Downloaded from www.Manualslib.com manuals search engine 7B-8 Air Conditioning System: Manual Type
Cool air does not come
out or insufficient cooling
(A/C system normal
operation)Insufficient or excessive charge of
refrigerant
Check the amount of refrigerant and system
for leaks.
Condenser clogged Check condenser referring to “Condenser
Assembly On-Vehicle Inspection”.
A/C evaporator clogged or frosted Check A/C evaporator and evaporator
thermistor (evaporator temperature sensor)
referring to “Evaporator Inspection” and
“Evaporator Thermistor (Evaporator
Temperature Sensor) Inspection”.
Evaporator thermistor (Evaporator
temperature sensor) faulty Check evaporator thermistor (Evaporator
temperature sensor) referring to “Evaporator
Thermistor (Evaporator Temperature Sensor)
Inspection”.
Expansion valve faulty Check expansion valve referring to “Expansion
Valve Inspection”.
Desiccant clogged Replace receiver/dryer.
Compressor drive belt loosened or
broken Adjust or replace drive belt.
Magnet clutch faulty Check magnet clutch referring to “Magnet
Clutch Inspection”.
Compressor faulty Check compressor.
Air in A/C system Replace receiver/dryer, and then perform
evacuation and charge referring to “Operation
Procedure for Refrigerant Charge”.
Air leaking from HVAC unit or air duct Repair as necessary.
Heater and ventilation system faulty Check HVAC unit.
Blower motor faulty Check blower motor referring to “Blower Motor
Inspection in Section 7A”.
Excessive compressor oil in A/C system Drain excessive compressor oil from A/C
system circuit and compressor.
Cool air does not come
out only intermittently Wiring connection faulty
Repair as necessary.
Expansion valve faulty Check expansion valve referring to “Expansion
Valve Inspection”.
Excessive moisture in A/C system Replace receiver/dryer, and then perform
evacuation and charge referring to “Operation
Procedure for Refrigerant Charge”.
Magnet clutch faulty Check magnet clutch referring to “Magnet
Clutch Inspection”.
Excessive amount of refrigerant Check the amount of refrigerant.
Cool air comes out only
when driving vehicle at
high speed Condenser clogged
Check condenser referring to “Condenser
Assembly On-Vehicle Inspection”.
Insufficient charge of refrigerant Check the amount of refrigerant and system
for leaks.
Air in A/C system Replace receiver/dryer, and then perform
evacuation and charge referring to “Operation
Procedure for Refrigerant Charge”.
Compressor drive belt loosened or
broken Adjust or replace drive belt.
Compressor faulty Check compressor.
Cool air does not come
out only when driving
vehicle at high speed Excessive amount of refrigerant
Check the amount of refrigerant.
A/C evaporator frosted Check A/C evaporator and evaporator
thermistor (evaporator temperature sensor)
referring to “Evaporator Inspection” and
“Evaporator Thermistor (Evaporator
Temperature Sensor) Inspection”.
Condition Possible cause Correction / Reference Item
Downloaded from www.Manualslib.com manuals search engine Air Conditioning System: Manual Type 7B-9
Abnormal Noise Symptom Diagnosis of A/C SystemS7RS0B7214002
Abnormal Noise from Compressor
Abnormal Noise from Magnetic Clutch
Abnormal Noise from Tubing
Abnormal Noise from Condenser Assembly
Abnormal Noise from Crankshaft PulleyInsufficient airflow of
cooled air
A/C evaporator clogged or frosted
Check A/C evaporator and evaporator
thermistor (evaporator temperature sensor)
referring to “Evaporator Inspection” and
“Evaporator Thermistor (Evaporator
Temperature Sensor) Inspection”.
Air leaking from HVAC unit or air duct Repair as necessary.
Blower motor faulty Check blower motor referring to “Blower Motor
Inspection in Section 7A”.
Wiring or grounding faulty Repair as necessary.
Condition Possible cause Correction / Reference Item
Condition
Possible cause Correction / Reference Item
During compressor
operation, a rumbling
noise is heard
proportional to engine
revolutions Inadequate clearance in scroll area
Replace compressor.
A loud noise is heard at a
certain rpm,
disproportionately to
engine revolution Loose or faulty compressor drive belt
Adjust drive belt tension or replace drive belt.
Loose compressor mounting bolts Retighten mounting bolts.
A loud rattle is heard at
low engine rpm Loose compressor clutch plate bolt
Retighten clutch plate bolt.
Replace compressor if it was operated in this
condition for a long time.
Condition Possible cause Correction / Reference Item
A rumbling noise is heard
when compressor is not
in operation Worn or damaged bearings
Replace magnet clutch assembly.
A chattering noise is
heard when compressor
is in operation Faulty magnet clutch clearance
(excessive clearance)
Adjust magnet clutch clearance.
Worn magnet clutch friction surface Replace magnet clutch assembly.
Compressor oil leaked from shaft seal,
contaminating the friction surface Replace compressor body assembly.
Condition
Possible cause Correction / Reference Item
A droning noise is heard
from inside of the vehicle,
but not particularly
noticeable in engine
compartment Faulty tubing clamps
Reposition clamps or increase the number of
clamps.
Resonance caused by pulsation from
variations in re frigerant pressure Attach a silencer to tubing, or modify its
position and length.
Condition
Possible cause Correction / Reference Item
Considerable vibration in
condenser assembly Resonance from condenser assembly
bracket and body Firmly insert a silenc
er between condenser
assembly bracket and body.
Condition Possible cause Correction / Reference Item
A large rattling noise is
heard at idle or sudden
acceleration Loosen crankshaft pulley bolt
Retighten bolt.
Downloaded from www.Manualslib.com manuals search engine Air Conditioning System: Manual Type 7B-11
5) Warm up engine to the normal operating temperature and keep it at the specified idle speed.
6) Turn A/C switch ON, set blower speed selector at maximum speed position, temperature selector at
maximum cold position, airflow selector at face
position, and air intake switch at recirculation
position. (Confirm that A/C compressor and
condenser fans are working.)
7) Wait for ten minutes to stabilize the A/C operation.
8) Open front windows, front doors and engine hood.
9) With about 20 mm (0.8 in.) of dry bulb thermometer
(1) put right in front of center ventilation louver and a
wet and dry bulb thermometer (2) near air inlet of
HVAC unit. 10) Check for each pressure of low side and high side if
it is within shaded range of graph. If each gauge
reading is out of specified pressure, correct defective
part referring to the following table.
NOTE
Pressure registered on gauge varies with
ambient temperature. Therefore, use the
graphs when determining if pressures are
normal or not.
Low side and high side pressure example,
Gauges should read as follows when ambient
temperature is 30 °C (86 °F)
Pressure on high pressure gauge (HI): 1590 –
1940 kPa (15.9 – 19.4 kg/cm2)
Pressure on low pressure gauge (LO): 270 – 430
kPa (2.7 – 4.3 kg/cm
2)
2
1
I4RS0B720004-01
[A]: Pressure of high pressure gauge
[B]: Pressure of low pressure gauge
[C]: Ambient temperature
[D]: Humidity [E]: Acceptable range
22
312.9 2200
0 1
2 3 30 70 30 70 %
4 5 6 7 8 9
10
11 12 13 14 15
16 17
18
19 21
298.7 2100
20
14.2 28.4 42.7 56.9 71.1 85.3 99.5
113.8 128.0 142.2
151.4
170.6
184.9 199.1
213.3 227.5
241.7
256.0
270.2
284.4
100 200 300 400 500 600 700 800 900
1000 1100 1200
1300
1400 1500 1600
1700 1800
1900
2000
25 30 35
77 86 95
psi kPa kg/cm
2
C
F
“A”
“B”
“C”
“D”
23
2300
327.1
[A]
[B]
[C][D][E]
[E]
I7RS0A721006-01
Downloaded from www.Manualslib.com manuals search engine 7B-12 Air Conditioning System: Manual Type
High pressure gauge
Low pressure gaugeCondition Possible cause Correction
Pressure is higher than
acceptable range
(“A” area) Refrigerant overcharged Recharge.
Expansion valve frozen or clogged Check expansion valve.
Clogged refrigerant passage of high pressure side Clean or replace.
Radiator cooling fan malfunction
(Insufficient cooling of condenser)
Check radiator cooling fan.
Dirty or bent condenser fins
(Insufficient cooling of condenser) Clean or repair.
Compressor malfunction (Insuffi cient oil etc.) Check compressor.
Engine overheat Check engine cooling system
referring to “Engin
e Cooling Symptom
Diagnosis in Section 1F”.
Pressure is lower than
acceptable range
(“B” area) Insufficient refrigerant
(Insufficient charge or leakage)
Check for leakage, repair if necessary
and recharge.
Expansion valve malfunction
(valve opens too wide) Check expansion valve.
Compressor malfunction
(Insufficient compression) Check compressor.
Condition Possible cause Correction
Pressure is higher than
acceptable range
(“C” area) Expansion valve malfunction
(valve opens too wide)
Check expansion valve.
Compressor malfunction
(Insufficient compression) Check compressor.
Pressure is lower than
acceptable range
(“D” area) Insufficient refrigerant
(Insufficient charge or leakage)
Check for leakage, repair if necessary
and recharge.
Expansion valve malfunction
(valve opens too narrow) Check expansion valve.
Clogged refrigerant passage (crashed pipe) Repair or replace.
Downloaded from www.Manualslib.com manuals search engine Air Conditioning System: Manual Type 7B-13
11) Check inlet port temperature-to-outlet port temperature relationship using the graph. For example, if temperature
near air inlet of HVAC unit is 30 °C (86 °F) and the one at air outlet of center ventilation louver is 17 °C (62.6 °F),
their crossing point is within acceptable range as shown in the graph. In this case, cooling performance is
satisfactory and proper.
12) If crossing point is out of acceptable range, diagnose trouble referring to the following table.
Thermometer at center duct
NOTE
If ambient temperature is approximately 30 °C (86 °F), it is possible to diagnose A/C system in detail
referring to the following table.
[A]: Temp at air outlet of center ventilation louver [C]: Humidity
[B]: Temp near air inlet of HVAC unit [D]: Acceptable range
ConditionPossible cause Correction
Crossing point is higher
than acceptable range
(“E” area) Insufficient or excessive charge of refrigerant Check refrigerant pressure.
Dirty or bent A/C evaporator fins
Clean or repair.
Air leakage from cooling (heater) unit or air duct Repair or replace.
Malfunctioning, switch over function of door in
cooling (heater) unit Repair or replace.
Compressor malfunct ion Check compressor.
Crossing point is lower
than acceptable range
(“F” area) Insufficient air volume from center duct
(Heater blower malfunction)
Check blower motor and fan.
Compressor malfunct ion Check compressor.
8 9
10 11 12 13 14
15 16 17 18 19
20
21
22
23
24
25 26
27
28
46.4 48.2 50.0 51.8 53.6 55.4 57.2 59.0 60.8 62.6 64.4
66.2 68.0
69.8
71.6
73.4
75.2
77.0
78.8 80.6
82.4
25 30 35
77 86 95
F C
C
F
“E”
“F”30 70 %
[A]
[B][C]
[D]
I7RS0A721007-01
Downloaded from www.Manualslib.com manuals search engine 7B-14 Air Conditioning System: Manual Type
ConditionPossible cause Correction
Manifold gauge MPa (kg/cm2) (psi)
Detail
Lo Hi
0.27 – 0.43
(2.7 – 4.3)
(38 – 61) 1.59 – 1.94
(15.9 – 19.4)
(226 – 276)
Normal condition — —
Negative pressure 0.5 – 0.6
(5 – 6)
(71.2 – 85.3) The low pressure side
reads a negative
pressure, and the high
pressure side reads an
extremely low pressure.
Presence of frost around
tubing to and from
receiver/dryer and
expansion valve. Dust particles or water
droplets are either
stuck or frozen inside
expansion valve,
preventing the
refrigerant from
flowing.Clean expansion
valve.
Replace it if it cannot
be cleaned.
Replace receiver/
dryer.
Evacuate the A/C
system and recharge
with fresh refrigerant.
Normal:
0.27 – 0.43
(2.7 – 4.3)
(38 – 61)
↑ ↓
Abnormal:
Negative pressure Normal:
1.59 – 1.94
(15.9 – 19.4)
(226 – 276)
↑
↓
Abnormal:
0.7 – 1.0
(7 – 10)
(100 – 142) During A/C operation, the
low pressure side
sometimes indicates
negative pressure, and
sometimes normal
pressure. Also high
pressure side reading
fluctuates between the
abnormal and normal
pressure.
Expansion valve is
frozen due to
moisture in the
system, and
temporarily shuts off
the refrigeration cycle.
Replace expansion
valve.
Replace receiver/
dryer.
Evacuate A/C system
and recharge with
fresh refrigerant.
0.05 – 0.15
(0.5 – 1.5)
(4.2 – 21.3) 0.7 – 1.0
(7 – 10)
(100 – 142) Both low and high
pressure sides indicate
low readings.
Output air is slightly cold.
Insufficient refrigerant
in system
(Refrigerant leaking).Using leak detector,
check for leaks and
repair as necessary.
Recharge refrigerant
to a specified amount.
If the pressure reading
is almost 0 when the
manifold gauges are
attached, check for
any leaks, repair
them, and evacuate
the system.
0.4 – 0.6
(4 – 6)
(56.9 – 85.3) Pressure on low pressure
side is high.
Pressure on high
pressure side is low.
Both pressure becoming
equal right after A/C is
turned OFF.
Internal leak in
compressor.
Inspect compressor
and repair or replace
as necessary.
Downloaded from www.Manualslib.com manuals search engine Air Conditioning System: Manual Type 7B-15
A/C System Inspection at ECMS7RS0B7214004
Voltage Check
When checking voltage at ECM connector terminals related to A/C system, refer to “DTC P2101: Throttle Actuator
Control Motor Circuit Range / Performance in Section 1A”.
0.40 – 0.45
(4.0 – 4.5)
(57 – 64)
2.0 – 2.5
(20 – 25)
(285 – 355) High pressure reading on
both low and high
pressure sides.
Overcharged A/C
system.
Adjust refrigerant to
specified amount.
Faulty condenser
cooling operation. Clean condenser.
Faulty radiator cooling
fan operation. Inspect and repair
radiator cooling fan.
High pressure reading on
both low and high
pressure sides.
Low pressure side tubing
is not cold when touched. Presence of air in A/C
system
(Improperly
evacuated).Replace receiver/
dryer.
Inspect quantity of
compressor oil and
presence of
contaminants in oil.
Evacuate system and
recharge with fresh
refrigerant.
0.45 – 0.55
(4.5 – 5.5)
(64 – 78) High pressure reading on
both low and high
pressure sides.
Large amount of frost or
dew on the low pressure
side tubing.Faulty expansion
valve.
Refrigerant flow is not
regulated properly.
Replace expansion
valve.
Condition
Possible cause Correction
Manifold gauge MPa (kg/cm
2) (psi)
Detail
Lo Hi
Downloaded from www.Manualslib.com manuals search engine Air Conditioning System: Manual Type 7B-17
NOTE
• After recovering refrigerant from system, the amount of removed compressor oil must be measured
for replenishing compressor oil.
• When handling recovery and recycling equipment, be sure to follow the instruction manual for the equipment.
Replenishing Compressor Oil
It is necessary to replenish specified amount of
compressor oil to compressor from compressor suction
side hole (1) before evacuating and charging refrigerant.
When charging refrigerant only
When charging refrigerant without replacing any
component, replenish the same amount of measured oil
when recovering refrigerant (if not measure, replenish 10
cm
3 (10 ml, 0.34 US. oz, 0.35 Imp. oz) oil).
When replacing compressor
CAUTION!
Be sure to use specified compressor oil or an
equivalent compressor oil.
Compressor oil is sealed in each new compressor by the
amount required for A/C system. Therefore, when using
a new compressor, drain the calculated amount of oil
from it. “C” = “A” – “B”
“C”: Amount of oil to be drained
“A”: Amount of oil in a new compressor
“B”: Amount of oil in removed compressor
NOTE
Compressor assembly su
pplied from factory
is filled up with the following amount of oil.
: Compressor oil 99000–99015–00A
(MATSUSHITADENKI GU10)
Oil amount in compressor
90 ± 5 cm3 (90 ± 5 ml, 3.04 ± 0.17 US. oz, 3.17 ± 0.18
Imp. oz)
I4RS0A720012-01
1
I4RS0B720007-01
1. New compressor 2. Removed compressor
I2RH01720015-01