2005 MITSUBISHI 380 heater

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 VENTILATION55-105
STEP 2. Using scan tool , check data list item 61: A/C
pressure sensor.
To prevent damage to scan tool , always turn the ignition
switch to the "LOCK" (OFF) position before connecting or
disconnecting scan tool .
(1) Connect scan tool to the data link connector.
(2) Assemble a manifold gauge onto the high pressure service
valve.
(3) Turn ON the engine and then turn ON the air conditioner
switch.
(4) Set scan tool to the data reading mode for item 61: A/C
pressure sensor.
Check that the refrigerant pressure matches the dis-
played value on the scan tool.
(5) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor within the specified range?
YES : Go to Step 7.
NO : Go to Step 3.

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-106
STEP 3. Check A/C pressure sensor connector A-30 for
loose, corroded or damaged terminals, or terminals
pushed back in the connector.
Q: Is A/C pressure sensor connector A-30 in good
condition?
YES : Go to Step 4.
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 VENTILATION55-107
STEP 4. Check the A/C pressure sensor.
(1) Assemble a gauge manifold on the high pressure service
valve.
(2) Disconnect the A/C pressure sensor connector and connect
special tool test harness MB991658 as shown in the
illustration.
(3) Turn ON the engine and then turn ON the air conditioner
switch.
(4) At this time, check to see that the voltage of A/C pressure
sensor terminal No. 2 reflects the specifications of the
figure.
NOTE: The allowance shall be defined as
5%.
Q: Is the A/C pressure sensor in good condition?
YES : Go to Step 5.
NO : Replace the A/C pressure sensor. Check that the air
conditioning works normally.

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.

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-110
INSPECTION PROCEDURE 8: Defogger Function Does Not Operate.
.
TECHNICAL DESCRIPTION (COMMENT)
If the defogger does not operate when the defogger
switch is turned on, the defogger relay system may
be defective.
.
TROUBLESHOOTING HINTS
Malfunction of the A/C-ECU
Malfunction of the defogger relay
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 the A/C and outside/inside air selection
damper control motor operation.
Q: Do the A/C and outside/inside air selection damper
control motor work normally?
YES : Go to Step 2.
NO : Refer to Inspection procedure 10, "Malfunction of the
A/C-ECU power supply systemP.55-122."