air conditioning MITSUBISHI 380 2005 Manual Online

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-72
NOTE: Also check junction block connectors C-211(terminal
16) and C-215 (terminal 2) for loose, corroded, or damaged ter-
minals, or terminals pushed back in the connector. If junction
block connector C-211 or C-215 is damaged, repair or replace
the connector as described in GROUP 00E, Harness Connec-
tor Inspection P.00E-2.
Q: Is the wiring harness between outside/inside air
selection damper control motor connector C-106
(terminal 1) and the ignition switch (IG2) 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. Check that the
outside/inside air selection damper control motor
works normally.

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-73
STEP 5. Check the outside/inside air selection damper
control motor.
Cut off the battery voltage when the damper is in the
inside/outside air position.
Check the outside/inside air selection damper control motor by
the following procedures.
Q: Does outside/inside air selection damper control motor
work normally?
YES : Go to Step 6.
NO : Replace the outside/inside air selection damper
control motor. Check that the outside/inside air
selection damper control motor works 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. Check
that the outside/inside air selection damper control
motor works normally. LEVER POSITION BATTERY
CONNECTIONLEVER
OPERATION
At the outside
position
Connect
terminal 1 to the
positive battery
terminal
Connect
terminal 5 to the
negative battery
terminalThe lever moves
from the outside
position to the
inside position
At the inside
position
Connect
terminal 1 to the
positive battery
terminal
Connect
terminal 4 to the
negative battery
terminalThe lever moves
from the inside
position to the
outside position

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-74
STEP 7. Check the wiring harness between outside/inside
air selection damper control motor connector C-106
(terminals 5 and 7) and A/C-ECU C-15 (terminals 5 and 6).
Q: Are the wiring harness between outside/inside air
selection damper control motor connector C-106
(terminals 4 and 5) and A/C-ECU C-16 (terminals 5 and
6) in good condition?
YES : Go to Step 8.
NO : Repair the wiring harness. Check that the
outside/inside air selection damper control motor
works normally.
STEP 8. Retest the system.
Q: Does a malfunction take place again?
YES : Replace the A/C-ECU, and check that the
outside/inside air selection damper control motor
works normally.
NO : 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.

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 VENTILATION55-76
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. Check the defogger and outside/inside air
selection damper control motor operation.
Q: Do the defogger 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 system P.55-122."
STEP 2. Check the blower motor operation.
Q: Does the blower motor work normally?
YES : Go to Step 3.
NO : Refer to Inspection procedure 5, "Front blower fan
and motor do not turn P.55-89."
STEP 3. Check the A/C compressor.
Check the A/C compressor for compressor oil leaks.
Q: Is the check result satisfactory?
YES : Go to Step 4.
NO : Replace the A/C compressor or the expansion valve.
STEP 4. Using scan tool , read the A/C 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 5.
NO : Refer to DIAGNOSTIC TROUBLE CODE CHART
P.55-9.

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-77
STEP 5. Check A/C compressor clutch relay connector
B-18X for loose, corroded or damaged terminals, or
terminals pushed back in the connector.
Q: Is A/C compressor clutch relay connector B-18X 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.
STEP 6. Check the A/C compressor clutch relay continuity.
Follow the table below to check the A/C compressor clutch
relay for continuity.
Q: Is the A/C compressor clutch relay in good condition?
YES : Go to Step 7.
NO : Replace the A/C compressor clutch relay. Check that
the air conditioning works normally.
BATTERY
VOLTAGETESTER
CONNECTIONSPECIFIED
CONDITION
Not applied 1
4 Open circuit
Connect
terminal 2 to the
positive battery
terminal
Connect
terminal 3 to the
negative battery
terminal1
4 Less than 2 ohms

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-78
STEP 7. Check Engine ECU connector B-20 and A/C
compressor assembly B-28 for loose, corroded or
damaged terminals, or terminals pushed back in the
connector.
Q: Are Engine ECU connector B-20 and A/C compressor
assembly B-28 in good condition?
YES : Go to Step 8.
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 VENTILATION55-79
STEP 8. Measure the voltage at A/C compressor assembly
connector B-28.
(1) Disconnect A/C compressor assembly connector B-28 and
measure the voltage at the relay box side.
(2) Disconnect powertrain control module connector B-20 and
ground harness side terminal No.6.
(3) Turn the ignition switch to the "ON" position.
(4) A/C compressor assembly connector B-28 terminal 1 and
ground.
The measured value should be approximately 12 volts
(battery positive voltage).
Q: Is the measured voltage approx. 12 volts?
YES : Go to Step 15.
NO : Go to Step 9.

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-80
STEP 9. Measure the voltage at A/C compressor clutch
relay connector B-18X.
The top and bottom of the A/C compressor connector are
difficult to identify. Prior to inspection, confirm the triangle
mark on the relay box.
(1) Disconnect A/C compressor connector B-18X and measure
the voltage at the relay box side.
(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal 2 and ground.
The measured value should be approximately 12 volts
(battery positive voltage).
Q: Is the measured voltage approx. 12 volts?
YES : Go to Step 11.
NO : Go to Step 10.
STEP 10. Check the wiring harness between A/C
compressor clutch relay connector B-18X (terminal 2) and
the ignition switch (IG2).

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-81
NOTE: Also check intermediate connector A-13, junction block
connectors C-214 and C-215 for loose, corroded, or damaged
terminals, or terminals pushed back in the connector. If inter-
mediate connector A-13, junction block connector C-214 or
C-215 is damaged, repair or replace the connector as
described in GROUP 00E, Harness Connector Inspection
P.00E-2.
Q: Is the wiring harness between A/C compressor clutch
relay connector B-18X (terminal 2) and the ignition
switch (IG2) 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. Check that the air
conditioning works normally.