2005 MITSUBISHI 380 ECU

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-97
NOTE: Also check junction block connector C-211 for loose,
corroded, or damaged terminals, or terminals pushed back in
the connector. If junction block connector C-211 is damaged,
repair or replace the connector as described in GROUP 00E,
Harness Connector Inspection P.00E-2.
Q: Is the wiring harness between blower relay connector
C-202 (terminal 3) and A/C-ECU connector C-15
(terminal 9) in good condition?
YES : Go to Step 10.
NO : Repair the wiring harness. The blower motor should
operate normally.
STEP 10. Check the wiring harness between blower motor
connector C-115 (terminal 1) and blower relay connector
C-202 (terminal 4).
Q: Is the wiring harness between blower motor connector
C-115 (terminal 1) and blower relay connector C-202
(terminal 4) 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.
NO : Repair the wiring harness. The blower motor should
operate normally.
NOTE: Also check junction block connector C-215 for loose,
corroded, or damaged terminals, or terminals pushed back in
the connector. If junction block connector C-215 is damaged,
repair or replace the connector as described in GROUP 00E,
Harness Connector Inspection P.00E-2.
STEP 11. Check the blower fan and motor operation.
When battery voltage is applied between the terminals, check
that the motor operates. Also, check that there is no abnormal
noise.
Q: Is there any abnormal noise?
YES : Go to Step 12.
NO : Replace the blower relay. The blower motor should
operate normally.

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-99
STEP 15. Check the wiring harness between power
transistor connector C-104 (terminal 4) and blower motor
connector C-115 (terminal 2).
Q: Is the wiring harness between power transistor
connector C-104 (terminal 4) and blower motor
connector C-115 (terminal 2) in good condition?
YES : Go to Step 16.
NO : Repair the wiring harness. The blower motor should
operate normally.
STEP 16. Check the wiring harness between power
transistor connector C-104 (terminals 1 and 3) and
A/C-ECU connector C-15 (terminals 17 and 18).
Q: Are the wiring harness between power transistor
connector C-104 (terminals 1 and 3) and A/C-ECU
connector C-15 (terminals 17 and 18) in good condition?
YES : Go to Step 17.
NO : Repair the wiring harness. The blower motor should
operate normally.

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-100
STEP 17. Replace the power transistor.
Q: Does the blower motor operate normally?
YES : No action is necessary and testing is complete.
NO : Replace the A/C-ECU. Check that the air conditioning
works normally.
INSPECTION PROCEDURE 6: Front Blower Air Amount cannot be Changed.
.
CIRCUIT OPERATION
If the blower motor speed cannot be changed, the
power transistor circuit is suspected.
.
TROUBLESHOOTING HINTS
Malfunction of the power transistor
Malfunction of the front A/C-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 Tool:
MB991223: Test Harness Set
STEP 1. Check blower power transistor connector C-104
for loose, corroded or damaged terminals, or terminals
pushed back in the connector.
Q: Is power transistor connector C-104 in good condition?
YES : Go to Step 2.
NO : Repair or replace the connector. Refer to GROUP
00E, Harness Connector Inspection P.00E-2.The
blower motor should operate normally.

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-102
STEP 5. Check the wiring harness between power
transistor connector C-104 (terminal 4) and blower motor
connector C-115 (terminal 2).
Q: Is the wiring harness between power transistor
connector C-104 (terminal 4) and blower motor
connector C-115 (terminal 2) in good condition?
YES : Go to Step 6.
NO : Repair the wiring harness. The blower motor should
operate normally.
STEP 6. Check A/C-ECU connector C-15 for loose,
corroded or damaged terminals, or terminals pushed back
in the connector.
Q: Is A/C-ECU connector C-15 in good condition?
YES : Go to Step 7.
NO : Repair or replace the connector. Refer to GROUP
00E, Harness Connector Inspection P.00E-2.The
blower motor should operate normally.

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-103
STEP 7. Check the wiring harness between power
transistor connector C-104 (terminals 1 and 3) and
A/C-ECU connector C-15 (terminals 17 and 18).
Q: Are the wiring harness between power transistor
connector C-104 (terminals 1 and 3) and A/C-ECU
connector C-15 (terminals 17 and 18) in good condition?
YES : Go to Step 8.
NO : Repair the wiring harness. The blower motor should
operate normally.
STEP 8. Replace the power transistor.
Q: Does the blower motor operate normally?
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 : Replace the A/C-ECU. 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 VENTILATION55-108
STEP 5. Check A/C-ECU C-15 and C-16 for loose, corroded
or damaged terminals, or terminals pushed back in the
connector.
Q: Are A/C-ECU C-15 and C-16 in good condition?
YES : Go to Step 6.
NO : Repair or replace the connector. Refer to GROUP
00E, Harness Connector Inspection P.00E-2. Check
that the air conditioning works normally.

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-109
STEP 6. Check the wiring harness between A/C-ECU
connector C-15 (terminal 12), C-16 (terminals 34 and 26)
and A/C pressure sensor connector A-30 (terminals 3, 1
and 2).
Q: Is the wiring harness between A/C-ECU connector C-15
(terminal 12), C-16 (terminals 34 and 26) and A/C
pressure sensor connector A-30 (terminals 3, 1 and 2) in
good condition?
YES : Repair the A/C-ECU. Check that the air conditioning
works normally.
NO : Repair the wiring harness. Check that the air
conditioning works normally.
STEP 7. Check the refrigerant level.
Use the refrigerant recovery station to remove all of the refrig-
erant, and then calculate the amount of the refrigerant and
charge it.
Q: Is the refrigerant level correct?
YES : Replace the A/C-ECU.Check that the air conditioning
works normally.
NO : Correct the refrigerant level (Refer to On-vehicle
ServiceP.55-144). Check that the air conditioning
works normally.