INSUFFICIENT COOLING
HAC-73
< SYMPTOM DIAGNOSIS >[MANUAL AIR CONDITIONER]
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INSUFFICIENT COOLING
Component Function CheckINFOID:0000000001547073
SYMPTOM: Insufficient cooling
INSPECTION FLOW
1.CONFIRM SYMPTOM BY PERFORMING OPERATIONAL CHECK - TEMPERATURE DECREASE
1. Turn temperature control dial counterclockwise to maximum cold position.
2. Check for cold air at discharge air outlets.
Can the symptom be duplicated?
YES >> GO TO 3.
NO >> GO TO 2.
2.CHECK FOR ANY SYMPTOMS
Perform a complete operational check for any symptoms. Refer to HAC-6, "
Operational Check".
Does another symptom exist?
YES >> Refer to HAC-5, "How to Perform Trouble Diagnosis For Quick and Accurate Repair".
NO >> System OK.
3.CHECK FOR SERVICE BULLETINS
Check for any service bulletins.
>> GO TO 4.
4.CHECK COMPRESSOR DRIVE BELT TENSION
Check compressor belt tension. Refer to EM-15, "
Checking" (HR16DE) or EM-142, "Checking Drive Belts"
(MR18DE), or EM-263, "Inspection and Adjustment" (K9K).
OK or NG
OK >> GO TO 5.
NG >> Adjust or replace compressor belt. Refer to EM-15, "
Checking" (HR16DE) or EM-142, "Checking
Drive Belts" (MR18DE), or EM-263, "Inspection and Adjustment" (K9K)
5.CHECK AIR MIX DOOR CABLE
Check and verify air mix door cable operation. Refer to XXXX AIR MIX DOOR CABLE ADJUST.
Does air mix door operate correctly?
YES >> GO TO 6.
NO >> Repair or replace as necessary.
6.CHECK COOLING FAN MOTOR OPERATION
Check and verify cooling fan motor for smooth operation. Refer to XX-XX, "*****".
Does cooling fan motor operate correctly?
YES >> GO TO 7.
NO >> Check cooling fan motor. Refer to XX-XX, "*****".
7.CHECK FOR EVAPORATOR FREEZE UP
Start engine and run A/C. Check for evaporator freeze up.
Does evaporator freeze up?
YES >> Perform performance test diagnoses. Refer to "PERFORMANCE TEST DIAGNOSIS".
NO >> GO TO 8.
8.CHECK REFRIGERANT PRESSURE
Check refrigerant pressure with manifold gauge connected. Refer to "Test Reading".
OK or NG
OK >> GO TO 9.
NG >> Perform performance test diagnoses. Refer to "PERFORMANCE TEST DIAGNOSIS".
HAC-74
< SYMPTOM DIAGNOSIS >[MANUAL AIR CONDITIONER]
INSUFFICIENT COOLING
9.CHECK AIR DUCTS
Check ducts for air leaks.
OK or NG
OK >> If the symptom still exists, perform a complete operational check. Refer to HAC-6, "Operational
Check". If other symptoms exist, refer to HAC-5, "How to Perform Trouble Diagnosis For Quick
and Accurate Repair".
NG >> Repair air leaks.
Performance Test DiagnosesINFOID:0000000001547074
PERFORMANCE TEST DIAGNOSIS
RJIA1601E
INSUFFICIENT COOLING
HAC-75
< SYMPTOM DIAGNOSIS >[MANUAL AIR CONDITIONER]
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Performance ChartINFOID:0000000001547075
PERFORMANCE CHART
Test Condition
*1 "PERFORMANCE CHART" *2 "Test Reading" *3 "TROUBLE DIAGNOSIS FOR UN-
USUAL PRESSURE "
*4
*1 XXXX REMOVAL OF COMPRES-
SOR*2 XXXX BLOWER MOTOR CIR. *3 XX-XX, "*****"
RJIA3107E
HAC-76
< SYMPTOM DIAGNOSIS >[MANUAL AIR CONDITIONER]
INSUFFICIENT COOLING
Testing must be performed as follows:
Test Reading
Recirculating-to-discharge Air Temperature Table
Ambient Air Temperature-to-operating Pressure Table
*1: With blower control dial in the "1" position
*2: With blower control dial in the "4" position.
Test ReadingINFOID:0000000001547076
Recirculating-to-discharge Air Temperature Table
Vehicle condition Indoors or in the shade (in a well-ventilated place)
Doors Closed
Door window Open
Hood Open
TEMP. Max. COLD
Mode control dial
(Ventilation) set
Intake door lever
(Recirculation) set
Blower speedMax. speed set
Engine speed Idle speed
Operate the air conditioning system for 10 minutes before taking measurements.
Inside air (Recirculating air) at blower assembly inlet
Discharge air temperature at center ventilator
°C (°F) Relative humidity
%Air temperature
°C (°F)
50 - 6020 (68) 7.2 - 9.1 (45 - 48)
25 (77) 11.4 - 13.8 (53 - 57)
30 (86) 15.5 - 18.4 (60 - 65)
35 (95) 20.3 - 23.7 (69 - 75)
60 - 7020 (68) 9.1 - 10.9 (48 - 52)
25 (77) 13.8 - 16.2 (57 - 61)
30 (86) 18.4 - 21.3 (65 - 70)
35 (95) 23.7 - 27.1 (75 - 81)
Ambient air
High-pressure (Discharge side)
kPa (bar, kg/cm
2 , psi)Low-pressure (Suction side)
kPa (bar, kg/cm2 , psi) Relative humidity
%Air temperature
°C (°F)
50 - 7020 (68)843 - 1,036 *1
(11.08 - 13.63, 8.6 - 10.6, 122 - 150)159.0 - 194.0
(1.59 - 1.94, 1.62 - 1.98, 23.1 - 28.1)
25 (77)1,094 - 1,338 *1
(10.94 - 13.38, 11.2 - 13.6, 159 - 194)196.3 - 240.0
(1.96 - 2.40, 2.00 - 2.45, 28.5 - 34.8)
30 (86)1,298 - 1,590 *1
(12.98 - 15.90, 13.2 - 16.2, 188 - 231)248.0 - 302.7
(2.48 - 3.03, 2.53 - 3.09, 36.0 - 43.9)
35 (95)1,383 - 1,688 *2
(13.83 - 16.88, 14.1 - 17.2, 201 - 245)308.8 - 377.4
(3.09 - 3.77, 3.15 - 3.85, 44.8 - 54.7)
40 (104)1,628 - 1,988 *2
(16.28 - 19.88, 16.6 - 20.3, 236 - 288)377.4 - 461.2
(3.77 - 4.61, 3.85 - 4.70, 54.7 - 66.8)
INSUFFICIENT COOLING
HAC-77
< SYMPTOM DIAGNOSIS >[MANUAL AIR CONDITIONER]
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Ambient Air Temperature-to-operating Pressure Table
*1: With blower control dial in the "1" position
*2: With blower control dial in the "4" position.
Trouble Diagnoses for Unusual PressureINFOID:0000000001547077
TROUBLE DIAGNOSIS FOR UNUSUAL PRESSURE
Whenever system’s high and/or low side pressure(s) is/are unusual, diagnose using a manifold gauge. The
marker above the gauge scale in the following tables indicates the standard (usual) pressure range. Since the
standard (usual) pressure, however, differs from vehicle to vehicle, refer to above table (Ambient air tempera-
ture-to-operating pressure table).
Both High- and Low-pressure Sides are Too High
Inside air (Recirculating air) at blower assembly inlet
Discharge air temperature at center ventilator
°C (°F) Relative humidity
%Air temperature
°C (°F)
50 - 6020 (68) 7.2 - 9.1 (45 - 48)
25 (77) 11.4 - 13.8 (53 - 57)
30 (86) 15.5 - 18.4 (60 - 65)
35 (95) 20.3 - 23.7 (69 - 75)
60 - 7020 (68) 9.1 - 10.9 (48 - 52)
25 (77) 13.8 - 16.2 (57 - 61)
30 (86) 18.4 - 21.3 (65 - 70)
35 (95) 23.7 - 27.1 (75 - 81)
Ambient air
High-pressure (Discharge side)
kPa (bar, kg/cm
2 , psi)Low-pressure (Suction side)
kPa (bar, kg/cm2 , psi) Relative humidity
%Air temperature
°C (°F)
50 - 7020 (68)843 - 1,036 *1
(11.08 - 13.63, 8.6 - 10.6, 122 - 150)159.0 - 194.0
(1.59 - 1.94, 1.62 - 1.98, 23.1 - 28.1)
25 (77)1,094 - 1,338 *1
(10.94 - 13.38, 11.2 - 13.6, 159 - 194)196.3 - 240.0
(1.96 - 2.40, 2.00 - 2.45, 28.5 - 34.8)
30 (86)1,298 - 1,590 *1
(12.98 - 15.90, 13.2 - 16.2, 188 - 231)248.0 - 302.7
(2.48 - 3.03, 2.53 - 3.09, 36.0 - 43.9)
35 (95)1,383 - 1,688 *2
(13.83 - 16.88, 14.1 - 17.2, 201 - 245)308.8 - 377.4
(3.09 - 3.77, 3.15 - 3.85, 44.8 - 54.7)
40 (104)1,628 - 1,988 *2
(16.28 - 19.88, 16.6 - 20.3, 236 - 288)377.4 - 461.2
(3.77 - 4.61, 3.85 - 4.70, 54.7 - 66.8)
HAC-78
< SYMPTOM DIAGNOSIS >[MANUAL AIR CONDITIONER]
INSUFFICIENT COOLING
High-pressure Side is Too High and Low-pressure Side is Too Low
High-pressure Side is Too Low and Low-pressure Side is Too High
Both High- and Low-pressure Sides are Too Low
Gauge indication Refrigerant cycle Probable cause Corrective action
Both high- and low-pressure
sides are too high.Pressure is reduced soon af-
ter water is splashed on con-
denser.Excessive refrigerant charge in refrig-
eration cycle.Reduce refrigerant until
specified pressure is ob-
tained.
Air suction by cooling fan is in-
sufficient.Insufficient condenser cooling perfor-
mance.
↓
1. Condenser fins are clogged.
2. Improper fan rotation of cooling
fan. Clean condenser.
Check and repair cooling
fan if necessary.
Low-pressure pipe is not
cold.
When compressor is
stopped high-pressure val-
ue quickly drops by approx-
imately 196 kPa (1.96 bar, 2
kg/cm
2 , 28 psi). It then de-
creases gradually thereaf-
ter.Poor heat exchange in condenser
(After compressor operation stops,
high-pressure decreases too slowly.).
↓
Air in refrigeration cycle.Evacuate repeatedly and
recharge system.
Engine tends to overheat. Engine cooling systems malfunction.Check and repair each en-
gine cooling system.
An area of the low-pressure
pipe is colder than areas
near the evaporator outlet.
Plates are sometimes cov-
ered with frost. Excessive liquid refrigerant on low-
pressure side.
Excessive refrigerant discharge
flow.
Expansion valve is open a little
compared with the specification.
↓
Improper expansion valve adjust-
ment.Replace expansion valve.
AC359A
Gauge indication Refrigerant cycle Probable cause Corrective action
High-pressure side is too high
and low-pressure side is too low.
Upper side of condenser and
high-pressure side are hot,
however, liquid tank is not so
hot.High-pressure tube or parts located
between compressor and condenser
are clogged or crushed. Check and repair or re-
place malfunctioning
parts.
Check oil for contami-
nation.
AC360A
Gauge indication Refrigerant cycle Probable cause Corrective action
High-pressure side is too low
and low-pressure side is too
high.High- and low-pressure sides
become equal soon after com-
pressor operation stops.Compressor pressure operation
is improper.
↓
Damaged inside compressor
packings.Replace compressor.
No temperature difference be-
tween high- and low-pressure
sides.Compressor pressure operation
is improper.
↓
Damaged inside compressor
packings.Replace compressor.
AC356A
INSUFFICIENT COOLING
HAC-79
< SYMPTOM DIAGNOSIS >[MANUAL AIR CONDITIONER]
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Low-pressure Side Becomes Negative
Gauge indication Refrigerant cycle Probable cause Corrective action
Both high- and low-pressure
sides are too low. There is a big temperature dif-
ference between liquid tank
outlet and inlet. Outlet tem-
perature is extremely low.
Liquid tank inlet and expan-
sion valve are frosted.Liquid tank inside is slightly
clogged. Replace liquid tank.
Check oil for contamination.
Temperature of expansion
valve inlet is extremely low as
compared with areas near liq-
uid tank.
Expansion valve inlet may be
frosted.
Temperature difference oc-
curs somewhere in high-pres-
sure side.High-pressure pipe located be-
tween liquid tank and expansion
valve is clogged. Check and repair malfunc-
tioning parts.
Check oil for contamination.
Expansion valve and liquid tank
are warm or only cool when
touched.Low refrigerant charge.
↓
Leaking fittings or componentsCheck refrigerant for leaks.
Refer to XXXX CHECKING OF
REFRIG LEAKS .
There is a big temperature dif-
ference between expansion
valve inlet and outlet while the
valve itself is frosted.Expansion valve closes a little
compared with the specification.
↓
1. Improper expansion valve
adjustment.
2. Malfunctioning expansion
valve.
3. Outlet and inlet may be
clogged. Remove foreign particles by
using compressed air.
Replace expansion valve.
Check oil for contamination.
An area of the low-pressure pipe
is colder than areas near the
evaporator outlet.Low-pressure pipe is clogged or
crushed. Check and repair malfunc-
tioning parts.
Check oil for contamination.
Air flow volume is not enough or
is too low.Evaporator is frozen. Check thermo control amp.
Refer to XXXX MAG
CLUTCH CIR..
Replace compressor.
Repair evaporator fins.
Replace evaporator.
Refer to XXXX BLOWER
MOTOR CIR. .
AC353A
Gauge indication Refrigerant cycle Probable cause Corrective action
Low-pressure side sometimes be-
comes negative. Air conditioning system does
not function and does not cy-
clically cool the compart-
ment air.
The system constantly func-
tions for a certain period of
time after compressor is
stopped and restarted.Refrigerant does not discharge
cyclically.
↓
Moisture is frozen at expan-
sion valve outlet and inlet.
↓
Water is mixed with refrigerant. Drain water from refrigerant
or replace refrigerant.
Replace liquid tank.
AC354A
HAC-80
< SYMPTOM DIAGNOSIS >[MANUAL AIR CONDITIONER]
INSUFFICIENT COOLING
Gauge indication Refrigerant cycle Probable cause Corrective action
Low-pressure side becomes nega-
tive.
Liquid tank or front/rear side of
expansion valve’s pipe is frost-
ed or dewed.High-pressure side is closed
and refrigerant does not flow.
↓
Expansion valve or liquid tank
is frosted.Leave the system at rest until
no frost is present. Start it
again to check whether or not
the malfunction is caused by
water or foreign particles.
If water is the cause, initially
cooling is okay. Then the wa-
ter freezes causing a block-
age. Drain water from
refrigerant or replace refrig-
erant.
If due to foreign particles, re-
move expansion valve and
remove the particles with dry
and compressed air (not
shop air).
If either of the above meth-
ods cannot correct the mal-
function, replace expansion
valve.
Replace liquid tank.
Check oil for contamination.
AC362A