2005 MITSUBISHI 380 Workshop Manual

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-36
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. (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 VENTILATION55-37
STEP 3. Using diagnostic tool , check actuator test item 42,
43: air mix damper motor.
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) Use diagnostic tool to run the actuator test.
Item 42: air mix damper motor (0% MAX COOL position)
Item 43: air mix damper motor (100% MAX HOT position)
Check that the air mixing damper control motor oper-
ates.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Does the motor operate normally?
YES : Replace the A/C-ECU. Then go to Step 7.
NO : Go to Step 4.
STEP 4. Check A/C-ECU connectors C-15 and air mixing
damper control motor and potentiometer connector C-105
for loose, corroded or damaged terminals, or terminals
pushed back in the connector.
Q: Are A/C-ECU connectors C-15 and air mixing damper
control motor and potentiometer connector C-105 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 VENTILATION55-38
STEP 5. Check the wiring harness between A/C-ECU
connectors C-15 (terminal 1 and 2) and air mixing damper
control motor and potentiometer connector C-105
(terminals 1 and 2).
Q: Are the wiring harness between A/C-ECU connectors
C-15 (terminals 1 and 2) and air mixing damper control
motor and potentiometer connector C-105 (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 VENTILATION55-39
STEP 6. Check the air mixing damper control motor and
potentiometer.
Do not apply battery voltage when the damper is in the
MAX COOL or MAX HOT position.
Check the air mix damper control motor by the following proce-
dures.
Q: Are the air mixing damper control motor and
potentiometer in good condition?
YES : Replace the A/C-ECU. Then go to Step 7.
NO : Replace the air mixing damper control motor and
potentiometer. Then go to Step 7. LEVER POSITION BATTERY
CONNECTIONLEVER
OPERATION
At the MAX COOL
position
Connect
terminal 2 to the
positive battery
terminal
Connect
terminal 1 to the
negative battery
terminalThe lever moves
from the MAX
COOL position to
the MAX HOT
position
At the MAX HOT
position
Connect
terminal 1 to the
positive battery
terminal
Connect
terminal 2 to the
negative battery
terminalThe lever moves
from the MAX HOT
position to the MAX
COOL position

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-40
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 VENTILATION55-41
DTC B1061, B1062: Mode Selection Damper Control Motor and Potentiometer
.
DTC SET CONDITION
DTC B1061 or B1062 is set if there is an open or
short circuit in the potentiometer input circuit, or if
there is an open in the power circuit or ground cir-
cuit.
.
TECHNICAL DESCRIPTION (COMMENT)
Current trouble
The A/C-ECU, the mode selection damper con-
trol motor and potentiometer, or connector(s) or
wiring between the two may be defective.Past trouble
If DTC B1061 or B1062 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 mode selection damper control motor
and potentiometer. 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 mode selection damper control
motor and potentiometer.
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 VENTILATION55-42
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. (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 VENTILATION55-43
STEP 3. Using diagnostic tool , check data list item 55: Air
outlet c/o potentiometer.
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 55: Air
outlet c/o potentiometer.
Check that the set position of the heater control matches
the displayed position on the diagnostic tool.
(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.