Page 433 of 3171

TROUBLE DIAGNOSIS
ATC-99
C
D
E
F
G
H
I
K
L
MA
B
AT C
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.
lAir conditioning system
does not function and does
not cyclically cool the com-
partment air.
lThe 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.
lDrain water from refrigerant
or replace refrigerant.
lReplace 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¢spipeis
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 malfunction is caused by
water or foreign particles.
lIf water is the cause, initially
cooling is okay. Then the
water freezes causing a
blockage. Drain water from
refrigerant or replace refrig-
erant.
lIf due to foreign particles,
remove expansion valve
and remove the particles
with dry and compressed air
(not shop air).
lIf either of the above meth-
ods cannot correct the mal-
function, replace expansion
valve.
lReplace liquid tank.
lCheck lubricant for contami-
nation.
AC362A
Page 434 of 3171
ATC-100
TROUBLE DIAGNOSIS
Insufficient Heating
EJS006BS
SYMPTOM: Insufficient heating
INSPECTION FLOW
*1ATC-57, "Operational Check".*2AT C - 6 8 , "Air Mix Door Motor Circuit".*3ATC-55, "A/C System Self-diagno-
sis Function".
*4ATC-55, "
A/C System Self-diagnosis
Function".*5AT C - 8 0 , "
Blower Motor Circuit".*6EC-103, "DTC P0117, P0118 ECT
SENSOR".
*7CO-7, "
Changing Engine Coolant".*8CO-13, "Checking Reservoir Tank
Cap".
MJIB0350E
Page 435 of 3171
TROUBLE DIAGNOSIS
ATC-101
C
D
E
F
G
H
I
K
L
MA
B
AT C
NoiseEJS006BT
SYMPTOM: Noise
INSPECTION FLOW
WJIA0473E
Page 436 of 3171
ATC-102
TROUBLE DIAGNOSIS
*1ATC-143, "REMOVAL".*2ATC-144, "INSTALLATION".*3AT C - 2 4 , "Maintenance of Lubricant
Quantity in Compressor".
*4ATC-57, "
Operational Check".*5EM-12, "Checking Drive Belts".
Page 437 of 3171
TROUBLE DIAGNOSIS
ATC-103
C
D
E
F
G
H
I
K
L
MA
B
AT C
Self-diagnosisEJS006BU
SYMPTOM: Self-diagnosis cannot be performed.
INSPECTION FLOW
*1AT C - 6 0 , "Power Supply and Ground
Circuit for Front Air Control".*2ATC-105, "
Ambient Sensor Circuit".*3ATC-108, "In-vehicle Sensor Circuit".
*4AT C - 11 2 , "
Optical Sensor Circuit".*5ATC-114, "Intake Sensor Circuit".*6AT C - 6 8 , "Air Mix Door Motor Circuit".
*7AT C - 5 7 , "
Operational Check".*8ATC-35, "SYMPTOM TABLE".
MJIB0351E
Page 438 of 3171
ATC-104
TROUBLE DIAGNOSIS
Memory Function
EJS006BV
SYMPTOM: Memory function does not operate.
INSPECTION FLOW
*1ATC-60, "Power Supply and Ground
CircuitforFrontAirControl".*2ATC-57, "
Operational Check".*3AT C - 5 5 , "A/C System Self-diagnosis
Function".
MJIB0332E
Page 439 of 3171

TROUBLE DIAGNOSIS
ATC-105
C
D
E
F
G
H
I
K
L
MA
B
AT C
Ambient Sensor CircuitEJS006BW
COMPONENT DESCRIPTION
Ambient Sensor
Ambient sensor is attached to the radiator core support (left side). It
detects ambient temperature and converts it into a resistance value
which is then input into the front air control.
AMBIENT TEMPERATURE INPUT PROCESS
The front air control includes a processing circuit for ambient sensor input. However, when the temperature
detected by ambient sensor increases quickly, the processing circuit retards the front air control function. It
only allows the front air control to recognize an ambient temperature increase of 0.33°C(0.6°F) per 100 sec-
onds.
This prevents constant adjustments due to momentary conditions, such as stopping after high speed driving.
Although the actual ambient temperature has not changed, the temperature detected by ambient sensor will
increase. This is because the heat from the engine compartment can radiate to the front grille area, location of
ambient sensor .
DIAGNOSTIC PROCEDURE FOR AMBIENT SENSOR
SYMPTOM: Ambient sensor circuit is open or shorted. (40 or 41 is
indicated on front air control as a result of conducting the front air
control self-diagnosis)
1.CHECK VOLTAGE BETWEEN AMBIENT SENSOR AND GROUND
1. Disconnect ambient sensor connector.
2. Turn ignition switch ON.
3. Check voltage between ambient sensor harness connector E48
terminal 4 and ground.
OK or NG
OK >> GO TO 2.
NG >> GO TO 4.
MJIB0168E
MJIB0090E
4 - Ground : Approx. 5V
MJIB0091E
Page 440 of 3171

ATC-106
TROUBLE DIAGNOSIS
2.CHECK CIRCUIT CONTINUITY BETWEEN AMBIENT SENSOR AND FRONT AIR CONTROL
1. Turn ignition switch OFF.
2. Disconnect front air control connector.
3. Check continuity between ambient sensor harness connector
E48 terminal 3 and front air control harness connector M60 ter-
minal 13.
OK or NG
OK >> GO TO 3.
NG >> Repair harness or connector.
3.CHECK AMBIENT SENSOR
Refer toATC-107, "
Ambient Sensor".
OK or NG
OK >> 1. Replace front air control.
2. Go to self-diagnosisAT C - 5 5 , "
A/C System Self-diagnosis Function"and perform self-diagno-
sis.
NG >> 1. Replace ambient sensor.
2. Go to self-diagnosisAT C - 5 5 , "
A/C System Self-diagnosis Function"and perform self-diagno-
sis.
4.CHECK CIRCUIT CONTINUITY BETWEEN AMBIENT SENSOR AND FRONT AIR CONTROL
1. Turn ignition switch OFF.
2. Disconnect front air control connector.
3. Check continuity between ambient sensor harness connector
E48 terminal 4 and front air control harness connector M61 ter-
minal 28.
4. Check continuity between ambient sensor harness connector
E48 terminal 4 and ground.
OK or NG
OK >> 1. Replace front air control.
2. Go to self-diagnosisAT C - 5 5 , "
A/C System Self-diagnosis Function"and perform self-diagno-
sis.
NG >> Repair harness or connector.3 - 13 : Continuity should exist.
MJIB0092E
4 - 28 : Continuity should exist.
4 - Ground : Continuity should not exist.
MJIB0093E