Page 2043 of 3189
TROUBLE DIAGNOSIS
ATC-63
C
D
E
F
G
H
I
K
L
MA
B
AT C
Air Mix Door Motor CircuitEJS001ZM
SYMPTOM:
●Discharge air temperature does not change.
●Air mix door motor does not operate.
INSPECTION FLOW
*1AT C - 4 2 , "Self-diagnosis Function",
see No.1*2ATC-100, "Ambient Sensor Circuit"*3ATC-102, "In-vehicle Sensor Circuit"
*4ATC-105, "Sunload Sensor Circuit"*5AT C - 6 3 , "Air Mix Door Motor Cir-
cuit"
*6AT C - 4 2 , "Self-diagnosis Function",
see No. 14.
*7AT C - 5 7 , "
LAN System Circuit"*8AT C - 5 1 , "Operational Check"*9AT C - 5 1 , "Operational Check"
*10AT C - 2 9 , "SYMPTOM TABLE"*11ATC-108, "Intake Sensor Circuit"*12AT C - 4 2 , "Self-diagnosis Function",
see No. 7
RJIA1694E
Page 2046 of 3189
ATC-66
TROUBLE DIAGNOSIS
Intake Door Motor Circuit
EJS001ZN
SYMPTOM:
●Intake door does not change.
●Intake door motor does not operate normally.
INSPECTION FLOW
*1 AT C - 4 2 , "Self-diagnosis Function" ,
see No.1*2ATC-100, "Ambient Sensor Circuit"*3AT C - 1 0 2 , "In-vehicle Sensor Circuit"
*4ATC-105, "Sunload Sensor Circuit"*5ATC-63, "Air Mix Door Motor Circuit"*6AT C - 4 2 , "Self-diagnosis Function",
see No. 14.
*7AT C - 5 7 , "
LAN System Circuit"*8ATC-67, "COMPONENT DESCRIP-
TION"
*9AT C - 5 1 , "Operational Check"
RJIA1695E
Page 2049 of 3189
TROUBLE DIAGNOSIS
ATC-69
C
D
E
F
G
H
I
K
L
MA
B
AT C
Blower Motor CircuitEJS001ZO
SYMPTOM:
●Blower motor operation is malfunctioning.
●Blower motor operation is malfunctioning under out of starting fan speed control.
INSPECTION FLOW
RJIA1696E
Page 2055 of 3189
TROUBLE DIAGNOSIS
ATC-75
C
D
E
F
G
H
I
K
L
MA
B
AT C
Magnet Clutch CircuitEJS001ZP
SYMPTOM: Magnet clutch does not engage.
INSPECTION FLOW
*1ATC-42, "Self-diagnosis Function",
see No.1.*2ATC-100, "Ambient Sensor Circuit"*3ATC-102, "In-vehicle Sensor Circuit"
*4ATC-105, "Sunload Sensor Circuit"*5AT C - 6 3 , "Air Mix Door Motor Circuit"*6ATC-42, "Self-diagnosis Function",
see No. 14.
*7ATC-75, "
Magnet Clutch Circuit"*8AT C - 9 2 , "TROUBLE DIAGNOSES
FOR UNUSUAL PRESSURE"
*9ATC-51, "Operational Check"
*10ATC-42, "Self-diagnosis Function"
see No.5 or 7.*11AT C - 2 9 , "
SYMPTOM TABLE"*12ATC-108, "Intake Sensor Circuit"
RJIA1697E
Page 2066 of 3189
ATC-86
TROUBLE DIAGNOSIS
Insufficient Cooling
EJS001ZQ
SYMPTOM: Insufficient cooling
INSPECTION FLOW
*1ATC-42, "Self-diagnosis Function",
see No.1.*2ATC-63, "Air Mix Door Motor Circuit"*3ATC-90, "Test Reading (Gasoline
Engine)"
ATC-90, "Test Reading (Diesel
Engine)"
*4ATC-42, "Self-diagnosis Function",
see No.14.*5ATC-57, "LAN System Circuit"*6ATC-69, "Blower Motor Circuit"
RJIA1708E
Page 2072 of 3189

ATC-92
TROUBLE DIAGNOSIS
TROUBLE DIAGNOSES FOR UNUSUAL PRESSURE
Whenever system′s high and/or low side pressure is unusual, diagnose using a manifold gauge. The marker
above the gauge scale in the following tables indicates the standard (usual) pressure range. Since the stan-
dard (usual) pressure, however, differs from vehicle to vehicle, refer to above table (Ambient air temperature-
to-operating pressure table).
Both High and Low-pressure Sides are Too High.
High-pressure Side is Too High and Low-pressure Side is Too Low.
Gauge indication Refrigerant cycle Probable cause Corrective action
Both high and low-pressure sides
are too high.Pressure is reduced soon
after water is splashed on
condenser.Excessive refrigerant charge in
refrigeration cycleReduce refrigerant until spec-
ified pressure is obtained.
Air suction by cooling fan is
insufficient.Insufficient condenser cooling
performance
↓
1. Condenser fins are clogged.
2. Improper fan rotation of cool-
ing fan
●Clean condenser.
●Check and repair cooling
fan as necessary.
●Low-pressure pipe is not
cold.
●When compressor is
stopped high-pressure
value quickly drops by
approximately 196 kPa
(1.96 bar, 2 kg/cm
2 , 28
psi). It then decreases
gradually thereafter.Poor heat exchange in con-
denser
(After compressor operation
stops, high pressure decreases
too slowly.)
↓
Air in refrigeration cycleEvacuate repeatedly and
recharge system.
Engine tends to overheat.Engine cooling systems mal-
function.Check and repair each
engine cooling system.
●An area of the low-pres-
sure pipe is colder than
areas near the evaporator
outlet.
●Plates are sometimes cov-
ered with frost.
●Excessive liquid refrigerant
on low-pressure side
●Excessive refrigerant dis-
charge flow
●Expansion valve is open a lit-
tle compared with the specifi-
cation.
↓
1. Improper expansion valve
installation
2. Improper expansion valve
adjustmentReplace expansion valve.
AC359A
Gauge indication Refrigerant cycle Probable cause Corrective action
High-pressure side is too high and
low-pressure side is too low.
Upper side of condenser and
high-pressure side are hot,
however, liquid tank is not so
hot.High-pressure tube or parts
located between compressor
and condenser are clogged or
crushed.
●Check and repair or replace
malfunctioning parts.
●Check lubricant for contami-
nation.
AC360A
Page 2073 of 3189

TROUBLE DIAGNOSIS
ATC-93
C
D
E
F
G
H
I
K
L
MA
B
AT C
High-pressure Side is Too Low and Low-pressure Side is Too High.
Both High- and Low-pressure Sides are Too Low.
Gauge indication Refrigerant cycle Probable cause Corrective action
High-pressure side is too low and
low-pressure side is too high.High and low-pressure sides
become equal soon after com-
pressor operation stops.Compressor pressure opera-
tion is improper.
↓
Damaged inside compressor
packingsReplace compressor.
No temperature difference
between high and low-pres-
sure sidesCompressor pressure opera-
tion is improper.
↓
Damaged inside compressor
packings.Replace compressor.
AC356A
Gauge indication Refrigerant cycle Probable cause Corrective action
Both high- and low-pressure sides
are too low.
●There is a big temperature
difference between receiver
drier outlet and inlet. Outlet
temperature is extremely
low.
●Liquid tank inlet and expan-
sion valve are frosted.Liquid tank inside is slightly
clogged.
●Replace liquid tank.
●Check lubricant for contami-
nation.
●Temperature of expansion
valve inlet is extremely low
as compared with areas
near liquid tank.
●Expansion valve inlet may
be frosted.
●Temperature difference
occurs somewhere in high-
pressure sideHigh-pressure pipe located
between receiver drier and
expansion valve is clogged.
●Check and repair malfunc-
tioning parts.
●Check lubricant for contami-
nation.
Expansion valve and liquid
tank are warm or only cool
when touched.Low refrigerant charge
↓
Leaking fittings or componentsRefer to ATC-145, "
Checking
for Refrigerant Leaks" .
There is a big temperature dif-
ference between expansion
valve inlet and outlet while the
valve itself is frosted.Expansion valve closes a little
compared with the specifica-
tion.
↓
1. Improper expansion valve
adjustment
2. Malfunctioning expansion
valve
3. Outlet and inlet may be
clogged.
●Remove foreign particles by
using compressed air.
●Check lubricant for contami-
nation.
An area of the low-pressure
pipe is colder than areas near
the evaporator outlet.Low-pressure pipe is clogged
or crushed.
●Check and repair malfunc-
tioning parts.
●Check lubricant for contami-
nation.
Air flow volume is not enough
or is too low.Evaporator is frozen.
●Check intake sensor circuit.
Refer to AT C - 1 0 8 , "
Intake
Sensor Circuit"
●Replace compressor.
AC353A
Page 2074 of 3189

ATC-94
TROUBLE DIAGNOSIS
Low-pressure Side Sometimes Becomes Negative.
Low-pressure Side Becomes Negative.
Gauge indication Refrigerant cycle Probable cause Corrective action
Low-pressure side sometimes
becomes negative.
●Air conditioning system
does not function and does
not cyclically cool the com-
partment air.
●The system constantly func-
tions for a certain period of
time after compressor is
stopped and restarted.Refrigerant does not dis-
charge cyclically.
↓
Moisture is frozen at expan-
sion valve outlet and inlet.
↓
Water is mixed with refriger-
ant.
●Drain water from refrigerant
or replace refrigerant.
●Replace liquid tank.
AC354A
Gauge indication Refrigerant cycle Probable cause Corrective action
Low-pressure side becomes nega-
tive.
Liquid tank or front/rear side of
expansion valve′s pipe is
frosted or dewed.High-pressure side is closed
and refrigerant does not flow.
↓
Expansion valve or liquid tank
is frosted.Leave the system at rest until
no frost is present. Start it
again to check whether or not
the problem is caused by
water or foreign particles.
●If water is the cause, initially
cooling is okay. Then the
water freezes causing a
blockage. Drain water from
refrigerant or replace refrig-
erant.
●If due to foreign particles,
remove expansion valve
and remove the particles
with dry and compressed air
(not shop air).
●If either of the above meth-
ods cannot correct the prob-
lem, replace expansion
valve.
●Replace liquid tank.
●Check lubricant for contami-
nation.
AC362A