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MTC-50
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
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.
TROUBLE DIAGNOSIS FOR ABNORMAL PRESSURE
Whenever system’s high and/or low side pressure(s) is/are abnormal, 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).
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 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)
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 - 70 20 (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 - 70 20 (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)
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TROUBLE DIAGNOSISMTC-51
< SERVICE INFORMATION >
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MTC
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Both High- and Low-pressure Sides are Too High
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
Gauge indication
Refrigerant cycle Probable causeCorrective 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 causeCorrective 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 causeCorrective 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
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MTC-52
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
Both High- and Low-pressure Sides are Too Low
Low-pressure Side Sometimes Becomes Negative
Low-pressure Side Becomes Negative
Gauge indication Refrigerant cycle Probable causeCorrective 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
MTC-92, "
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 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 MTC-38, "
Magnet
Clutch Circuit (If Equipped)"
.
• Replace compressor.
• Repair evaporator fins.
• Replace evaporator.
•Refer to MTC-34, "
Front
Blower Motor Circuit" .
AC353A
Gauge indication Refrigerant cycleProbable causeCorrective 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 DIAGNOSISMTC-53
< SERVICE INFORMATION >
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Insufficient HeatingINFOID:0000000005396504
SYMPTOM: Insufficient heating
INSPECTION FLOW
1.CONFIRM SYMPTOM BY PERFORMING OPERAT IONAL CHECK - TEMPERATURE INCREASE
1. Turn temperature control dial clockwise to maximum heat position.
2. Check for hot 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 MTC-31, "
Operational Check" .
Does another symptom exist?
YES >> Refer to MTC-23, "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 COOLANT SYSTEM
1. Check engine coolant level. Refer to CO-12, "
Inspection" (HR16DE) or CO-36, "Inspection" (MR18DE).
2. Check hoses for leaks or kinks.
3. Check Radiator cap. Refer to CO-15, "
Checking Radiator Cap" HR16DE or CO-39, "Checking Radiator
Cap" (MR18DE).
OK or NG
OK >> GO TO 5.
NG >> Repair/replace as necessary.
5.CHECK AIR MIX DOOR CABLE
Check air mix door cable operation. Refer to MTC-65, "
Air Mix Door Cable Adjustment" .
OK or NG
Gauge indication Refrigerant cycleProbable causeCorrective 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
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MTC-54
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
YES >> GO TO 6.
NO >> Adjust or replace air mix door cable. Refer to MTC-65, "
Air Mix Door Cable Adjustment" .
6.CHECK AIR DUCTS
Check ducts for air leaks.
OK or NG
OK >> GO TO 7.
NG >> Repair air leaks.
7.CHECK HEATER HOSE TEMPERATURES
1. Start engine and warm it up to normal operating temperature.
2. Touch both the inlet and outlet heater hoses. The inlet hose should be hot and the outlet hose should be
warm.
Is the inlet hose hot and the outlet hose warm?
YES >> GO TO 8.
NO >> Both hoses warm: GO TO 9.
8.CHECK ENGINE COOLANT TEMPERATURE SENSOR
Check engine control temperature sensor. Refer to EC-690, "
Component Inspection" (MR18DE) or EC-163,
"Component Inspection" (HR16DE).
OK or NG
OK >> System OK.
NG >> Repair or replace as necessary. Retest.
9.CHECK HEATER HOSES
Check heater hoses for proper installation.
OK or NG
OK >> GO TO 10.
NG >> Repair /replace as necessary. Retest GO TO 7.
10.BACK FLUSH HEATER CORE
1. Back flush heater core.
2. Drain the water from the system.
3. Refill system with new engine coolant. Refer to CO-12, "
Changing Engine Coolant" (HR16DE) or CO-36,
"Changing Engine Coolant" (MR18DE) .
4. Start engine and warm it up to normal operating temperature.
5. Touch both the inlet and outlet heater hoses. The inlet hose should be hot and the outlet hose should be
warm.
Is the inlet hose hot and the outlet hose warm?
YES >> System OK.
NO >> Replace heater core and refill engine coolant. Refer to MTC-68, "
Removal and Installation" .
NoiseINFOID:0000000005396505
SYMPTOM: Noise
INSPECTION FLOW
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TROUBLE DIAGNOSISMTC-55
< SERVICE INFORMATION >
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*1. MTC-31, "Operational Check"*2.EM-14, "Checking" (HR16DE) or EM-
132, "Checking Drive Belts"
(MR18DE) *3.
MTC-46, "
Insufficient Cooling"
*4.MTC-92, "Removal and Installation of
Expansion Valve"
*5.MTC-79, "Removal and Installation of
Compressor - HR16DE" or MTC-81,
"Removal and Installation of Com-
pressor - MR18DE"
*6 MTC-79, "Removal and Installation of
Compressor - HR16DE" or MTC-81,
"Removal and Installation of Com-
pressor - MR18DE"
*7. MTC-79, "Removal and Installation of
Compressor - HR16DE" or MTC-81,
"Removal and Installation of Com-
pressor - MR18DE"
*8.MTC-17, "Maintenance of Oil Quanti-
ty in Compressor"
*9 MTC-90, "Removal and Installation of
Liquid Tank"
AWIIA1001GB
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MTC-56
< SERVICE INFORMATION >
CONTROLLER
CONTROLLER
Removal and InstallationINFOID:0000000005396506
REMOVAL
1. Remove cluster lid C and instrument finisher D. Refer to IP-11, "Component Parts" .
2. Remove intake door lever knob. Refer to MTC-57, "
Disassembly and Assembly" .
3. Remove mounting screws and clips, and then remove controller finisher.
4. Remove mounting screws, and then pull out controller.
5. Remove instrument panel and pad. Refer to IP-11, "
Component Parts" .
6. Remove air mix door cable, mode door cable and intake door cable from A/C unit assembly.
7. Disconnect connector, and then remove controller.
INSTALLATION
Installation is in the reverse order of removal.
CAUTION:
Adjust the door cables duri ng installation. Refer to MTC-64, "
Intake Door Cable Adjustment" , MTC-66,
"Mode Door Cable Adjustment" and MTC-65, "Air Mix Door Cable Adjustment" .
ZJIA0697E
ZJIA0698E
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CONTROLLERMTC-57
< SERVICE INFORMATION >
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Disassembly and AssemblyINFOID:0000000005396507
CAUTION:
Install inner cable of each do or cable to the corresponding
lever, as shown in the figure. Pr ess outer cable until it hooks on
the tabs and becomes secure.
1. Air mix door cable 2. Intake door cable3. Mode door cable
4. A/C controller assembly 5. Mode control dial6. Rear DEF button
7. A/C button 8. Temperature control dial9. Illumination bulb
10. Intake door lever knob 11. Fan control dial
ZJIA0106J
MJIA0038E
Revision: January 20102010 Versa