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.
1B-14 AIR CONDITIONING (OPTIONAL)
Wiring Circuit
ACG
LT GRN
PNK
PNK
BLKORN
BLK
YEL/GRNRED/BLKBLK/WHT
BLU/WHTPNK/BLK
PNK/GRN
RED/BLK
WHT/RED
YEL/GRN
YEL/BLU
A/C
RED/BLU
RED/BLU
RED/BLKBLK
BLU/ORN
BLU/WHT
BLU/WHT
PNK
PNK/BLU
BLK
PNK/WHT
YEL/BLK
GRY/WHT
GRN/BLK
BLK/WHT
RED/BLK
YEL/GRN
BLK
BLK
BLK
YEL/BLK
YEL/GRN
YEL/GRNBLU/GRN
BLU/YELBLUBLU/BLK
BLU/BLK
17
21
22 18
16
15
19
2026 25 24 23
14
12
29
3
4
7
33 30
31
32
28
27
1213
10
11
35 349
856
A
1. Front blower motor main relay 10. Compressor relay 19. Battery 28. Solenoid valve relay
2. Front blower motor 11. Compressor 20. Generator 29. Rear blower motor relay
3. Front blower motor resistor 12. Condenser cooling fan motor
relay21. Ignition main fuse 60 A 30. Rear blower motor resistor
4. Front blower motor switch 13. Condenser cooling fan motor 22. Heater/A/C main fuse 60 A 31. Rear blower motor
5. A/C controller 14. Fuse box 23.“IG METER” fuse 20 A 32. Rear blower motor switch
6. ECM (PCM) 15.“A/C” fuse 25 A 24.“REAR DEFG” fuse 25 A 33. Rear A/C main switch
7. Heater mode control switch 16. Ignition switch 25.“REAR BLOW” fuse 20A 34. Rear A/C evaporator temperature con-
troller
8. Dual (refrigerant) pressure switch 17. Main fuse box 26.“FRONT BLOW” fuse 30A 35. Rear A/C evaporator temperature sensor
9. A/C evaporator thermistor
(A/C evaporator temperature sensor)18. Battery main fuse 100 A 27. Solenoid valve [A] : Rear A/C wiring circuit (if equipped)
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-16 AIR CONDITIONING (OPTIONAL)
SYSTEM CIRCUIT
Terminal arrangement of A/C controller
Terminal arrangement of ECM
A: To “FRONT BLOW” fuse 1. Front blower motor relay 6. Dual (refrigerant) pressure switch 11. Condenser cooling fan motor
B: To “REAR DEFG” fuse 2. Front blower motor 7. A/C thermistor (evaporator temperature sensor) 12. A/C controller
C: To “IG METER” fuse 3. Front blower motor resistor 8. Compressor relay 13. ECM
D: To “A/C” fuse 4. Front blower motor switch 9. Compressor
5. A/C switch 10. Condenser cooling fan motor relay
5V
12V12V
12V5V
12V
5V
AC-A-1
AC-A-7
AC-A-4
AC-B-2
AC-B-1
AC-A-16AC-A-9
AC-A-2 AC-A-13
E61-8
E61-17
E61-22
A
DBBC
1
2
3
4
7 865
1011912
13
12 12
3
45 6 7 8 9 101112131415 16 AC-B
AC-A
87
22 23
34
3565
16 17
25
262
1
8 9
20
212
1
8 9
21
22 1 2 3 4 5 6
9
24 25 26 27 28 29 30 31 32 3310 11
12 13 14 15 16 17 18 19 20 211 2 3 4
7 8 9
10 11 12 13 14 15
18 19 20 21 22 23 243 4 5 6 7
10 11 12 13 14 15 16 17 18 19
22 23 24 25 26
27 283 4 5 6 7
10 11 12 13 14 15 16 19 18 2017
23
24 25 26 27 29 28 30 E61 C51-3 C51-1 C51-2
AIR CONDITIONING (OPTIONAL) 1B-17
A/C CONTROLLER VOLTAGE VALUES TABLE
Terminal Wire CircuitMeasurement
groundNormal value Condition
AC-A-1BLK/
WHTController main
power supplyGround to
engine (Fig B)10 – 14 VIgnition switch ON with engine
stopped
AC-A-2BLK/
YELController main
groundGround to body
(Fig A)–0.4 – 0 V Engine running
AC-A-4 ORNRefrigerant
(dual) pressure
switch inputGround to
engine (Fig B)0 – 1 VRefrigerant pressure within 225
kpa (2.3 kg/cm
2, 32.7 psi) to
2548 kpa (26 kg/cm
2, 370 psi)
with engine running
10 – 14 VRefrigerant pressure below 196
kpa (2.0 kg/cm
2, 28 psi) or above
3140 kpa (32 kg/cm
2, 455 psi)
with engine running
AC-A-7GRN/
BLKA/C switch and/
or defroster
switch inputGround to
engine (Fig B)8 – 14 VBlower fan motor switch or A/C or
defroster switch OFF with engine
running
0 – 1.5 VBlower fan motor switch and A/C
or defroster switch ON with
engine running
AC-A-9GRY/
WHTSignal input from
ECM (A/C ON
permission sig-
nal)Ground to
engine (Fig B)10 – 14 V Approve of A/C ON
0 – 1 V A/C ON forbid
AC-A-13YEL/
BLKSignal output to
ECM (A/C ON
request signal)Ground to
engine (Fig B)0 – 1.5 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)) and
refrigerant pressure switch is ON
10 – 14 VExcept the above-mentioned with
engine running
AC-A-16 PNKCompressor
magnet clutch
relay outputGround to
engine (Fig B)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
10 – 14 VExcept the above-mentioned with
engine running
AC-B-1BLU/
YELSensor groundGround to body
(Fig A)–0.4 – 0 V Engine running