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
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.
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
*
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.
Air
Particle Filter
The air particle filter system (where fitted) is located in the plenum below the windshield .
• NOTE: Refer to 'Filter Compensation', Section 412-04.
The filter elements are retained by adhesive strip which is atta ched to the filter moulding; the filter is fitted with the light,
flocked surface towards the engine.
Loca
tion of Air Distribution Ducts
LHD s
hown
Air Distribution and Filtering - Center Registers
Removal and Installation
Removal
Installation
1.
Remove battery cover and disconnect ground cable from battery
terminal. Refer to 86.15.19.
2. Remove passenger airbag deployment door for access. Refer to
Section 501-20.
3. Remove major gauge module veneer panel for access. Refer to
76.47.24.
4. Carefully withdraw fascia centre veneer panel.
5. Slacken and remove four screws securing centre vent assembly
to fascia.
6. Withdraw centre vent assembly for access, disconnect clock
harness multiplug, release clock retaining tangs and remove clock
from vent assembly.
7. Remove and discard the four veneer panel to fascia securing
clips.
1. Fit and fully seat new veneer panel retaining clips to fascia.
2. Fit clock to centre vent assemb ly, ensuring retaining tangs are
fully seated.
3. Position centre vent assembly at fascia and connect clock
harness multiplug.
4. Fully seat vent assembly in fascia and fit and tighten securing
screws.
5. Fit and fully seat centre veneer panel.
6. Fit major gauge module veneer panel. Refer to 76.47.24.
7. Fit passenger airbag deployment door. Refer to Section 501-20.
8. Connect ground cable to battery terminal and fit battery cover.
Refer to 86.15.15.
Ref #12 DEF (resumes the system on at the previous temperature setting).
Button (switch) logic
All buttons with an integral LED state lamp conform to the following operating logic.
When the state lamp is lit the relevant func tion is operational. From this condition, pressing the button will de-activate the
function, confirmed by the LED being de-energized and the pres ence of a single audible 'beep'. A single 'beep' will
accompany the state lamp to confirm function re-selection.
1. 1. ON / OFF and manual fan speed.
Pressing this knob activates the system ON at the last settin g or switches the system OFF. Rotate the knob clockwise to
increase and anti-clockwise to decrease fan speed and thus airflow.
With the system OFF, ram air is available by the selected air di stribution mode (indicated by state lamp). Air flow will NOT
occur unless a manual air distribution mo de is selected, this air being unconditioned and flow dependent upon vehicle
speed.
• NOTE: The blowers are inhibited until the engine coolant te mperature is > 35°C, unless DEFROST, FACE or DEMIST modes
are selected.
2. 2. Manual Air Recirculation
Closes the outside air intakes of the blower asse mblies and recirculates air within the vehicle.
Two options of control are available :
Timed Recirculation. Pressing the button for less than 1.5 seconds lights up the LED (confirmed by a single bleep).
This provides recirculation of interior air for a period of approximately 5 minutes. Pressing the button within five
minutes returns the system to fresh air intake mode.
Continuous Recirculation. Pressing and holding the button for more than 1.5 seconds lights up the LED (confirmed by two beeps). This provides continuous reci rculation of interior air. Pressing the button returns the system to fresh air
intake mode.
• NOTE: Avoid using manual air recirculatio n for prolonged periods in cold weather, this may result in interior misting of
glass.
3. 3. Temperature Scale Selection
Press the appropriate button to display temperatures in degrees Celsius or Fahrenheit.
4. 4. Manual Fan Speed
Rotating the fan speed control knob (to vary fan speed) will di splay a proportional number of horizontal bars on the LCD.
There are total of eleven manual fan speeds available.
5. 5. Temperature Display
Indicator of internal demand temperatur e or external ambient temperature. The external ambient is updated every 4
seconds when the road speed > 25 km / h.
6. 6. Scale
Selected temperature scale, Celsius or Fahrenheit.
7. 7. External temperature
Symbol indicates when this option is selected