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Performance diagnosis table
HIGH PRESSURE GAUGE
LOW PRESSURE GAUGE
NOTE:
If ambient temperature is approximately 30 °C (86 °F), it is possible to diagnose A/C system in detail
referring to “Detail Diagnosis Table (Ambient Temperature At 30 °C (86 °F))” under “Performance
Diagnosis” in this section.
Condition Possible Cause Correction
Pressure in higher
than acceptable range
(“A” area)Refrigerant overcharged Recharge
Expansion valve frozen or clogged Check expansion valve
Clogged refrigerant passage of high side Clean or replace
Condenser cooling fan malfunction (Insufficient
cooling of condenser)Check condenser cooling fan
Dirty or bent condenser fins (Insufficient cooling
of condenser)Clean or repair
Compressor malfunction (Insufficient oil etc.) Check compressor
Engine overheat Check engine cooling system refer-
ring to Section 6B.
Pressure is lower than
acceptable range
(“B” area)Insufficient refrigerant (Insufficient charge or
leakage)Check for leakage, repair if neces-
sary and recharge
Expansion valve malfunction (valve opens too
wide)Check expansion valve
Compressor malfunction (Insufficient compres-
sion)Check compressor
Condition Possible Cause Correction
Pressure is higher
than acceptable range
(“C” area)Expansion valve malfunction (valve opens too
wide)Check expansion valve
Compressor malfunction (Insufficient compres-
sion)Check compressor
Pressure is lower than
acceptable range
(“D” area)Insufficient refrigerant (Insufficient charge or
leakage)Check for leakage, repair if neces-
sary and recharge
Expansion valve malfunction (valve opens too
narrow)Check expansion valve
Clogged refrigerant passage (crashed pipe) Repair or replace
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CROSSING POINT OF CENTER VENTILATION LOUVER TEMPERATURE AND RECIRCULATION AIR
INLET TEMPERATURE
Detail diagnosis table (Ambient temperature at 30°C (86°F))
Condition Possible Cause Correction
Crossing point is
higher than accept-
able 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
GAUGEMPa
(kg/cm
2)
(psi)Detail
Lo Hi
0.23 – 0.35
(2.3 – 3.5)
(33 – 50)1.4 – 1.75
(14 – 17.5)
(200 – 249)Normal condition
––
Negative
pressure0.5 – 0.6
(5 – 6)
(71.2 – 85.3)The low pressure side
reads a negative pres-
sure, and the high pres-
sure 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 expan-
sion valve, preventing the
refrigerant from flowing.Clean expansion valve.
Replace it if it cannot be
cleaned.
Replace receiver / dryer.
Evacuate the A/C sys-
tem and recharge with
fresh refrigerant.
Normal :
0.23 – 0.35
(2.3 – 3.5)
(33 – 50)
↑
↑ ↑ ↑ ↓
↓↓ ↓
Abnormal :
Negative
pressureNormal :
1.4 – 1.75
(14 – 17.5)
(200 – 249)
↑
↑ ↑ ↑ ↓
↓↓ ↓
Abnormal :
0.69 – 0.98
(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 receiver / dryer.
Evacuate A/C system
and recharge with fresh
refrigerant.
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0.05 – 0.15
(0.5 – 1.5)
(4.2 – 21.3)
0.69 – 0.98
(7 – 10)
(100 – 142)Both low and high pres-
sure sides indicate low
readings.
Continuous air bub-
bles are visible through
sight glass.
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 mani-
fold gauges are attached,
check for any leaks,
repair them, and evacu-
ate the system.
0.4 – 0.6
(4 – 6)
(56.9 – 85.3)Pressure on low pres-
sure side is high.
Pressure on high pres-
sure side is low.
Both pressure becom-
ing equal right after A/C
is turned OFF.Internal leak in compres-
sor.Inspect compressor and
repair or replace as nec-
essary.
0.35 – 0.45
(3.5 – 4.5)
(50 – 64)
1.96 – 2.45
(20 – 25)
(285 – 355)Pressure on both low
and high pressure
sides is high.
Air bubbles are not visi-
ble even when engine
rpm is lowered.Overcharged A/C sys-
tem.Adjust refrigerant to
specified amount.
Faulty condenser cooling
operation.Clean condenser.
Faulty condenser cooling
fan operation.Inspect and repair con-
denser cooling fan.
Pressure on both low
and high pressure
sides is high.
Low pressure side tub-
ing is not cold when
touched.
Air bubbles are visible
through sight glass.Presence of air in A/C
system.
(Improperly evacuated)Replace receiver / dryer.
Inspect quantity of com-
pressor oil and presence
of contaminants in oil.
Evacuate system and
recharge with fresh
refrigerant.
0.45 – 0.55
(4.5 – 5.5)
(64 – 78)Pressure on both low
and high pressure
sides is high.
Large amount of frost
or dew on the low pres-
sure side tubing.Faulty expansion valve.
Refrigerant flow is not
regulated properly.Replace expansion valve. Condition
Possible Cause Correction MANIFOLD
GAUGEMPa
(kg/cm
2)
(psi)Detail
Lo Hi
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Compressor Drive Belt
INSPECTION
Check belt for wear and cracks, and replace as required.
Check belt tension by measuring how much it deflects when
pushed at intermediate point between compressor pulley (1)
and crankshaft pulley (2) with about 100 N (10 kg, 22 lb)
force.
If belt tension is out of above specification, adjust belt ten-
sion according to the following procedures.
Deflection of compressor drive belt
“a” : 6 – 9 mm (0.24 – 0.35 in.)
ADJUSTMENT
For Vehicle With P/S
1) Loosen tension pulley bolts (3) and set hexagon wrench (4)
to hexagon hole.
2) Turn tension pulley (5) counterclockwise by hexagon wrench
in order to obtain above specified tension.
3) Tighten tension pulley bolts (3) to specified torque.
Tightening torque
Tension pulley bolts
(a) : 25N·m (2.5 kg-m, 18.0 lb-ft)
For Vehicle Without P/S
1) Loosen tension pulley tightening nut (6).
2) Adjust belt tension by tighten or loosen tension pulley adjust-
ing bolt (7) in order to obtain above specified tension.
3) Tighten tension pulley tightening nut (6).
[A] : Vehicle with P/S
[B] : Vehicle without P/S
Page 77 of 687
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Electronical Diagnosis
Wiring Diagram
[A]: 4WD model 4. Dual pressure switch 9. Thermal switch 14. Circuit fuse box
[B]: 2WD model 5. 4WD controller 10. Ignition switch 15. Main fuse box
1. Blower fan motor 6. Condenser cooling fan motor relay 11. A/C evaporator thermistor 16. Generator
2. Blower fan motor resistor 7. Condenser cooling fan motor 12. ECT sensor 17. ECM
3. Blower fan motor switch and A/C switch 8. Compressor 13. Lighting switch
Page 78 of 687
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A/C System Inspection of ECM and ITS Cir-
cuits
ECM and its circuits can be checked at ECM wiring couplers by
measuring voltage.
Voltage Check
1) Remove ECM from vehicle by referring to “Engine Control
Module” in Section 6E.
2) Connect ECM couplers (1) to ECM (2).
3) Check voltage at each terminal of couplers connected.CAUTION:
ECM cannot be checked by itself. It is strictly prohibited
to connect voltmeter or ohmmeter to ECM with couplers
disconnected from ECM.
NOTE:
Because each terminal voltage is affected by the battery
voltage, confirm that the battery voltage is 11 V or more
when ignition switch is ON.
[A] : Fig. A
[B] : Fig. B
3. E19-3
Page 79 of 687
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Terminal arrangement of ECM coupler (Viewed from harness side)
1. Blower fan motor 8. Compressor [A]: To “A/C” fuse (25A) in main fuse box
2. Dual pressure switch 9. Thermal switch [B]: To “HEATER” fuse (20A) in circuit fuse box
3. A/C switch 10. Main relay [C]: To “FI” fuse (15A) in main fuse box
4. A/C evaporator thermistor 11. Engine earth [D]: 4WD model
5. ECT sensor 12. Blower fan motor switch [E]: 2WD model
6. Condenser cooling fan motor relay 13. 4WD controller
7. Condenser cooling fan motor 14. ECM
Page 80 of 687

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ECM VOLTAGE VALUES TABLE FOR RELATION OF A/C CONTROL
Terminal Wire CircuitMeasurement
groundNormal value Condition
E18-1 PCompressor
magnet clutch
outputGround to
engine (Fig B)10 – 14 voltBlower fan motor switch and A/C
switch ON with engine running
0 – 1 voltsExcept the above-mentioned condi-
tion with engine running
E18-5 Bl/BMain power sup-
ply for ECMGround to
engine (Fig B)10 – 14 voltsIgnition switch ON with engine
stopped
E18-6 Bl/BMain power sup-
ply for ECMGround to
engine (Fig B)10 – 14 voltsIgnition switch ON with engine
stopped
E18-10 Bl Main relay driveGround to
engine (Fig B)0.5 – 1.2 voltIgnition switch ON with engine
stopped
0 volts Ignition switch OFF
E18-16 G/W A/C switch inputGround to
engine (Fig B)12 – 15 voltsBlower fan motor switch or A/C switch
OFF with engine running
0 – 1 voltBlower fan motor switch and A/C
switch ON with engine running
12 – 15 voltsWithin several seconds after operate
transfer lever between 2WD and 4WD
with above condition
E18-18 P/BCompressor
cooling fan relay
outputGround to
engine (Fig B)0 – 1 voltBlower fan motor switch and A/C
switch ON or engine coolant tempera-
ture at more than 110 °C (230 °F) with
engine running.
12 – 15 voltsExcept the above-mentioned condi-
tion with engine running
E18-20 B/BlSensor ground
for A/C evapora-
torGround to
body (Fig A)–0.5 – 0 volt Engine running
E18-24 Bl/YBlower fan
speed inputGround to
engine (Fig B)0 – 1 voltBlower fan motor switch 2nd or 3rd
with engine running
4 – 7 voltsBlower fan motor switch 1st with
engine running
12 – 15 voltsBlower fan motor switch and A/C
switch OFF with engine running
E19-1 BMain ground for
ECMGround to
engine (Fig A)–0.5 – 1 volt Engine running
E19-2 B/RECM ground for
power circuitGround to
engine (Fig A)–0.5 – 1 volt Engine running
E19-3 B/RECM ground for
power circuitGround to
engine (Fig A)–0.5 – 1 volt Engine running
E19-10 B/BlSensor ground
for ECT sensorGround to
body (Fig A)–0.5 – 1 volt Engine running