
1B-10 AIR CONDITIONING (OPTIONAL)
Performance Diagnosis
1) Confirm that vehicle and environmental conditions are as fol-
lows.
Vehicle is not exposed to direct sun.
Ambient temperature is within 15 - 35 °C (59 - 95 °F).
2) Make sure that high pressure valve (1) and low pressure
valve (2) of manifold gauge (3) are firmly closed.
3) Connect high pressure charging hose (4) to high pressure
service valve (5) on vehicle, and connect low pressure
charging hose (6) to low pressure service valve (7) on vehi-
cle.
4) Bleed the air in charging hoses (3), (4) by loosening their
respective nuts on manifold gauge, utilizing the refrigerant
pressure. When a hiss is heard, immediately tighten nut.
5) Warm up engine to normal operating temperature (engine
coolant temperature at 80 - 90 °C (176 - 194 °F)) and keep it
at specified idle speed.
6) Operate A/C at the following conditions.
Main (front) A/C switch at ON position.
Rear A/C main switch at ON position (if equipped).
Front blower motor switch at max position.
Rear blower motor switch at max position (if equipped).
Air outlet control button at face position.
Temperature control lever at max cool position.
Vehicle door at all open.
Air inlet door at recirculation position.
7) Keep all windows, doors and engine food open.
8) With about 20 mm (0.8 in.) of dry bulb thermometer (1)
inserted into center face air outlet (2), rear A/C air outlet (3)
(dual A/C model only) and near A/C evaporator air inlet, read
temperature indicated on each thermometer. CAUTION:
Do not interchange high and low pressure charging
hoses by mistake.
2
64
3
75 1
3
1
2

AIR CONDITIONING (OPTIONAL) 1B-11
9) Check for each pressure of low side and high side if it is
within shaded range of graph.
If each gauge reading is out of specified pressure, correct
defective part referring to “PERFORMANCE DIAGNOSIS
TABLE”.
Example :
10) Check inlet port temperature-to-outlet port temperature rela-
tionship using graph.
For example, if A/C evaporator inlet port temperature is 25
°C (77 °F) and center face air outlet temperature is 8 °C
(46.4 °F), their crossing point is within acceptable range as
shown in graph.
11) If crossing point is out of acceptable range, diagnose trouble
referring to “PERFORMANCE DIAGNOSIS TABLE”.
12) Check that difference in temperature of center face air outlet
air and rear A/C air outlet air are within 5 °C (41 °F).
If the rear A/C air outlet air temperature is higher over 5 °C
(41 °F) than center face air outlet air temperature, check rear
A/C unit. Gauges should read as follows
when ambient temperature is 30 °C (86 °F)
Pressure on high pressure
gauge (HI) :1400 - 1750 kPa
14.0 - 17.5 kg/cm
2
199.1 - 248.9 psi
Pressure on high pressure
gauge (LO) :230 - 350 kPa
2.3 - 3.5 kg/cm
2
32.7 - 49.8 psi
NOTE:
Pressure registered on gauge varies with ambient tem-
perature. Therefore, use the graphs when determining if
pressures are normal or not.

1B-12 AIR CONDITIONING (OPTIONAL)
Performance diagnosis table
HIGH PRESSURE GAUGE
LOW PRESSURE GAUGE
THERMOMETER AT CENTER DUCT
Condition Possible Cause Correction
Pressure high
(“A” area of high side
graph)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 con-
denser)Clean or repair.
Compressor malfunction (Insufficient oil etc.) Check compressor.
Engine overheat Check engine cooling system.
Pressure low
(“B” area of high side
graph)Insufficient refrigerant (Insufficient charge or leakage) Check for leakage, repair if necessary
and recharge.
Expansion valve malfunction (valve opens too wide) Check expansion valve.
Compressor malfunction (Insufficient compression) Check compressor.
Condition Possible Cause Correction
Pressure high
(“C” area of low side
graph)Expansion valve malfunction (valve opens too wide) Check expansion valve.
Compressor malfunction (Insufficient compression) Check compressor.
Pressure low
(“D” area of low side
graph)Insufficient refrigerant (Insufficient charge or leakage) Check for leakage, repair if necessary
and recharge.
Expansion valve malfunction (valve opens too narrow) Check expansion valve.
Clogged refrigerant passage (crashed pipe) Repair or replace.
Condition Possible Cause Correction
Outlet air temperature at
center duct is high
(Crossing point is in area
“E”)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 damper in cool-
ing (heater) unitRepair or replace.
Compressor malfunction Check compressor.
Outlet air temperature at
center duct is low
(Crossing point is in area
“F”)Insufficient air volume from center duct (Heater blower
malfunction)Check blower motor and fan.
Compressor malfunction Check compressor.
NOTE:
If ambient temperature is within 30 - 35 °C (85 - 95 °F), it is possible to do using “DETAIL DIAGNOSIS
TABLE” in this section for detail diagnosis.

AIR CONDITIONING (OPTIONAL) 1B-13
Detail diagnosis table (at ambient temperature within 30 - 35 °C (85 - 95 °F))
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 pressure,
and the high pressure side
reads an extremely low
pressure.
Presence of frost around
tubing to and from receiver/
dryer and expansion valve.Dust particles or water drop-
lets are either stuck or frozen
inside expansion valve, pre-
venting the refrigerant from
flowing.Clean expansion valve.
Replace it if it cannot be
cleaned.
Replace condenser/dryer.
Evacuate the A/C system and
recharge with fresh refriger-
ant.
Normal :
0.23 - 0.35
(2.3 - 3.5)
(33 - 50)
↑ ↓
↑ ↓↑ ↓ ↑ ↓
Abnormal :
Negative
pressureNormal :
1.4 - 1.75
(14 - 17.5)
(200 - 249)
↑ ↓
↑ ↓↑ ↓ ↑ ↓
Abnormal :
0.7 - 1.0
(7 - 10)
(100 - 142)During A/C operation, the
low pressure side some-
times indicates negative
pressure, and sometimes
normal pressure. Also high
pressure side reading fluc-
tuates between the abnor-
mal and normal pressure.Expansion valve is frozen due
to moisture in the system, and
temporarily shuts off the
refrigeration cycle.Replace expansion valve.
Replace condenser/dryer.
Evacuate A/C system and
recharge with fresh refriger-
ant.
0.05 - 0.15
(0.5 - 1.5)
(4.2 - 21.3)0.7 - 1.0
(7 - 10)
(100 - 142)Both low and high pressure
sides indicate low readings.
Continuous air bubbles are
visible through sight glass.
Output air is slightly cold.Insufficient refrigerant in sys-
tem. (Refrigerant leaking)Using a gas leak detector,
check for leaks and repair as
necessary.
Recharge refrigerant to a
specified amount.
If the pressure reading is
almost 0 when the manifold
gauges are attached, check
for any leaks, repair them,
and evacuate the system.
0.4 - 0.6
(4 - 6)
(56.9 - 85.3)Pressure on low pressure
side is high.
Pressure on high pressure
side is low.
Both pressure becoming
equal right after A/C is
turned OFF.Internal leak in compressor Inspect compressor and
repair or replace as neces-
sary.
0.35 - 0.45
(3.5 - 4.5)
(50 - 64)2.0 - 2.5
(20 - 25)
(285 - 355)High pressure reading on
both low and high pressure
sides.
Air bubbles are not visible
even when engine rpm is
lowered.Overcharged A/C system.
Faulty condenser cooling
operation.
Faulty condenser fan opera-
tion.Adjust refrigerant to specified
amount.
Clean condenser.
Inspect and repair condenser
fan.
High pressure reading on
both low and high pressure
sides.
Low pressure side tubing is
not cold when touched.
Air bubbles are visible
through sight glass.Presence of air in A/C sys-
tem. (Improperly evacuated)Replace condenser dryer.
Inspect quantity of compres-
sor oil and presence of con-
taminants in oil.
Evacuate system and
recharge with fresh refriger-
ant.
0.45 - 0.55
(4.5 - 5.5)
(64 - 78)High pressure reading on
both low and high pressure
sides.
Large amount of frost or
dew on the low pressure
side tubing.Faulty expansion valve.
Refrigerant flow is not regu-
lated properly.Replace expansion valve.

AIR CONDITIONING (OPTIONAL) 1B-15
Inspection of A/C Controller and Its Circuits
A/C Controller (1) and its circuits can be checked at A/C controller
wiring couplers by measuring voltage.
Voltage check
1) Remove A/C controller (1) from vehicle referring to “A/C
CONTROLLER” in this section.
2) Remove ECM (2) from vehicle.
3) Connect A/C controller couplers to A/C controller and con-
nect ECM couplers to ECM.
4) Check each terminal voltage with couplers connected by
referring to “A/C CONTROLLER VOLTAGE VALUES TABLE”. CAUTION:
A/C controller and ECM cannot be checked by itself.
It is strictly prohibited to connect voltmeter or ohmmeter
to A/C controller and ECM with couplers disconnected
from it.
3. Terminal AC-A-2
4. Terminal C51-3-6
NOTE:
For “Fig. A”, “Fig. B”, “Fig. C” in the figure, refer to “A/C
CONTROLLER VOLTAGE VALUES TABLE”.

1B-18 AIR CONDITIONING (OPTIONAL)
Terminal Wire CircuitMeasurement
groundNormal value Condition
AC-B-2WHT/
BLKA/C evaporator
temperature
sensor (A/C
evaporator ther-
mistor) inputGround to
engine (Fig B)1.8 V
(3520 Ω)A/C evaporator temperature sen-
sor temperature at approx. 15 °C
(59 °F) with engine running
2.51 V
(5.855 Ω)A/C evaporator temperature sen-
sor temperature at approx. 4.5 °C
(34 °F) with engine running
If the temperature is less than
approx. 4.5 °C, in this case com-
pressor and condenser fan
should be stop (come back at
more than approx. 6.1 °C (less
than 5403 Ω, 2.4 V))
E61-8GRY/
WHTSignal output to
A/C controller
(A/C ON permis-
sion signal)Ground to
engine (Fig C)10 – 14 VRequired A/C ON (terminal AC-
A13) at engine running with nor-
mal condition (refer to “INSPEC-
TION OF ECM AND ITS
CIRCUIT” in Section 6E)
0 – 1 VExcept the above-mentioned with
engine running
In this case compressor should
be stop
E61-17YEL/
BLKSignal input from
A/C controller
(A/C ON request
signal)Ground to
engine (Fig C)0 – 1.5 V Require A/C ON
10 – 14 V Turn off the A/C
E61-22YEL/
BLUCondenser cool-
ing fan motor
relay outputGround to
engine (Fig C)0 – 1 VBlower fan motor switch and A/C
or defroster switch ON with
engine running at A/C evaporator
temperature sensor temperature
input more than approx. 2.5 °C
(less than 2.5 V (5840 Ω)), refrig-
erant pressure switch ON and
signal input from ECM ON
Engine coolant temperature sen-
sor more than 113 °C (236 °F)
with engine running
10 – 14 VExcept the above-mentioned with
engine running

AIR CONDITIONING (OPTIONAL) 1B-19
Refrigerant Recovery, Evacuation and Charging
Operation Procedure for Charging A/C with Refrigerant
WARNING:
Your eyes should not be exposed to refrigerant (liquid).
Any liquid Refrigerant-134a escaping by accident shows a temperature as low as approx. –6 °C
(21.2 °F) below freezing point. Should liquid HFC-134a (R-134a) get into your eyes, it may cause a
serious injury. To protect your eyes against such accident, it is necessary to always wear goggles.
Should it occur that HFC-134a (R-134a) strikes your eye(s), consult a doctor immediately.
–Do not use your hand to rub the affected eye(s). Instead, use quantities of fresh cold water to
splash it over the affected area to gradually raise temperature of such area above freezing point.
–Obtain proper treatment as soon as possible from a doctor or eye specialist.
Should the HFC-134a (R-134a) liquid come into contact with your skin, the affected area should be
treated in the same manner as when skin is frostbitten or frozen.
Refrigerant must not be handled near where welding or steam cleaning is performed.
Refrigerant should be kept at a cold and dark place. It should never be stored where a high temper-
ature is anticipated, e.g. where exposed to direct sun light, close to fire or inside vehicle (including
trunk room).
Avoid breathing fumes produced when HFC-134a (R-134a) is burned. Such fumes may be hazardous
to health.
Start evacuating
Charge proper amount of refrigerant
in gas form
Amount of refrigerant
Dual A/C model : 750±50g (1.65±0.11 lb, 26.45±1.76 oz)
Single A/C model : 500±50g (1.1±0.11 lb, 17.64±1.76 oz)
Inspect and repair connections Stop evacuating
Performance test
Check system for pressure tightness
Charge A/C with refrigerant
Check system for refrigerant leaks and
refrigerant charging quantity
20 minutes
Wait 10 minutes
If gauge shows abnormal conditions

1B-20 AIR CONDITIONING (OPTIONAL)
Recovery
NOTE:
When discharging refrigerant out of A/C system,
always recover it by using refrigerant recovery and
recycling equipment (1). Discharging it into atmo-
sphere would cause adverse effect to environments.
When handling recovery and recycling equipment, be
sure to follow the instruction manual for the equip-
ment.
1