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-25
On-Vehicle Service
Precaution
When servicing air conditioning system, the following rules must be observed.
Piping
When connecting hoses and pipes, apply a few drops of compressor oil (refrigerant oil) to seats of coupling
nuts and O-ring. WARNING:
Should refrigerant HFC-134a (R-134a) strike your eye(s), consult a doctor immediately.
DO NOT USE YOUR HAND TO RUB AFFECTED EYE(S).
Instead, use quantities of fresh cold water to splash it over affected area to thus gradually raise its
temperature above the freezing point.
Obtain proper treatment as soon as possible from a doctor or eye specialist.
Should liquid refrigerant HFC-134a (R-134a) get on your skin, such affected part should be treated
in the same manner as when skin is frostbitten or frozen.
CAUTION:
None of refrigerant, compressor oil and component parts is interchangeable between two types of
A/C: one using CFC-12 (R-12) and the other using HFC-134a (R-134a).
(For identification between these two types, refer to “REFRIGERANT TYPE” in this section.
When replenishing or changing refrigerant and compressor oil and when replacing parts, make sure
that the material or the part to be used is appropriate to the A/C installed in the vehicle being serviced.
Use of incorrect one will result in leakage of refrigerant, damage in parts or other faulty condition.
NOTE:
Single A/C model is the same as SQ625 (H25 engine) model. Refer to the same section of the Service
Manual mentioned in FOREWORD of this manual.
[A]: Dual A/C model 1. Suction hose 4. Condenser outlet pipe 7. Front suction pipe
Apply compressor oil (refrigerant oil) to O-ring. 2. Discharge hose 5. Expansion valve 8. Rear liquid pipe
3. Front liquid pipe 6. Dual (refrigerant) pressure switch 9. Rear suction pipe
1
6 43 75
9
8
2 [A]
AIR CONDITIONING (OPTIONAL) 1B-27
Replenishing compressor oil
When replacing air conditioning parts with new ones, it is neces-
sary to replenish oil by the amount supposedly remaining in each
part.
WHEN CHANGING GAS ONLY
When it is unavoidable to change gas without replacing any com-
ponent part for engine removal and installation or for some other
reason, replenish 20 cm
3 (20cc) oil. When replenishing gas only,
oil replenishment is not necessary.
WHEN REPLACING COMPRESSOR
Compressor oil is sealed in each new compressor by the amount
required for air conditioner cycle. Therefore, when using a new
compressor for replacement, drain oil from it by the amount calcu-
lated as follows.
“C” = “A” – “B”
“C” : Amount of oil to be drained
“A” : Amount of oil sealed in a new compressor
“B” : Amount of oil remaining in removed compressor
Amount of oil in new compressor :
Dual A/C model 140 cm
3 (140 cc)
Single A/C model 100 cm
3 (100 cc)
WHEN REPLACING OTHER PART
Amount of compressor oil : CAUTION:
Be sure to use HFC-134a (R-134a) compressor oil.
NOTE:
Compressor assembly supplied from factory is filled up
with the following amount of oil.
Replaced part Amount of compressor oil
to be replenished
Evaporator
25 cm
3 (25 cc)
Rear evaporator
(for dual A/C model)25 cm
3 (25 cc)
Condenser
15 cm
3 (15 cc)
Receiver/dryer
20 cm
3 (20 cc)
Hoses
10 cm
3 (10 cc) each
Pipes
10 cm
3 (10 cc) each
1. New compressor
2. Removed compressor
3. Excess oil (A–B)
1B-38 AIR CONDITIONING (OPTIONAL)
Compressor Assembly
INSPECTION
1) Install manifold gauge set (1) as shown in the figure.
2) Close Hi (4) and Lo (5) side valves.
3) Run engine at fast idle.
4) Check compressor for the following items.
If any of the above checks indicated a defect, repair com-
pressor.
High pressure gauge reading is not low and low pressure
gauge reading is not higher than normal.
Metallic sound.
Leakage from compressor. CAUTION:
None of refrigerant, compressor oil and component parts is interchangeable between two types of
A/C: one using CFC-12 (R-12) and the other using HFC-134a (R-134a).
For identification between these two types, refer to page 66.
When replenishing or changing refrigerant and compressor oil and when replacing parts, make sure
that the material or the part to be used is appropriate to the A/C installed in the vehicle being serviced.
Use of incorrect refrigerant or compressor oil will result in leakage of refrigerant, damage in parts or
other faulty condition.
When servicing the compressor, keep dirt or foreign material away from getting on or into the com-
pressor parts and system. Clean tools and a clean work area are important for proper service.
The compressor connection and the outside of the compressor should be cleaned before any “On-
vehicle” repair or before removal of the compressor. The parts must be kept clean at all times and any
parts to be reassembled should be cleaned with Trichloromethane, naphtha, kerosene or equivalent
solvent and dried with dry air. Use only lint free cloths to wipe parts.
The operations described are based on bench overhaul with compressor removed from the vehicle,
except as noted. They have been prepared in order of accessibility of the components.
When compressor is removed from the vehicle for servicing, the oil remaining in the compressor
should be discarded and new refrigerant oil added to the compressor.
Minor repair procedures may be done on the vehicle without discharging the system. Major repair pro-
cedures require that the system be discharged of refrigerant.
2. High pressure side (Delivery side hose)
3. Low pressure side (Suction side pipe)
1
4 5
2
3
AIR CONDITIONING (OPTIONAL) 1B-39
REMOVAL
1) Run engine at idle with A/C ON for 10 minutes.
2) Disconnect negative (–) cable at battery.
3) Recover refrigerant from refrigeration system using recovery
and recycling equipment.
4) Remove P/S pump referring to step 4) to 7) of “REMOVAL”
under “P/S PUMP” in Section 3B1.
5) Disconnect magnet clutch connector.
6) Disconnect suction hose (1) and discharge hose (2) from
compressor.
7) Remove compressor (1) from its mount (2).NOTE:
The amount of compressor oil at removed must be mea-
sured and the same amount must be poured when install-
ing the compressor.
NOTE:
It is not necessary to drain P/S fluid.
NOTE:
Cap open fitting immediately to keep moisture out of sys-
tem.
2
1
NOTE:
If compressor assembly is replaced. Drain oil from com-
pressor, and measure its amount.
1 2
POWER STEERING (P/S) SYSTEM 3B1-3
Hydraulic Pressure in P/S Circuit
Hydraulic pressure check
1) After cleaning joint of high pressure hose and P/S pump
thoroughly, disconnect hose from pump and install special
tool (oil pressure gauge, attachment and hose).
Special tool
(A) : 09915-77410
(B) : 09915-77420
2) Check each connection for fluid leakage and bleed air.
Refer to “AIR BLEEDING PROCEDURE” in this section.
3) With engine idling, turn steering wheel and warm up engine
till temperature of fluid in P/S fluid reservoir rises to 50 –
60°C (122 – 140°F).
4) Check back pressure by measuring hydraulic pressure with
engine idling and hands off steering wheel.
When back pressure is higher than specified values, check
control valve and piping for clogging.
Back pressure :
Lower than 1000 kPa (10 kg/cm
2, 142 psi) CAUTION:
Take care not to cause damage to A/C condenser during
service operation, if equipped.
1. P/S fluid reservoir
2. Attachment
3. Gasket
4. Union bolt
5. High pressure side
6. Low pressure side
1. P/S fluid reservoir 4. P/S gear box
2. Gauge valve (open) 5. High pressure side
3. P/S pump 6. Low pressure side
3B1-4 POWER STEERING (P/S) SYSTEM
5) Check relief pressure.
a) Increase engine speed to about 1500 r/min (rpm). Close
gauge valve gradually while watching pressure increase
indicated by gauge and take reading of relief pressure
(maximum hydraulic pressure).
When it is higher than specified values, possible cause is
malfunction of relief valve.
When it is lower than specified values, possible cause is
either failure of P/S pump or settling of relief valve spring.
Relief pressure (when gauge valve is closed) :
7650 – 8350 kPa (76.5 – 83.5 kg/cm
2, 1088 – 1187 psi)
b) Next, open gauge valve fully and increase engine speed to
about 1500 r/min (rpm). Then turn steering wheel to the left
or right fully and take reading of relief pressure.
When it is higher than specified values, possible cause is
malfunction of relief valve.
When it is lower than specified values, possible cause is
failure in steering gear box. Replace gear box.
Relief pressure (when gauge valve is opened) :
7650– 8350 kPa (76.5 – 83.5 kg/cm
2, 1088 – 1187 psi) CAUTION:
Be sure not to close gauge valve for longer than 10 sec-
onds.
1. P/S fluid reservoir
2. Gauge valve (shut)
3. Oil pressure gauge
4. P/S pump
5. P/S gear box
CAUTION:
Be sure not to hold steering wheel at fully turned position
for longer than 10 seconds.
1. P/S fluid reservoir
2. Gauge valve (open)
3. Oil pressure gauge
4. P/S pump
5. P/S gear box