Mitsubishi 380. Manual — part 177

GENERAL DESCRIPTION

HEATER, AIR CONDITIONING AND VENTILATION

55-4

OPERATION

.

CONDENSER FAN AND RADIATOR FAN
CONTROL

The ECU judges the required revolution speed of
radiator fan motor and condenser fan motor using
the input signals transmitted from A/C switch, output
shaft speed sensor and engine coolant temperature
sensor. The ECU activates the fan control relays to
drive the radiator fan motor and condenser fan
motor.

.

COMPRESSOR CONTROL

When operating the air conditioning switch

• The air thermo sensor, which senses the temper-

ature of the air flowing out of the evaporator,
deactivates the compressor at 3

°C (37.4°F) or

below.

• The dual pressure switch turns OFF when the

refrigerant pressure becomes excessively high or
low, thus protecting the compressor circuit (See
Table below).

• When the air thermo sensor is activated, and the

ignition switch, blower switch, and air condition-
ing switch are ON, the A/C compressor clutch
relay is energized.

When operating the mode selection dial

• The air conditioning will work when the mode

selection dial is set to the "Defroster" or
"Defroster/foot" position, or the temperature con-
trol dial is set to the "MAX A/C" position. In other
dial positions, when the air conditioning switch is
turned on, the air conditioning will work.

A/C Compressor Clutch Relay ON Conditions

Ignition switch (IG2)

ON

NOTE: A/C compressor clutch relay is
de-energized when any one switch, sensor
or control unit shown on the left turns off.

NOTE: The components marked by

*

communicate with the ECU. If the air thermo
sensor detects a temperature of 3

°C

(37.4

°F), the A/C-ECU will turn off the A/C

compressor clutch relay.

Blower switch

ON

Air conditioning switch, mode selection dial
defroster, defroster/foot position or temperature
control MAX A/C

ON

Air thermo sensor

*

Pressure detected
by A/C pressure
sensor

2940 kPa or less (If the
refrigerant pressure exceeds
2940 kPa, A/C compressor
clutch relay is not ON
condition until the refrigerant
pressure has been measured
up to 2350 kPa or less.)

ON

190 kPa or more (If the
refrigerant pressure falls short
of 190 kPa, A/C compressor
clutch relay is not ON
condition until the refrigerant
pressure has been measured
up to 220 kPa or more.)

A/C compressor clutch relay driving transistor (within
ecu)

ON

AUTO A/C DIAGNOSIS

HEATER, AIR CONDITIONING AND VENTILATION

55-5

AUTO A/C DIAGNOSIS

INTRODUCTION

M1554006200062

After air is taken in through the damper, it is fed to
the evaporator by the blower fan and motor and
cooled. The air cooled by the air mix damper is
mixed appropriately with the warmed air to achieve a
comfortable temperature. If the A/C does not operate
or the cooled air is not discharged, the system com-
ponents or relay may be faulty.

AUTOMATIC AIR CONDITIONING TROUBLESHOOTING STRATEGY

M1554004700157

Use these steps to plan your diagnostic strategy. If
you follow them carefully, you will be sure that you
have exhausted most of the possible ways to find a
heater, air conditioning and ventilation fault.
1. Gather information from the customer.

2. Verify that the condition described by the

customer exists.

3. Find the malfunction by following the Symptom

Chart.

4. Verify malfunction is eliminated.

DIAGNOSTIC FUNCTION

M1552019800046

HOW TO CONNECT THE DIAGNOSTIC TOOL
(MUT-III)

Required Special Tools:

• : 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)

CAUTION

To prevent damage to diagnostic tool , always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting diagnostic tool .
1. Ensure that the ignition switch is at the "LOCK" (OFF)

position.

2. Start up the personal computer.

3. Connect special tool MB991827 to special tool MB991824

and the personal computer.

4. Connect special tool MB991910 to special tool MB991824

5. Connect special tool MB991910 to the data link connector.

6. Turn the power switch of special tool MB991824 to the "ON"

position.

NOTE: When the special tool MB991824 is energized, the
special tool MB991824 indicator light will be illuminated in a
green color.

7. Start the MUT-III system on the personal computer.

NOTE: Disconnecting the diagnostic tool special tool
MB991824 is the reverse of the connecting sequence, making
sure that the ignition switch is at the "LOCK" (OFF) position.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AUTO A/C DIAGNOSIS

HEATER, AIR CONDITIONING AND VENTILATION

55-6

HOW TO READ AND ERASE DIAGNOSTIC
TROUBLE CODES

Required Special Tools:

• : 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)

CAUTION

To prevent damage to diagnostic tool , always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting diagnostic tool .

NOTE: If the battery voltage is low, diagnostic trouble codes will
not be output. Check the battery if diagnostic tool does not dis-
play.
1. Connect the diagnostic tool to the data link connector.

2. Turn the ignition switch to the "ON" position.

3. Select "Interactive Diagnosis" from the start-up screen.

4. Select "System Select."

5. Choose "AUTO A/C" from the "BODY" tab.

6. Select "MITSUBISHI."

7. Select "Diagnostic Trouble Code."

8. If a DTC is set, it is shown.

9. Choose "Erase DTC" to erase the DTC.

HOW TO READ DATA LIST

Required Special Tools:

• : 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)

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AUTO A/C DIAGNOSIS

HEATER, AIR CONDITIONING AND VENTILATION

55-7

CAUTION

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 the diagnostic tool to the data link connector.

2. Turn the ignition switch to the "ON" position.

3. Select "Interactive Diagnosis" from the start-up screen.

4. Select "System Select."

5. Choose "AUTO A/C" from the "BODY" tab.

6. Select "MITSUBISHI."

7. Select "Data List."

8. Choose an appropriate item and select the "OK" button.

HOW TO PERFORM ACTUATOR TEST

Required Special Tools:

• : 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)

CAUTION

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 the diagnostic tool to the data link connector.

2. Turn the ignition switch to the "ON" position.

3. Select "Interactive Diagnosis" from the start-up screen.

4. Select "System Select."

5. Choose "AUTO A/C" from the "BODY" tab.

6. Select "MITSUBISHI."

7. Choose "Actuator Test" from "AUTO A/C" screen.

8. Choose an appropriate item and select the "OK" button.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827