Mitsubishi Galant 9G. Manual - part 238

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.

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

AC305412

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AIR MIXING
DAMPER CONTROL
MOTOR AND
POTENTIOMETER

A/C-ECU

MOTOR
DRIVE
CIRCUIT

Air Mixing Damper Control Motor Circuit

MANUAL A/C DIAGNOSIS

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HEATER, AIR CONDITIONING AND VENTILATION

55A-29

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.

AC305233

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

C-09 (B)

C-10 (B)

C-105

MANUAL A/C DIAGNOSIS

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55A-30

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-607

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

Cope with Intermittent Malfunctions

P.00-14

NO : Go to Step 3.

AC305412

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

MANUAL A/C DIAGNOSIS

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55A-31

STEP 3. Using scan tool MB991958, check actuator test
item 10, 11, 12: air mix damper motor.

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 scan tool MB991958 to the data link connector.
(2) Start the engine.
(3) Use scan tool MB991958 to run the actuator test.

Item 10: air mix damper motor (MAX COOL position)
Item 11: air mix damper motor (middle position)
Item 12: air mix damper motor (MAX HOT position)

• Check that the air mixing damper control motor oper-

ates.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Does the motor operate normally?

YES : Replace the A/C-ECU. Then go to Step 7.
NO : Go to Step 4.

STEP 4. Check A/C-ECU connectors C-09, C-10 and air
mixing damper control motor and potentiometer connector
C-105 for loose, corroded or damaged terminals, or
terminals pushed back in the connector.
Q: Are A/C-ECU connectors C-09, C-10 and air mixing

damper control motor and potentiometer connector
C-105 in good condition?
YES : Go to Step 5.
NO : Repair or replace the connector. Refer to GROUP

00E, Harness Connector Inspection

P.00E-2

. Then go

to Step 7.

AC305412

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AC305234

C-09 (B)

C-10 (B)

HARNESS SIDE

C-09

HARNESS SIDE

C-105

C-10

HARNESS SIDE

C-105

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

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