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Thermometer at center ventilation louver
Trouble Diagnosis for Abnormal PressureS6RW0D7214002
NOTE
Normal pressure values on high side and low side in following table are measured when the ambient
temperature is 30 °C. As normal pressure values on high side and low side vary depending on the
ambient temperature, be sure to perform following steps first when diagnosing troubles.
1. Measure the ambient temperature and using that value, read the normal value from the graph given
in Step 10 of “A/C System Performance Inspection”.
2. Put that value in place of the normal pressure in following table.
Condition Possible 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) unitRepair or replace.
Compressor malfunction 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 malfunction Check compressor.
Condition
Possible cause Correction Manifold gauge MPa (kgf/cm2) (psi)
Detail
Lo Hi
0.27 – 0.39
(2.7 – 3.9)
(38.8 – 56.0)1.13 – 1.56
(11.4 – 15.6)
(162.3 – 221.8)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.Replace expansion
valve.
Replace desiccant and
cap with filter.
Evacuate the A/C
system and recharge
with fresh refrigerant.
Normal:
0.27 – 0.39
(2.7 – 3.9)
(38.8 – 56.0)
↑ ↓
Abnormal:
Negative pressureNormal:
1.13 – 1.56
(11.4 – 15.6)
(162.3 – 221.8)
↑ ↓
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 desiccant and
cap with filter.
Evacuate A/C system
and recharge with
fresh refrigerant.
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A/C System Inspection at ECMS6RW0D7214003
When checking voltage at ECM terminals related to A/C system, refer to “Inspection of ECM and Its Circuits in Section
1A”.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.
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 condenser
cooling fan operation.Inspect and repair
condenser 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 desiccant and
cap with filter.
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 (kgf/cm
2) (psi)
Detail
Lo Hi
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A/C System Symptom DiagnosisS6RW0D7214004
Condition Possible cause Correction / Reference Item
No cool air comes out (A/
C compressor does not
operate)No refrigerantPerform recovery, evacuation and charge
referring to “Operation Procedure for
Refrigerant Charge”.
Fuse blownCheck related fuses, and then check for short
circuit to ground.
A/C switch faultyCheck A/C switch referring to “A/C Switch
Inspection”.
Blower speed selector faultyCheck blower speed selector referring to
“Blower Speed Selector Inspection in Section
7A”.
Evaporator temperature sensor faultyCheck evaporator temperature sensor
referring to “Evaporator Temperature Sensor
Inspection”.
A/C refrigerant pressure sensor faultyCheck A/C refrigerant pressure sensor
referring to “A/C Refrigerant Pressure Sensor
and Its Circuit Inspection”.
Wiring or grounding faultyRepair as necessary.
ECM faultyCheck ECM referring to “A/C System
Inspection at ECM”.
Magnet clutch faultyCheck magnet clutch referring to “Magnet
Clutch Inspection”.
Compressor drive belt loosened or
brokenAdjust or replace drive belt.
Compressor faultyCheck compressor.
Compressor relay faultyCheck compressor relay referring to “A/C
System Relay Inspection”.
BCM faultyCheck BCM referring to “Inspection of BCM
and Its Circuits in Section 10B”.
No cool air comes out
(radiator cooling fan
motor does not operate)Fuse blownCheck related fuses, and then check for short
circuit to ground.
Wiring or grounding faultyRepair as necessary.
Condenser cooling fan relay faultyCheck condenser cooling fan motor relay
referring to “A/C System Relay Inspection”.
Condenser cooling fan motor faultyCheck condenser cooling fan motor referring to
“Condenser Cooling Fan Inspection”.
ECM faultyCheck ECM referring to “A/C System
Inspection at ECM”.
No cool air comes out
(blower motor does not
operate)Fuse blownCheck related fuses, and then check for short
circuit to ground.
Blower motor relay faultyCheck blower motor relay referring to “Blower
Motor Relay Inspection in Section 7A”.
Blower motor resistor faultyCheck blower motor resistor referring to
“Blower Motor Resistor Inspection in Section
7A”.
Blower speed selector faultyCheck blower speed selector referring to
“Blower Speed Selector Inspection in Section
7A”.
Wiring or grounding faultyRepair as necessary.
Blower motor faultyCheck blower motor referring to “Blower Motor
Inspection in Section 7A”.
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Cool air does not come
out or insufficient cooling
(A/C compressor normal
operation)Insufficient or excessive charge of
refrigerantCheck the amount of refrigerant and system
for leaks.
Condenser cloggedCheck condenser referring to “Condenser
Assembly On-Vehicle Inspection”.
A/C evaporator clogged or frostedCheck A/C evaporator and evaporator
temperature sensor referring to “Evaporator
Inspection” and “Evaporator Temperature
Sensor Inspection”.
Evaporator temperature sensor faultyCheck evaporator temperature sensor
referring to “Evaporator Temperature Sensor
Inspection”.
Expansion valve faultyCheck expansion valve referring to “Expansion
Valve Inspection”.
Desiccant cloggedCheck desiccant and cap with filter.
Compressor drive belt loosened or
brokenAdjust or replace drive belt.
Magnet clutch faultyCheck magnet clutch referring to “Magnet
Clutch Inspection”.
Compressor faultyCheck compressor.
Air in A/C systemReplace condenser, and then perform
evacuation and charge referring to “Operation
Procedure for Refrigerant Charge”.
Air leaking from HVAC unit or air ductRepair as necessary.
Heater and ventilation system faultyCheck HVAC unit.
Blower motor faultyCheck blower motor referring to “Blower Motor
Inspection in Section 7A”.
Excessive compressor oil in A/C systemDrain excessive compressor oil from A/C
system circuit and compressor.
Cool air does not come
out only intermittentlyWiring connection faultyRepair as necessary.
Evaporator temperature sensor faultyCheck evaporator temperature sensor
referring to “Evaporator Temperature Sensor
Inspection”.
Expansion valve faultyCheck expansion valve referring to “Expansion
Valve Inspection”.
Excessive moisture in A/C systemReplace condenser, and then perform
evacuation and charge referring to “Operation
Procedure for Refrigerant Charge”.
Magnet clutch faultyCheck magnet clutch referring to “Magnet
Clutch Inspection”.
Excessive amount of refrigerantCheck the amount of refrigerant.
Cool air comes out only at
high speedCondenser cloggedCheck condenser referring to “Condenser
Assembly On-Vehicle Inspection”.
Insufficient charge of refrigerantCheck the amount of refrigerant and system
for leaks.
Air in A/C systemReplace condenser, and then perform
evacuation and charge referring to “Operation
Procedure for Refrigerant Charge”.
Compressor drive belt loosened or
brokenAdjust or replace drive belt.
Compressor faultyCheck compressor.
Cool air does not come
out only at high speedExcessive amount of refrigerantCheck the amount of refrigerant.
A/C evaporator frostedCheck A/C evaporator and evaporator
temperature sensor referring to “Evaporator
Inspection” and “Evaporator Temperature
Sensor Inspection”. Condition Possible cause Correction / Reference Item
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Abnormal Noise Symptom Diagnosis of A/C SystemS6RW0D7214005
Abnormal Noise from Compressor
Abnormal Noise from Magnetic ClutchInsufficient air flow of
cooled airA/C evaporator clogged or frostedCheck A/C evaporator and evaporator
temperature sensor referring to “Evaporator
Inspection” and “Evaporator Temperature
Sensor Inspection”.
Air leaking from HVAC unit or air ductRepair as necessary.
Blower motor faultyCheck blower motor referring to “Blower Motor
Inspection in Section 7A”.
Wiring or grounding faultyRepair 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
revolutionsInadequate clearance in scroll areaReplace compressor.
A loud noise is heard at a
certain rpm,
disproportionately to
engine revolutionLoose or faulty compressor drive beltAdjust drive belt tension or replace drive belt.
Loose compressor mounting boltsRetighten mounting bolts.
A loud rattle is heard at
low engine rpmLoose compressor clutch plate boltRetighten 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 operationWorn or damaged bearingsReplace magnet clutch assembly.
A chattering noise is
heard when compressor
is in operationFaulty magnet clutch clearance
(excessive clearance)Adjust magnet clutch clearance.
Worn magnet clutch friction surfaceReplace magnet clutch assembly.
Compressor oil leaked from shaft seal,
contaminating the friction surfaceReplace compressor body assembly.
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Abnormal Noise from Tubing
Abnormal Noise from Condenser Assembly
Abnormal Noise from Crankshaft Pulley
Abnormal Noise from Tension Pulley
Abnormal Noise from A/C Evaporator
Abnormal Noise from Blower MotorCondition Possible cause Correction / Reference Item
A droning noise is heard
from inside of the vehicle,
but not particularly
noticeable in engine
compartmentFaulty tubing clampsReposition clamps or increase the number of
clamps.
Resonance caused by pulsation from
variations in refrigerant pressureAttach a silencer to tubing, or modify its
position and length.
Condition Possible cause Correction / Reference Item
Considerable vibration in
condenser assemblyResonance from condenser assembly
bracket and bodyFirmly insert a silencer between condenser
assembly bracket and body.
Condition Possible cause Correction / Reference Item
A large rattling noise is
heard at idle or sudden
accelerationLoosen crankshaft pulley boltRetighten bolt.
Condition Possible cause Correction / Reference Item
Clattering noise is heard
from pulleyWorn or damaged bearingReplace tension pulley.
Pulley cranks upon
contactCracked or loose bracketReplace or retighten bracket.
Condition Possible cause Correction / Reference Item
Whistling sound is heard
from A/C evaporatorDepending on the combination of the
interior / exterior temperatures, engine
rpm and refrigerant pressure, the
refrigerant flowing out of the expansion
valve may, under certain conditions,
make a whistling soundAt times, slightly decreasing refrigerant volume
may stop this noise.
Inspect expansion valve and replace if faulty.
Condition Possible cause Correction / Reference Item
Blower motor emits a
chirping sound in
proportion to its speed of
rotationWorn or damaged motor brushes or
commutatorReplace blower motor.
Fluttering noise or large
droning noise is heard
from blower motorLeaves or other debris introduced from
fresh air inlet to blower motorRemove debris and make sure that the screen
at fresh air inlet is intact.
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Repair Instructions
Operation Procedure for Refrigerant ChargeS6RW0D7216001
WARNING!
• Your eyes should not be exposed to refrigerant (liquid).
Any liquid HFC-134a (R-134a) escaping by accident shows a temperature as low as approximately –
6 °C (21.2 °F) below freezing point. Should liquid HFC-134a (R-134a) is exposed to your eyes, it may
cause a serious injury. To protect your eyes from such accident, it is necessary to always wear
goggles. Should it occur that HFC-134a (R-134a) is exposed to your eyes, consult a doctor
immediately.
– Do not use your hand to rub the affected eye(s). Instead, use fresh cold water to splash it over the
affected area to gradually raise temperature of such area above freezing point.
– Obtain proper treatment as soon as possible from a doctor or eye specialist.
• Should the liquid refrigerant HFC-134a (R-134a) is exposed to your skin, the affected area should be
treated in the same manner as when skin is frostbitten or frozen.
• Do not handle refrigerant near any place where welding or steam cleaning is performed.
• Refrigerant should be kept in a cold and dark place. It should never be stored in any place where
temperature is high, e.g. where exposed to direct sun light, close to fire or inside vehicle (including
trunk room).
• Avoid breathing fume produced when HFC-134a (R-134a) is burned. Such fume may be hazardous to
your health.
Start evacuation.Start evacuation.
Stop evacuation.Stop evacuation.
15 minutes (above -100 kPa)15 minutes (above -100 kPa)
Wait 10 minutesWait 10 minutes
Check A/C system forCheck A/C system for
pressure tighteness.pressure tighteness.
Recharge A/C system withRecharge A/C system withrefrigerant.refrigerant.
Check A/C system for refrigerantCheck A/C system for refrigerantleaks and amount of refrigerantleaks and amount of refrigerantcharged.charged.
Performance testPerformance test
Inspect and repair connections.Inspect and repair connections.
If gauge showsIf gauge showsabnormal conditionsabnormal conditions
Recharge 430 20 g ofRecharge 430 20 g ofrefrigerant.refrigerant.
I5RW0A721011-01
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Recovery
When discharging refrigerant out of A/C system, always
recover it by using refrigerant recovery and recycling
equipment because discharging refrigerant HFC-134a
(R-134a) into atmosphere would cause adverse effect to
environments.
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 supplied from factory
is filled up with the following amount of oil.
: Compressor oil 99000–99015–00A
(MATSUSHITADENKI GU10)
Oil amount in compressor
75 + 10, – 0 cm3 (75 + 10, – 0 ml, 2.54 + 0.34, – 0
US.oz, 2.64 + 0.35, – 0 lmp.oz)
When replacing other parts
Replenish the following amount of oil to compressor.
Amount of compressor oil to be replenished
Evaporator: 15 cm3 (15 ml, 0.51 US.oz, 0.53 Imp.oz)
Condenser: 10 cm3 (10 ml, 0.34 US.oz, 0.35 Imp.oz)
Dryer: 10 cm3 (10 ml, 0.34 US.oz, 0.35 Imp.oz)
Hoses: 5 cm3 (5 ml, 0.17 US.oz, 0.18 Imp.oz) each
Pipes: 5 cm3 (5 ml, 0.17 US.oz, 0.18 Imp.oz) each
I7RW01721009-01
1
I7RW01721010-01
1. New compressor
2. Removed compressor
I2RH01720015-01