph
- Low Side Pressure against Evaporator Temperature
(To obta
in lbf / in2 from bar,
multiply the figure by 14.5)
Page 1756 of 2490

Probable
causes of faults may be found by comparing actual
system pressures, registered on your manifold gauge set or
recovery / recharge / recycle station, and the relevant pressure to temperature relationship graph. The following chart
shows the interpretation that ma y be made by this difference.
• NOTE: The A/CCM will disengage the compressor clutch should the evaporator temperature fall to 0°C.
• NOTE: Graphs are typical for HFC 134A
The 'Normal' condition is that which is relevant to the prevailing evaporator temperature.
System Pressure Fault Classification
• NOTE
: If erratic or unusual gauge move
ments occur, check the equipment against a known (calibrated) manifold gauge
set.
This table should be used in conjunction with the graphical representations of 'High side' pressure / ambient temperature
and 'Low side' pressure / evaporator temperature.
Leak
Test
F
a
ults associated with low re
frigerant charge weight and low pressure ma y be caused by leakage. Leaks traced to
mechanical connections may be caused by to rque relaxation or joint face contamination. Evidence of oil around such areas
is an indicator of leakage.
Models that have fluorescent tracer dye incorporated into the refrigeration system can be checke d for non-apparent leaks by
scanning with a high intensity ultraviolet lamp. The location of leaks can be pinpointed by the bright yellow glow of the
tracer dye.
CAUTION: Observe ALL safety precautions associated with ultraviolet equipment.
Should a leak be traced to a joint, check that the fixing is secured to the correct tightening torque before taking any other
action.
When examining the system for leaks, chec k the compressor shaft seal and evaporator.
Charge Re
covery (system depressurization)
The process of
charge r
ecovery will depe
nd on the basic characteristics of your chosen recovery / recycle / recharge
equipment, therefore, follow the manu facturer's instructions carefully.
Remember that compressor oil may be drawn out during this process, take note of the quantity recovered so that it may be
Lo
w side
gauge reading
High s i
de
gauge reading
Fau l
t
Cause
No
r
mal
No
r
mal
Di
sc
harge air initially cool then
warms up
Mois
ture in system
N
ormal
to low
No
r
mal
As aboveAs above
LowLowD
i
scharge air slightly cool
Ref
r
igerant charge low
LowLowDi
scharge air warm
Refr
igerant charge very low
LowLowDi
scharge air slightly cool or frost
build up at expansion valve
Expansion valve st
uck closed
LowLowDi
scharge air slightly cool,
sweating or frost after point of restriction
Restri
ction in High side of system
HighLowCompressor noisyDe
fe
ctive compressor reed valve
HighHighD
i
scharge air warm and high side
pipes hot
Refri
gerant charge high or inefficient condenser
cooling due to air flow blockage or engine cooling fans
not working
HighHighD i
scharge air warm / Sweating or
frost at evaporator
Expans ion valve st
uck open
Page 1757 of 2490

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.
Page 1758 of 2490

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
*
Page 1759 of 2490

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
Page 1760 of 2490

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
*