MITSUBISHI 380 2005 Workshop Manual

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-10
DIAGNOSTIC TROUBLE CODE PROCEDURES
DTC B1001, B1002: Interior Temperature Sensor System.
DTC SET CONDITION
DTC B1001 is set if there is a short circuit in the
interior temperature sensor input circuit.
DTC B1002 is set if there is a defective connector
connection, or if there is an open circuit in the
harness.
.
TECHNICAL DESCRIPTION (COMMENT)
Current trouble
The A/C-ECU, the interior air temperature sensor,
or connector(s) or wiring between the two may be
defective.Past trouble
If DTC B1001 or B1002 is stored as a past trou-
ble, carry out diagnosis with particular emphasis
on wiring and connector(s) between the A/C-ECU
and the interior air temperature sensor. If the con-
nectors and wiring are normal, and obviously the
ECU is the cause of the trouble, replace the ECU.
If in doubt, do not replace the ECU.
.
TROUBLESHOOTING HINT
Malfunction of connector.
Malfunction of the harness.
Malfunction of the interior temperature sensor.
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 Tool:
: Diagnostic 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)

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-11
STEP 1. Using diagnostic tool , diagnose the CAN bus line.
Use diagnostic tool to diagnose the CAN bus lines.
(1) Connect diagnostic tool to the data link connector.
(2) Turn the ignition switch to "ON" position.
(3) Diagnose the CAN bus line.
Q: Is the check result satisfactory?
YES : Go to Step 2.
NO : Repair the CAN bus lines. (Refer to GROUP 54C,
Diagnosis-CAN Bus Diagnostic Chart P.54C-405).
Then go to Step 7.
STEP 2. Recheck for diagnostic trouble code.
Recheck if the DTC is set.
(1) Erase the DTC.
(2) Turn the ignition switch to "ON" position.
(3) Check if the DTC is set.
Q: Is the check result satisfactory?
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.
NO : Go to Step 3.

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-12
STEP 3. Using diagnostic tool , check data list item 59:
Inside temperature 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) Start the engine.
(3) Set diagnostic tool to the data reading mode for item 59:
Inside temperature sensor.
Check that the interior temperature matches the dis-
played value on the diagnostic tool.
NOTE: When this DTC is set and the system is in fail-safe
status, the value of service data displays 25
C.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Does the interior temperature match the displayed value
on the diagnostic tool?
YES : Replace the A/C-ECU. Then go to Step 7.
NO : Go to Step 4.

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-13
STEP 4. Check A/C-ECU connector C-15, C-16 and interior
temperature sensor connector C-123 for loose, corroded
or damaged terminals, or terminals pushed back in the
connector.
Q: Are A/C-ECU connectors C-15, C-16 and interior
temperature sensor connector C-123 in good condition?
YES : Go to Step 5.
NO : Repair or replace the connector. Refer to GROUP
00E, Harness Connector Inspection P.00E-2. Then go
to Step 7.

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-14
STEP 5. Check the wiring harness between A/C-ECU
connector C-15 (terminals 20), C-16 (terminals 22) and
interior temperature sensor connector C-123 (terminals 1
and 2).
Q: Are the wiring harnesses between A/C-ECU connector
C-15 (terminals 20), C-16 (terminals 22) and interior
temperature sensor connector C-123 (terminals 1 and 2)
in good condition?
YES : Go to Step 6.
NO : Repair the wiring harness. Then go to Step 7.

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-15
STEP 6. Check the interior temperature sensor.
(1) Disconnect interior temperature sensor connector C-123.
(2) When the resistance between the sensor terminals is
measured under two or more temperature conditions, the
resistance should approximately satisfy the illustrated
values.
NOTE: The temperature conditions when checking should
not exceed the range shown in the diagram.
Q: Is the interior temperature sensor in good condition?
YES : Replace the A/C-ECU. Then go to Step 7.
NO : Replace the interior temperature sensor. Then go to
St e p 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 VENTILATION55-16
DTC B1011, B1012: Ambient Air Temperature Sensor System
If DTC B1011 or B1012 has been set, multi-dis-
play related DTC U1130 is also set. After B1011 or
B1012 has been diagnosed, don't forget to erase
DTC U1130.
.
DTC SET CONDITION
DTC B1011 is set if there is a short circuit in the
ambient air temperature sensor input circuit.
DTC B1012 is set if there is a defective connector
connection, or if there is an open circuit in the
harness.
.
TECHNICAL DESCRIPTION (COMMENT)
Current trouble
The A/C-ECU, the ambient air temperature sen-
sor, or connector(s) or wiring between the two
may be defective.Past trouble
If DTC B1011 or B1012 is stored as a past trou-
ble, carry out diagnosis with particular emphasis
on wiring and connector(s) between the A/C-ECU
and the ambient air temperature sensor. If the
connectors and wiring are normal, and obviously
the ECU is the cause of the trouble, replace the
ECU. If in doubt, do not replace the ECU.
TROUBLESHOOTING HINT
Malfunction of connector.
Malfunction of the harness.
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

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-17
DIAGNOSIS
Required Special Tool:
: Diagnostic 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 diagnostic tool , diagnose the CAN bus line.
Use diagnostic tool to diagnose the CAN bus lines.
(1) Connect diagnostic tool to the data link connector.
(2) Turn the ignition switch to "ON" position.
(3) Diagnose the CAN bus line.
Q: Is the check result satisfactory?
YES : Go to Step 2.
NO : Repair the CAN bus lines. Repair the CAN bus lines
(Refer to GROUP 54C, Diagnosis-Can Bus
Diagnostic Chart P.54C-405). Then go to Step 8.
STEP 2. Recheck for diagnostic trouble code.
Recheck if the DTC is set.
(1) Erase the DTC.
(2) Turn the ignition switch to "ON" position.
(3) Check if the DTC is set.
Q: Is the check result satisfactory?
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.
NO : Go to Step 3.

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-18
STEP 3. Using diagnostic tool , check data list item 58:
Outside air temperature 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) Start the engine.
(3) Set diagnostic tool to the data reading mode for item 58:
Outside air temperature sensor.
Check that the ambient temperature matches the dis-
played value on the diagnostic tool.
NOTE: When this DTC is set and the system is fail-safe sta-
tus, the value of service data displays 20
C.
(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 8.
NO : Go to Step 4.
STEP 4. Check ambient air temperature sensor connector
A-25 for loose, corroded or damaged terminals, or
terminals pushed back in the connector.
Q: Is ambient air temperature sensor connector A-25 in
good condition?
YES : Go to Step 5.
NO : Repair or replace the connector. Refer to GROUP
00E, Harness Connector Inspection P.00E-2. Then go
to Step 8.

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-19
STEP 5. Check the ambient air temperature sensor.
(1) Disconnect ambient air temperature sensor connector A-25.
(2) 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 6.
NO : Replace the ambient air temperature sensor. Then go
to Step 8.
STEP 6. Check A/C-ECU connector C-15 and C-16 for
loose, corroded or damaged terminals, or terminals
pushed back in the connector.
Q: Are A/C-ECU connectors C-15 and C-16 in good
condition?
YES : Go to Step 7.
NO : Repair or replace the connector. Refer to GROUP
00E, Harness Connector Inspection P.00E-2. Then go
to Step 8.