1B-2 AIR CONDITIONING (OPTIONAL)
REMOVING MANIFOLD GAUGE SET ...... 1B-26
LEAK TEST................................................ 1B-26
LIQUID LEAK DETECTORS .................. 1B-26
ON-VEHICLE SERVICE ................................ 1B-27
SERVICE PRECAUTION........................... 1B-27
REFRIGERANT LINE ............................ 1B-27
HANDLING REFRIGERANT HFC-134a
(R-134a) ................................................. 1B-28
REFRIGERANT RECOVERY ................ 1B-28
REFRIGERANT CHARGE ..................... 1B-28
CONDENSER ASSEMBLY........................ 1B-28
RECEIVER/DRYER ................................... 1B-30
RADIATOR/CONDENSER COOLING FAN
MOTOR...................................................... 1B-31COOLING UNIT (EVAPORATOR) ............ 1B-32
A/C EVAPORATOR TEMPERATURE
SENSOR.................................................... 1B-34
EXPANSION VALVE ................................. 1B-34
A/C REFRIGERANT PRESSURE
SWITCH..................................................... 1B-35
A/C SWITCH.............................................. 1B-36
RADIATOR/CONDENSER COOLING FAN
MOTOR RELAY No.1, No.2 and No.3 ....... 1B-36
COMPRESSOR ......................................... 1B-36
MAGNET CLUTCH .................................... 1B-38
LIP TYPE SEAL ......................................... 1B-41
REQUIRED SERVICE MATERIAL ............... 1B-43
SPECIAL TOOL ............................................ 1B-44
AIR CONDITIONING (OPTIONAL) 1B-3
GENERAL DESCRIPTION
REFRIGERANT CIRCULATION
REFRIGERANT TYPE
Whether the A/C in the vehicle being serviced uses HFC-134a
(R-134a) or CFC-12 (R-12) is indicated on compressor label (1).
Also, it can be checked by the shape of the service (charge) valve
(2).
1. Compressor 4. Receiver/dryer 7. Evaporator
2. Magnet clutch 5. A/C refrigerant pressure switch
3. Condenser assembly 6. Expansion valve
AIR CONDITIONING (OPTIONAL) 1B-5
DIAGNOSIS
GENERAL DIAGNOSIS TABLE
Condition Possible Cause Correction
Cool air won’t come
out (A/C system won’t
operative)No refrigerant Perform recover, evacuation and charging.
Fuse blown Check fuses in circuit fuse and main fuse
boxes, and check short circuit to ground.
A/C switch faulty Check A/C switch.
Blower fan switch faulty Check blower fan switch referring to Sec-
tion 1A.
A/C evaporator temperature sensor
faultyCheck A/C evaporator temperature sen-
sor.
A/C refrigerant pressure switch faulty Check A/C refrigerant pressure switch.
Wiring or grounding faulty Repair as necessary.
ECT sensor faulty Check ECT sensor referring to Section
6E1.
ECM and its circuit faulty Check ECM and its circuit referring to Sec-
tion 6E1.
Cool air won’t come
out (A/C compressor
won’t operative)ECM faulty Check ECM and its circuit referring to Sec-
tion 6E1.
Magnet clutch faulty Check magnet clutch.
Compressor drive belt loosen or broken Adjust or replace drive belt.
Compressor faulty Check compressor.
Compressor thermal switch faulty Check compressor thermal switch
Cool air won’t come
out (A/C condenser
cooling fan motor
won’t operative)Fuse blown Check fuses in circuit fuse and main fuse
boxes, and check short circuit to ground.
Wiring or grounding faulty Repair as necessary.
Radiator/condenser cooling fan motor
relay faultyCheck radiator/condenser cooling fan
motor relay No.1, No.2 and No.3.
Radiator/condenser cooling fan motor
faultyCheck radiator/condenser cooling fan
motor.
ECM faulty Check ECM and its circuit referring to Sec-
tion 6E1.
Cool air won’t come
out (Blower fan motor
won’t operative)Fuse blown Check “HTR” fuse in circuit fuse box and
main fuses, and check short circuit to
ground.
Blower fan motor resistor faulty Check blower fan motor resistor to Section
1A.
Blower fan switch faulty Check blower fan switch referring to Sec-
tion 1A.
Wiring or grounding faulty Repair as necessary.
Blower fan motor faulty Check blower fan motor referring to Sec-
tion 1A.
1B-6 AIR CONDITIONING (OPTIONAL)
Cool air won’t come
out or insufficient
cooling (A/C system
normal operative)Insufficient or excessive charge of
refrigerantCheck charge of refrigerant and system for
leaks.
Condenser clogged Check condenser.
A/C evaporator clogged or frosted Check A/C evaporator and A/C evaporator
temperature sensor.
A/C evaporator temperature sensor
faultyCheck A/C evaporator temperature sen-
sor.
Expansion valve faulty Check expansion valve.
Receiver/dryer clogged Check receiver/dryer.
Compressor drive belt loosen or broken Adjust or replace drive belt.
Magnetic clutch faulty Check magnetic clutch.
Compressor faulty Check compressor.
Air in A/C system Replace dryer, and perform evacuation
and charging.
Air leaking from cooling unit or air duct Repair as necessary.
Heater and ventilation system faulty Check air inlet box (cooling unit), heater
control assembly and heater unit referring
to Section 1A.
Blower fan motor faulty Check blower fan motor referring to Sec-
tion 1A.
Excessive compressor oil existing in A/
C systemPull out compressor oil in A/C system cir-
cuit, and check compressor.
Cool air won’t come
out only intermittentlyWiring connection faulty Repair as necessary.
Expansion valve faulty Check expansion valve.
Excessive moisture in A/C system Replace dryer, and perform evacuation
and charging.
Magnetic clutch faulty Check magnetic clutch.
Excessive charge of refrigerant Check charge of refrigerant.
Cool air comes out
only at high speedCondenser clogged Check condenser.
Insufficient charge of refrigerant Check charge of refrigerant.
Air in A/C system Replace dryer, and perform evacuation
and charging.
Compressor drive belt loosen or broken Adjust or replace drive belt.
Compressor faulty Check compressor.
Cool air won’t come
out only at high speedExcessive charge of refrigerant Check charge of refrigerant.
A/C evaporator frosted Check A/C evaporator and A/C evaporator
temperature sensor.
Insufficient velocity of
cooled airA/C evaporator clogged or frosted Check A/C evaporator and A/C evaporator
temperature sensor.
Air leaking from cooling unit or air duct Repair as necessary.
Blower fan motor faulty Check blower fan motor referring to Sec-
tion 1A.
Wiring or grounding faulty Repair as necessary. Condition Possible Cause Correction
1B-8 AIR CONDITIONING (OPTIONAL)
ABNORMAL NOISE FROM CRANKSHAFT PULLEY
ABNORMAL NOISE FROM TENSION PULLEY
ABNORMAL NOISE FROM A/C EVAPORATOR
ABNORMAL NOISE FROM BLOWER FAN MOTOR
Condition Possible Cause Correction
A large rattling noise
is heard at idle or sud-
den acceleration.Loosen crankshaft pulley bolt Retighten bolt.
Condition Possible Cause Correction
Clattering noise is
heard from pulley.Worn or damaged bearing Replace tension pulley.
Pulley cranks upon
contact.Cracked or loose bracket Replace or retighten bracket.
Condition Possible Cause Correction
Whistling sound is
heard from A/C evapo-
rator.Depending on the combination of the interior/
exterior temperatures, engine rpm and refriger-
ant pressure, the refrigerant flowing out of the
expansion valve may, under certain conditions,
make a whistling soundAt times, slightly decreasing refrig-
erant volume may stop this noise.
Inspect expansion valve and
replace if faulty.
Condition Possible Cause Correction
Blower fan motor
emits a chirping
sound in proportion to
its speed of rotation.Worn or damaged motor brushes or commuta-
torRepair or replace blower fan motor.
Fluttering noise or
large droning noise is
heard from blower fan
motor.Leaves or other debris introduced from fresh air
inlet to blower fan motorRemove debris and make sure that
the screen at fresh air inlet is intact.
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 set (3) are firmly closed.
3) Connect high pressure charging hose (4) to high pressure
service valve (5), and connect low pressure charging hose
(6) to low pressure service valve (7).
4) Bleed the air in charging hoses (4), (6) by loosening their
respective nuts on manifold gauge set (3), utilizing the refrig-
erant pressure. When a hissing sound 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. (Radiator cooling fan should not be
working when checking pressure and temperature.)
6) Turn A/C switch to ON position, and set blower fan switch at
“H” (4th position), temperature dial at “COOL”, air outlet con-
trol dial at “FACE” and fresh/recirculation control dial at
“RECIRCULATION”. (Confirm that A/C compressor and radi-
ator/condenser cooling fan are working.)
Keep all windows, doors and engine food open.
Performance diagnosis condition
7) With dry bulb thermometer (1) inserted into center duct air
outlet and another one set near evaporator air inlet, read
temperature indicated on each thermometer. CAUTION:
Do not interchange high and low pressure charging
hoses by mistake.
Ambient temperature 15 – 35°C (59 – 95°F)
Engine rpm Keep to 1,500 rpm.
Blower fan switch“H” (4th position)
Temperature control“Cool”
Air outlet control“Face”
Vehicle Doors All open
Air inlet door position Recirculation
AIR CONDITIONING (OPTIONAL) 1B-11
8) 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”.
Low side and high side pressure example :
9) Check inlet port temperature-to-outlet port temperature rela-
tionship using graph.
For example, if evaporator inlet port temperature is 25°C
(75°F) and center duct air outlet temperature is 8°C (46°F),
their crossing point is within acceptable range as shown in
graph.
If crossing point is out of acceptable range, diagnose trouble
referring to “PERFORMANCE DIAGNOSIS TABLE”. NOTE:
Pressure registered on gauge varies with ambient tem-
perature. Therefore, use the graphs when determining if
pressures are normal or not.
Gauges should read as follows when ambient tempera-
ture is 30°C (86°F).
Pressure
on high pressure gauge1400 – 1750 kPa
14.0 – 17.5 kg/cm
2
199.1 – 248.9 psi
Pressure
on low pressure gauge230 – 350 kPa
2.3 – 3.5 kg/cm
2
32.7 – 49.8 psi
1B-12 AIR CONDITIONING (OPTIONAL)
PERFORMANCE DIAGNOSIS TABLE
HIGH PRESSURE GAUGE
LOW PRESSURE GAUGE
THERMOMETER AT CENTER DUCT
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 “PER-
FORMANCE DIAGNOSIS” in this section.
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.
Radiator/condenser cooling fan malfunction (Insufficient
cooling of condenser)Check radiator/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 referring to
Section 6B.
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 door in cooling
(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.