2005 MITSUBISHI 380 AC temperature sensor

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-24
STEP 3. Using diagnostic tool , check data list item 20: Air
thermo sensor.
To prevent damage to diagnostic tool , always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting diagnostic tool .
(1) Connect diagnostic tool to the data link connector.
(2) Ignition switch: ON
(3) Set diagnostic tool to the data reading mode for item 20: Air
thermo sensor.
Check that the passenger room temperature matches
the displayed value on the diagnostic tool while the
engine is cold.
NOTE: When this DTC is set and the system is fail-safe sta-
tus, the value of service data displays
6C.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor within the specified range?
YES : Replace the A/C-ECU. Then go to Step 7.
NO : Go to Step 4.

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-27
STEP 6. Check the air thermo sensor.
(1) Disconnect the air thermo sensor connector C-126.
(2) Measure the resistance between connector terminals 1 and
2 under at least two different temperatures. The resistance
values should generally match those in the graph.
NOTE: The temperature at the check should not exceed the
range in the graph.
Q: Is the air thermo sensor in good condition?
YES : Replace the A/C-ECU. Then go to Step 7.
NO : Replace the air thermo sensor. Then go to Step 7.
STEP 7. Recheck for diagnostic trouble code.
Check again if the DTC is set.
(1) Connect diagnostic tool to the data link connector
(2) Turn the ignition switch to the "ON" position.
(3) Check if the DTC is set.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the check result satisfactory?
YES : The procedure is complete.
NO : Return to Step 1.

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-75
INSPECTION PROCEDURE 4: When the A/C is Operating, Temperature Inside the Passenger
Compartment does not Decrease (Cool Air is not Emitted).
.
TECHNICAL DESCRIPTION (COMMENT)
If cool air is not distributed when the A/C switch is on,
the A/C compressor relay system may be defective.
.
TROUBLESHOOTING HINTS
Improper amount of refrigerant
Malfunction of the air thermo sensor
Malfunction of the ambient air temperature sen-
sor
Malfunction of the A/C pressure sensor
Malfunction of the A/C compressor relay
Malfunction of the A/C refrigerant temperature
switch
Malfunction of the air conditioning compressor
clutch
Malfunction of the A/C-ECU
Malfunction of the ECU
Damaged harness wires or connectors
Refer to component locations GROUP-70
Refer to configuration diagrams GROUP-80
Refer to circuit diagrams GROUP-90
DIAGNOSIS
Required Special Tools:
MB991223: Harness Set
: Scan Tool (MUT-III Sub Assembly)

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-87
STEP 18. Check the air conditioning compressor clutch
operation.
Connect the compressor connector terminal to the battery posi-
tive (+) terminal and ground the battery’s negative (-) terminal
to the compressor unit. At that time, the air conditioning com-
pressor clutch should make a definite operating sound.
Q: Can the sound (click) of the air conditioning
compressor clutch operation be heard?
YES : Go to Step 19.
NO : Replace the compressor magnet clutch. Check that
the air conditioning works normally.
STEP 19. Check the air thermo sensor.
Measure the resistance between connector terminals 1 and 2
under at least two different temperatures. The resistance val-
ues should generally match those in the graph.
NOTE: The temperature at the check should not exceed the
range in the graph.
Q: Is the air thermo sensor in good condition?
YES : Go to Step 20.
NO : Replace the air thermo sensor. Check that the air
conditioning works normally.
STEP 20. Check the ambient air temperature sensor.
Measure the resistance between the sensor terminals under at
least two temperatures. The resistance values should meet the
values shown.
NOTE: The temperature should be within the shown range.
Q: Is the ambient air temperature sensor in good
condition?
YES : Go to Step 22.
NO : Replace the ambient air temperature sensor. Check
that the air conditioning works normally.

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-104
INSPECTION PROCEDURE 7: The A/C Indicator Flashes.
.
TECHNICAL DESCRIPTION (COMMENT)
If the A/C indicator flashes, inadequate refrigerant
quantity, the ambient air temperature sensor circuit
or the A/C pressure sensor circuit is suspected.
.
TROUBLESHOOTING HINTS
Malfunction of the A/C pressure sensor
Malfunction of the ambient air temperature sen-
sor
Malfunction of the A/C-ECU
Refer to component locations GROUP-70
Refer to configuration diagrams GROUP-80
Refer to circuit diagrams GROUP-90
DIAGNOSIS
Required Special Tools:
MB991223: Test Harness Set
: Scan Tool (MUT-III Sub Assembly)
MB991824: Vehicle Communication Interface (V.C.I.)
MB991827: MUT-III USB Cable
MB991910: MUT-III Main Harness A (Vehicles with CAN
communication system)
STEP 1. Using scan tool , read the diagnostic trouble code.
Check if an A/C-ECU DTC is set.
(1) Connect scan tool to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Check if the DTC is set.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the check result satisfactory?
YES : Go to Step 2.
NO : Refer to DIAGNOSTIC TROUBLE CODE CHART
P.55-9.

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-128
STEP 9. Check the wiring harness between A/C-ECU
connector C-16 (terminal 27) and the ground.
Q: Is the wiring harness between A/C-ECU connector C-16
(terminal 27) and ground in good condition?
YES : It can be assumed that this malfunction is intermittent.
Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points
How to
Cope with Intermittent Malfunctions P.00-14. check
that the air conditioning works normally.
NO : Repair the wiring harness. Check that the air
conditioning works normally.
INSPECTION PROCEDURE 12: When Sunlight Intensity Changes, Air Outlet Temperature Does Not
Change.
.
CIRCUIT OPERATION
When the blower air temperature cannot be changed
even if the preset temperature is changed, the sen-
sors may be defective.
.
TROUBLESHOOTING HINTS
Improper amount of refrigerant
Malfunction of the A/C pressure sensor
Malfunction of the photo sensor
Malfunction of the A/C-ECU
The wiring harness or connectors may have
loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector.
Refer to component locations GROUP-70
Refer to configuration diagrams GROUP-80
Refer to circuit diagrams GROUP-90

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-133
DATA LIST REFERENCE TABLEM1554005100136
MUT-III
DIAGNOSTIC
TOOL DISPLAYITEM
NO.INSPECTION ITEM INSPECTION REQUIREMENT NORMAL VALUE
Inside
temperature
sensor59 Interior temperature
sensorIgnition switch: ON Inside air
temperature and
temperature
displayed on the
diagnostic tool are
identical.
Outside
temperature
sensor58 Outside temperature
sensorIgnition switch: ON Outside air
temperature and
temperature
displayed on the
diagnostic tool are
identical.
Air thermo sensor 20 Air thermo sensor Ignition switch: ON The temperature
measured behind
the evaporator
matches the
displayed value on
the diagnostic tool
while the engine is
cold.
Pressure sensor 61 A/C pressure sensor Ignition switch: ON Measured refrigerant
pressure is nearly
equal to the value
shown on the
diagnostic tool
(MPa).
Water
temperature
sensor62 Engine coolant
temperature sensor
(Data received by
CAN
Communication)Ignition switch: ON Engine coolant
temperature and
temperature
displayed on the
diagnostic tool are
identical.
Photo sensor 67 Photo sensor Ignition switch: ON Amount of light is
proportional to
voltage displayed on
the diagnostic tool.
Air mix
potentiometer63 Air mixing damper
control motor
potentiometerIgnition switch: ON Damper
positionOpening degree (V)
MAX. HOT Approx. 5
MAX. COOL Approx. 0
Air mix
potentiometer
(Target)64 Target value for air
mixing damper
control motor
potentiometerIgnition switch: ON Damper
positionOpening degree (V)
MAX. HOT Approx. 5
MAX. COOL Approx. 0

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-138
16 Potentiometer power supply Ignition switch: ON 5 V
17 Power transistor (BASE) When the blower speed
selection dial shows Maximum
air volume.1 V
18 Power transistor
(COLLECTOR)When the blower speed
selection dial shows Maximum
air volume.12.1 V
19 Photo sensor Ignition switch: ON 5 V
20 Sensors and potentiometers
groundAlways 0 V
21 Mode selection damper control
motor potentiometer inputWhen the damper is moved to
the FACE position. 4 V
22 Interior temperature sensor Ignition switch: ON 5 V
23 Ambient temperature sensor
inputWhen sensor temperature is
25
C (77F) [4 k]1.9 V
24 Air thermo sensor input When sensor temperature is
25
C (77F) [1.5 k]2.2 V
25 Photo sensor ground Ignition switch: ON 0 V
26 A/C pressure sensor at 2.6 MPa 3.9 V
27 Ground Always 0 V
28 Power supply to the ignition
switch (IG2)Ignition switch: ON Battery positive voltage
29 Air mixing damper control motor
potentiometer inputWhen the damper door is
moved to the MAX. HOT
position.1.4 V
30 Illumination ground Always 0 V
31 ILL power supply Lighting switch: ON Battery positive voltage
34 A/C pressure sensor ground Always 0 V
36 Power supply to the ignition
switch (ACC)Ignition switch: ON Battery positive voltage TERMINAL
NO.CHECK ITEM CHECKING REQUIREMENTS NORMAL CONDITION