Page 481 of 3924
ATC-76
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
PERFORMANCE TEST DIAGNOSIS
*10AT C - 5 0 , "Operational Check"*11AT C - 4 , "Precaution for Working with
HFC-134a (R-134a)"
*12EM-14, "Checking Drive Belts"
(VQ35DE) or EM-170, "
Checking
Drive Belts" (VK45DE)
*13 EC-437, "
Description" (VQ35DE) or
EC-1030, "
Description" (VK45DE)
*1 "PERFORMANCE CHART" *2 "PERFORMANCE CHART" *3 "TROUBLE DIAGNOSIS FOR UN- USUAL PRESSURE"
*4 AT C - 5 9 , "
Air Mix Door Motor Circuit"
SJIA1226E
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TROUBLE DIAGNOSISATC-77
< SERVICE INFORMATION >
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PERFORMANCE CHART
Test Condition
Testing must be performed as follows:
*1 ATC-125, "Removal and Installation
of Compressor Clutch"
*2AT C - 6 4 , "Blower Motor Circuit"*3 EM-14, "Checking Drive Belts"
(VQ35DE) or EM-170, "
Checking
Drive Belts" (VK45DE)
SJIA1642E
Vehicle condition Indoors or in the shade (in a well-ventilated place)
Doors Closed
Door windows Open
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ATC-78
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
Test Reading
Recirculating-to-discharge Air Temperature Table
Ambient Air Temperature-to -operating Pressure Table
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
Hood Open
TEMP. Max. COLD
Mode switch (Ventilation) set
Intake switch (Recirculation) set
Fan (blower) speed Max. 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 - 60 20 (68) 11.2 - 13.2 (52 - 56)
25 (77) 12.2 - 14.8 (54 - 59)
30 (86) 15.5 - 18.6 (60 - 65)
35 (95) 21.0 - 24.5 (70 - 76)
40 (104) 28.7 - 32.6 (84 - 91)
60 - 70 20 (68) 13.2 - 15.2 (56 - 59)
25 (77) 14.8 - 17.3 (59 - 63)
30 (86) 18.6 - 21.6 (65 - 71)
35 (95) 24.5 - 28.0 (76 - 82)
40 (104) 32.6 - 36.5 (91 - 98)
Ambient air High-pressure (Discharge side)
kPa (kg/cm
2, psi) Low-pressure (Suction side)
kPa (kg/cm2, psi)
Relative humidity
% Air temperature
°C ( °F)
50 - 70 20 (68)
961 - 1,167
(9.8 - 11.9, 139 - 169) 216 - 265
(2.2 - 2.7, 31 - 38)
25 (77) 1,108 - 1,353
(11.3 - 13.8, 161 - 196) 230 - 281
(2.3 - 2.9, 33 - 41)
30 (86) 1,275 - 1,549
(13.0 - 15.8, 185 - 225) 261 - 320
(2.7 - 3.3, 38 - 46)
35 (95) 1,549 - 1,893
(15.8 - 19.3, 225 - 274) 297 - 364
(3.0 - 3.7, 43 - 53)
40 (104) 1,814 - 2,216
(18.5 - 22.6, 263 - 321) 357 - 435
(3.6 - 4.4, 52 - 63)
Vehicle condition Indoors or in the shade (in a well-ventilated place)
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TROUBLE DIAGNOSISATC-79
< SERVICE INFORMATION >
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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. The pressure returns to nor-
mal soon after water is
splashed on condenser.
Excessive refrigerant charge in
refrigeration cycle.
Reduce refrigerant until speci-
fied pressure is obtained.
Air suction by cooling fan is in-
sufficient. Insufficient condenser cooling
performance.
↓
1. Condenser fins are
clogged.
2. Improper fan rotation of cooling fan. Clean condenser.
Check and repair cooling fan
as necessary.
Low-pressure pipe is not cold.
When compressor is stopped high-pressure val-
ue quickly drops by approx-
imately 196 kPa (2 kg/cm
2,
28 psi). It then decreases
gradually thereafter. Poor heat exchange in con-
denser
(After compressor operation
stops, high-pressure decreas-
es too slowly.).
↓
Air in refrigeration cycle.
Evacuate repeatedly and re-
charge system.
Engine tends to overheat. Engine cooling systems mal-
function. Check and repair each engine
cooling system.
An area of the low-pressure pipe is colder than areas
near the evaporator outlet.
Low-pressure pipe is some- times covered with frost. Excessive liquid refrigerant
on low-pressure side.
Excessive refrigerant dis- charge flow.
Expansion valve is open a lit- tle compared with the speci-
fication.
↓
Improper expansion valve ad-
justment. 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 lo-
cated between compressor
and condenser are clogged or
crushed. Check and repair or replace
malfunctioning parts.
Check lubricant 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 opera-
tion is improper.
↓
Damaged inside compressor
packings.
Replace compressor.
No temperature difference be-
tween high- and low-pressure
sides. Compressor pressure opera-
tion is improper.
↓
Damaged inside compressor
packings.
Replace compressor.
AC356A
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ATC-80
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
Low-pressure Side Sometimes Becomes Negative
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
difference between liquid
tank outlet and inlet. Outlet
temperature is extremely
low.
Liquid tank inlet and expan-
sion valve are frosted. Liquid tank inside is slightly
clogged.
Replace liquid tank.
Check lubricant for contami-
nation.
Temperature of expansion valve inlet is extremely low
as compared with areas
near liquid tank.
Expansion valve inlet is frosted.
Temperature difference oc- curs somewhere in high-
pressure side. High-pressure pipe located be-
tween liquid tank and expan-
sion valve is clogged.
Check and repair malfunc-
tioning parts.
Check lubricant for contami- nation.
Expansion valve and liquid
tank are warm or slightly cool
when touched. Low refrigerant charge.
↓
Leaking fittings or compo-
nents.
Check refrigerant for leaks.
Refer to
ATC-138, "
Checking
of Refrigerant 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 specifica-
tion.
↓
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 lubricant for contami-
nation.
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 lubricant for contami- nation.
Air flow volume is not enough
or is too low. Evaporator is frozen. Check intake sensor circuit.
Refer to AT C - 9 4 , "
Intake
Sensor Circuit".
Replace compressor.
Repair evaporator fins.
Replace evaporator.
Refer to AT C - 6 4 , "
Blower
Motor Circuit".
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
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TROUBLE DIAGNOSISATC-81
< SERVICE INFORMATION >
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DIAGNOSIS PROCEDURE FOR INSUFFICIENT COOLING
SYMPTOM: Insufficient cooling
1.CHECK POWER SUPPLY FOR ECV (ELECTRONIC CONTROL VALVE)
1. Disconnect compressor (ECV) connector.
2. Turn ignition switch ON.
3. Check voltage between compressor (ECV) harness connector F6 terminal 2 and ground.
OK or NG
OK >> GO TO 2.
NG >> Check power supply circuit and 10A fuse [No. 12, located in the fuse block (J/B)]. Refer to PG-77
.
If fuse is OK, check harness for open circuit. Repair or replace if necessary.
If fuse is NG, check harness for short circuit and replace fuse.
2.CHECK ECV CONTROL SIGNAL
1. Turn ignition switch OFF.
2. Reconnect compressor (ECV) connector.
3. Perform self-diagnosis. Refer to ATC-43, "
Self-Diagnosis Function".
4. Set in self-diagnosis STEP-4 (Code No. 45). Refer to ATC-43, "
Self-Diagnosis Function".
5. Confirm ECV control signal between unified meter and A/C amp. harness connector M57 terminal 45 and ground using an oscillo-
scope.
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 wet with dew.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 lubricant for contami-
nation.
AC362A
2 – ground : Battery voltage
RJIA2294E
RJIA2295E
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ATC-82
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
OK or NG
OK >> Replace compressor.
NG >> GO TO 3.
3.CHECK CIRCUIT CONTINUITY BETWEEN ECV AND UNIFIED METER AND A/C AMP.
1. Turn ignition switch OFF.
2. Disconnect compressor (ECV) and unified meter and A/C amp. connector.
3. Check continuity between compressor (ECV) harness connector F6 terminal 3 and unified meter and A/C amp. harness connec-
tor M57 terminal 45.
OK or NG
OK >> GO TO 4.
NG >> Repair harness or connector.
4.CHECK ECV
Check continuity between compressor (ECV) connector F6 terminals
2 and 3.
OK or NG
OK >> Replace unified meter and A/C amp.
NG >> Replace compressor.
Insufficient HeatingINFOID:0000000001328192
SYMPTOM: Insufficient heating
INSPECTION FLOW
SJIA1765E
3 – 45 : Continuity should exist.
RJIA2296E
2 – 3 : Continuity should exist.
RJIA2297E
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TROUBLE DIAGNOSISATC-83
< SERVICE INFORMATION >
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NoiseINFOID:0000000001328193
SYMPTOM: Noise
INSPECTION FLOW
*1 AT C - 5 0 , "Operational Check"*2AT C - 5 9 , "Air Mix Door Motor Circuit"*3AT C - 4 3 , "Self-Diagnosis Function",
see No. 4 to 6.
*4 AT C - 4 3 , "
Self-Diagnosis Function",
see No. 13. *5
AT C - 5 4 , "LAN System Circuit"*6AT C - 6 4 , "Blower Motor Circuit"
*7 EC-193 (VQ35DE) or EC-779
(VK45DE) *8
CO-10, "Changing Engine Coolant"
(VQ35DE) or CO-37, "
Changing En-
gine Coolant" (VK45DE) *9
CO-14, "
Checking Radiator Cap"
(VQ35DE) or CO-42, "
Checking Ra-
diator Cap" (VK45DE)
SJIA1593E
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