Mitsubishi Galant 9G. Manual — part 232

GENERAL DESCRIPTION

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HEATER, AIR CONDITIONING AND VENTILATION

55A-4

OPERATION

.

CONDENSER FAN AND RADIATOR FAN
CONTROL

The PCM 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 PCM 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 PCM. 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

2.94 MPa or less (If the
refrigerant pressure exceeds
2.94 MPa, A/C compressor
clutch relay is not ON
condition until the refrigerant
pressure has been measured
up to 235 MPa or less.)

ON

0.19 MPa or more (If the
refrigerant pressure falls short
of 0.19 MPa, A/C compressor
clutch relay is not ON
condition until the refrigerant
pressure has been measured
up to 0.22 MPa or more.)

A/C compressor clutch relay driving transistor (within
powertrain control module)

ON

SERVICE PRECAUTIONS

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HEATER, AIR CONDITIONING AND VENTILATION

55A-5

SERVICE PRECAUTIONS

CAUTION LABELS

M1552017400097

The refrigerant gas warning label must be affixed in the location
shown in the figure on the left. Follow the instructions on the
label when servicing.

MANUAL A/C DIAGNOSIS

INTRODUCTION TO HEATER, AIR CONDITIONING AND VENTILATION DIAGNOSIS

M1552012200333

Air is drawn into the heater assembly from either the
outside, or from the inside of the passenger cabin if
DEFROST, maximum cooling or RECIRCULATION
are selected. The air is then forced through the evap-
orator where heat is removed, cooling and de-humid-
ifying the air. Depending on the temperature
selected, a portion of this air is then forced through
the heater core to achieve the selected discharge
temperature.

If the system does not cool properly, look for a prob-
lem with the refrigerant, blower or air distribution sys-
tems. If the system does not heat properly, look for a
problem with the coolant, blower or air distribution
systems. In either case all system fuses, circuit
breaker and relays should be checked.

HEATER, AIR CONDITIONING AND VENTILATION DIAGNOSTIC TROUBLESHOOTING
STRATEGY

M1552009600386

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 that the malfunction is eliminated.

No.

Contents

1

Name of air conditioner manufacturer

2

Amount of refrigerant

3

Name of compressor oil

4

Parts number

AC306336

AC306936

AB

AC200079

1

2

3

3

2

AB

4

MANUAL A/C DIAGNOSIS

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HEATER, AIR CONDITIONING AND VENTILATION

55A-6

DIAGNOSTIC FUNCTION

M1552019800035

HOW TO CONNECT THE SCAN TOOL (MUT-III)

Required Special Tool:

• MB991958: 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)

CAUTION

To prevent damage to scan tool MB991958, always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
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 scan tool special tool MB991824 is
the reverse of the connecting sequence, making sure that the
ignition switch is at the "LOCK" (OFF) position.

HOW TO READ AND ERASE DIAGNOSTIC
TROUBLE CODES

Required Special Tool:

• MB991958: 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)

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

MANUAL A/C DIAGNOSIS

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HEATER, AIR CONDITIONING AND VENTILATION

55A-7

CAUTION

To prevent damage to scan tool MB991958, always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
NOTE: If the battery voltage is low, diagnostic trouble codes will
not be output. Check the battery if scan tool MB991958 does
not display.
1. Connect the scan tool MB991958 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 "Air Conditioner" 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 Tool:

• MB991958: 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)

CAUTION

To prevent damage to scan tool MB991958, always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
1. Connect the scan tool MB991958 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 "Air Conditioner" from the "BODY" tab.
6. Select "MITSUBISHI."
7. Select "Data List."
8. Choose an appropriate item and select the "OK" button.

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827