Page 2388 of 2771

MTC-50
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
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
Page 2389 of 2771

TROUBLE DIAGNOSIS
MTC-51
< SERVICE INFORMATION >
C
D
E
F
G
H
I
K
L
MA
B
MTC
N
O
P 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 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-84, "
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-37, "
Magnet
Clutch Circuit (If Equipped)"
.
• Replace compressor.
• Repair evaporator fins.
• Replace evaporator.
• Refer to MTC-33, "
Front
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
Page 2390 of 2771

MTC-52
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
Insufficient Heating
INFOID:0000000001704307
SYMPTOM: Insufficient heating
INSPECTION FLOW
1.CONFIRM SYMPTOM BY PERFORMING OPERATIONAL CHECK - TEMPERATURE DECREASE
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-30, "
Operational Check" .
Does another symptom exist?
YES >> Refer to MTC-22, "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-8
.
2. Check hoses for leaks or kinks.
3. Check Radiator cap. Refer to CO-13, "
Checking Radiator Cap" .
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-64, "
Air Mix Door Cable Adjustment" .
OK or NG
YES >> GO TO 6.
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
Page 2392 of 2771
MTC-54
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
*1.MTC-30, "Operational Check"*2.MTC-78, "Removal and Installation of
Compressor"
*3.MTC-16, "Maintenance of Oil Quanti-
ty in Compressor"
*4.EM-13, "Checking Drive Belts"*5.MTC-78, "Removal and Installation of
Compressor"
WJIA2226E
Page 2395 of 2771
THERMO CONTROL AMPLIFIER
MTC-57
< SERVICE INFORMATION >
C
D
E
F
G
H
I
K
L
MA
B
MTC
N
O
P
THERMO CONTROL AMPLIFIER
Removal and InstallationINFOID:0000000001704311
NOTE:
Only TYPE 1 systems are equipped with a thermo control amplifier.
REMOVAL
1. Remove evaporator. Refer to MTC-83, "Removal and Installation of Evaporator" .
CAUTION:
Cap or wrap the joint of the pipe with suitable material such as vinyl tape to avoid the entry of air.
2. Remove thermo control amp. (1) from evaporator (2).
INSTALLATION
Installation is in the reverse order of removal.
CAUTION:
• Replace O-rings for A/C piping with new ones, and apply compressor oil when installing.
• Mark the mounting position of thermo control amp.
• When recharging refrigerant, check for leaks.
ZJIA0798J
Page 2397 of 2771

A/C UNIT ASSEMBLY
MTC-59
< SERVICE INFORMATION >
C
D
E
F
G
H
I
K
L
MA
B
MTC
N
O
P
8. Remove instrument stay nuts (A) and harness clamps (B), and
then remove instrument stay (1).
9. Disconnect thermo control amp. connector (1) for TYPE 1 sys-
tems as shown. Disconnect the thermo control amp. short con-
nector for TYPE 2 systems.
10. Remove instrument panel and pad. Refer to IP-10
.
11. Remove side ventilator ducts. Refer to MTC-69, "
Removal and Installation" .
12. Remove center ventilator ducts. Refer to MTC-69, "
Removal and Installation" .
13. Remove side kicking plates. Refer to EI-37
.
14. Disconnect the fuel filler door cable and the rear hatch door cable.
15. Remove A/C unit assembly bolts, steering member bolts, steering column nuts and harness clips.
16. Remove steering member, and then remove A/C unit assembly.
INSTALLATION
Installation is in the reverse order of removal.
• When filling radiator with coolant, refer to CO-8, "
Changing Engine Coolant" .
• Recharge the refrigerant.
CAUTION:
• Replace O-rings for A/C piping with new ones, and apply compressor oil when installing.
• When recharging refrigerant, check for leaks.
SJIA0646E
SJIA0647E
A/C unit assembly bolt : 6.9 N·m (0.7 kg-m, 61 in-lb)
Steering member bolt : 12 N·m (1.25 kg-m, 9 ft-lb)
Steering column nut : Refer to PS-9
.
Page 2412 of 2771

MTC-74
< SERVICE INFORMATION >
REFRIGERANT LINES
REFRIGERANT LINES
HFC-134a (R-134a) Service ProcedureINFOID:0000000001704322
SETTING OF SERVICE TOOLS AND EQUIPMENT
Discharging Refrigerant
WARNING:
Avoid breathing A/C refrigerant and oil vapor or mist. Exposure may irritate eyes, nose and throat.
Remove HFC-134a (R-134a) refrigerant from the A/C system using certified service equipment meeting
requirements of SAE J2210 HFC-134a (R-134a) recycling equipment or SAE J2201 HFC-134a (R-134a)
recovery equipment. If an accidental system discharge occurs, ventilate the work area before resum-
ing service. Additional health and safety information may be obtained from the refrigerant and oil man-
ufacturers.
Evacuating System and Charging Refrigerant
1. Shut-off valve 2. A/C service valve 3. Recovery/recycling equipment
A. Preferred (best) method
WJIA2195E
1. Shut-off valve 2. A/C service valve 3. Recovery/recycling equipment
4. Refrigerant container (HFC-134a) 5. Weight scale (J-39650) 6. Evacuating vacuum pump (J-39699)
WJIA2196E
Page 2413 of 2771
REFRIGERANT LINES
MTC-75
< SERVICE INFORMATION >
C
D
E
F
G
H
I
K
L
MA
B
MTC
N
O
P
7. Manifold gauge set (J-39183) A. Preferred (best) method B. Alternative method
C. For charging
*1MTC-16, "
Maintenance of Oil Quanti-
ty in Compressor"
*2MTC-84, "Checking of Refrigerant
Leaks"
*3MTC-85, "Electronic Refrigerant
Leak Detector"
*4MTC-45, "Insufficient Cooling"
WJIA1923E