Mitsubishi Galant (2004+). Manual - part 722

MANUAL A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-27

STEP 6. Check the air mixing damper control motor and
potentiometer.

CAUTION

Do not apply battery voltage when the damper is in the
MAX COOL or MAX HOT position.
(1) Operate the air mixing damper control motor as described

in the table below.

(2) Measure the resistances between connector terminals 3

and 5, and between 3 and 7, while the air mixing damper
control motor is running. The resistances should change
gradually within the standard value.

Standard value: 1.7 (MAX HOT)

− 5.0 (MAX COOL)

Ω

Q: Are the air mixing damper control motor and

potentiometer in good condition?
YES : Replace the A/C-ECU. Then go to Step 7.
NO : Replace the air mixing damper control motor and

potentiometer. Then go to Step 7 .

LEVER POSITION BATTERY

CONNECTION

LEVER
OPERATION

At the MAX COOL
position

• Connect

terminal 2 to the
positive battery
terminal

• Connect

terminal 1 to the
negative battery
terminal

The lever moves
from the MAX
COOL position to
the MAX HOT
position

At the MAX HOT
position

• Connect

terminal 1 to the
positive battery
terminal

• Connect

terminal 2 to the
negative battery
terminal

The lever moves
from the MAX HOT
position to the MAX
COOL position

AC206296

MAX HOT POSITION

MAX COOL POSITION

1 2

MANUAL A/C DIAGNOSIS

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HEATER, AIR CONDITIONING AND VENTILATION

55A-28

STEP 7. Recheck for diagnostic trouble code.

Check again if the DTC is set.

1. Connect scan tool MB991958 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 : The procedure is complete.
NO : Return to Step 1.

AC305412

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

MANUAL A/C DIAGNOSIS

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HEATER, AIR CONDITIONING AND VENTILATION

55A-29

DTC B1045: Air mixing damper control motor and potentiometer (activating system failure)

DTC SET CONDITION

• If the air mixing damper control motor does not

work normally, DTC No.B1045 will be set.

TECHNICAL DESCRIPTION (COMMENT)

Current trouble

• The A/C-ECU, the air mixing damper control

motor and potentiometer, or connector(s) or wir-
ing between the two may be defective.

Past trouble

• If DTC B1045 is stored as a past trouble, carry

out diagnosis with particular emphasis on wiring
and connector(s) between the A/C-ECU and the
air mixing damper control motor and potentiome-
ter. If the connectors and wiring are normal, and
obviously the ECU is the cause of the trouble,
replace the ECU. If in doubt, do not replace the
ECU.

TROUBLESHOOTING HINT

• Malfunction of connector.

• Malfunction of the harness.

• Malfunction of the air mixing damper control

motor and potentiometer.

• Malfunction of the A/C-ECU.

AIR MIXING
DAMPER CONTROL
MOTOR AND
POTENTIOMETER

A/C-ECU

MOTOR
DRIVE
CIRCUIT

Air Mixing Damper Control Motor Circuit

AC305233

CONNECTORS: C-09, C-10, C-105

C-09 (B)

C-10 (B)

C-105

MANUAL A/C DIAGNOSIS

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HEATER, AIR CONDITIONING AND VENTILATION

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DIAGNOSIS

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)

STEP 1. Using scan tool MB991958, diagnose the CAN bus
line.

Use scan tool MB991958 to diagnose the CAN bus lines.
(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to "ON" position.

(3) Diagnose the CAN bus line.
Q: Is the check result satisfactory?

YES : Go to Step 2.
NO : Repair the CAN bus lines. (Refer to GROUP 54C,

Diagnosis-Can Bus Diagnostic Chart

P.54C-621

Then go to Step 7.

STEP 2. Recheck for diagnostic trouble code.

Recheck if the DTC is set.

1. Erase the DTC.
2. Turn the ignition switch to "ON" position.
3. Check if the DTC is set.

Q: Is the check result satisfactory?

YES : It can be assumed that this malfunction is intermittent.

Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points

− How to