Mitsubishi Montero (2004+). Manual — part 649

AUTO A/C DIAGNOSIS

TSB Revision

AUTOMATIC AIR CONDITIONING

55B-85

STEP 1. Using scan tool MB991958, read the diagnostic
trouble code.

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) Turn the ignition switch to the "ON" position.
(2) Check if the DTC is set.
(3) Turn the ignition switch to the "LOOK (OFF)" position.
Q: Is diagnostic trouble code No.32 set?

YES : Check the air outlet changeover damper

potentiometer system. Refer to

P.55B-24

.

NO : Go to Step 2.

STEP 2. Using scan tool MB991958, check data list item 32:
Mode selection damper control motor and potentiometer.

Check the data list.
Item 32: mode selection damper control motor and potentiome-
ter
Q: Does the data list show approximately 0% (at FACE

position), approximately 60% (at FOOT position),
approximately 80% (at FOOT/DEF position), and
approximately 100% (at DEF position)?
YES : It can be assumed that this malfunction is intermittent

(Refer to GROUP 00 - How to Cope with Intermittent
Malfunction

P.00-6

).

NO : Go to Step 3.

STEP 3. Using scan tool MB991958, check actuator test
item 08, item 09 and item 10: Blower motor

Item 08 (FACE), 09 (FOOT) and 10 (DEF): Blower motor
Q: Is the check result normal?

YES : Go to Step 7.
NO : Go to Step 4.

AC307591 AB

MB991911

DATA LINK

CONNECTOR

MB991824

MB991827

AUTO A/C DIAGNOSIS

TSB Revision

AUTOMATIC AIR CONDITIONING

55B-86

STEP 4. Check the mode selection damper control motor
and potentiometer

CAUTION

Do not apply battery voltage when the damper is in the
FACE or DEF position.
Check the mode selection damper control motor by the follow-
ing procedures.

While checking the mode selection damper control motor, mea-
sure the resistances between terminal Nos. 3 and 5 as well as
terminal Nos. 3 and 7. At this time, the resistances should
change gradually within the standard value.

Standard value: 0.96

− 5.76 kΩ

Q: Does mode selection damper control motor and

potentiometer work normally?
YES : Go to Step 5.
NO : Replace the mode selection damper control motor

and potentiometer. Check the mode selection damper
control motor and potentiometer works normally.

LEVER POSITION BATTERY

CONNECTION

LEVER
OPERATION

At the DEF position

• Connect

terminal 1 to the
positive battery
terminal

• Connect

terminal 2 to the
negative battery
terminal

The lever moves
from the DEF
position to the
outside position

At the FACE
position

• Connect

terminal 2 to the
positive battery
terminal

• Connect

terminal 1 to the
negative battery
terminal

The lever moves
from the FACE
position to the
inside position

ACX01457

FACE POSITION

DEF POSITION

AB

AUTO A/C DIAGNOSIS

TSB Revision

AUTOMATIC AIR CONDITIONING

55B-87

STEP 5. Check mode selection damper control motor and
potentiometer connector D-22 and A/C-ECU connector
D-23 for damage.

Q: Is mode selection damper control motor and

potentiometer connector D-22 and A/C-ECU connector
D-23 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

the mode selection damper control motor and
potentiometer works normally.

STEP 6. Check the wiring harness between mode selection
damper control motor and potentiometer connector D-22
(terminals 1 and 2) and A/C-ECU D-23 (terminals 2 and 12).

Q: Is the wiring harness between mode selection damper

control motor and potentiometer connector D-22
(terminals 1 and 2) and A/C-ECU D-23 (terminals 2 and
12) in good condition?
YES : Go to Step 7.
NO : Repair the wiring harness. Check the mode selection

damper control motor and potentiometer works
normally.

AC204188

CONNECTOR : D-22, D-23

D-22(B)

D-22(B)

CL

7 6 5 4 3 2 1

HARNESS SIDE

D-23(B)

HARNESS SIDE

1

3

4

2

12

1413

11

6

7

8

10 9

18

19

20

16

17

5

15

D-23(B)

AC204188

CONNECTOR : D-22, D-23

D-22(B)

D-22(B)

CL

7 6 5 4 3 2 1

HARNESS SIDE

D-23(B)

HARNESS SIDE

1

3

4

2

12

1413

11

6

7

8

10 9

18

19

20

16

17

5

15

D-23(B)

AUTO A/C DIAGNOSIS

TSB Revision

AUTOMATIC AIR CONDITIONING

55B-88

STEP 7. Check the flexible flat cable (FFC).

(1) The FCC is connected to the automatic air conditioning

control panel assembly. Check that the FCC connection is
contaminated with foreign material or loose (Refer to

P.55B-142

).

(2) There should be continuity across the FFC terminals.
Q: Is the FFC normal?

YES : Go to Step 8.
NO : Repair the FFC (Refer to

P.55B-142

). Check the

mode selection damper control motor and
potentiometer works normally.

STEP 8. Check the air outlet changeover switch.

Follow the table below to check the air outlet changeover
switch for continuity.

Q: Is the check result normal?

YES : Replace the A/C-ECU. Check the mode selection

damper control motor and potentiometer works
normally.

NO : Replace the automatic air-conditioning control panel.

Check the mode selection damper control motor and
potentiometer works normally.

AC205264AB

SWITCH
POSITION

TESTER
CONNECTION

SPECIFIED
CONDITION

AUTO

10

− 11

Less than 2 ohms

1

8

− 11, 10 − 11

Less than 2 ohms

2

8

− 11

Less than 2 ohms

3

6

− 11, 8 − 11

Less than 2 ohms

4

6

− 11, 8 − 11, 10 − 11 Less than 2 ohms

5

6

− 11, 10 − 11

Open circuit

6

6

− 11

Less than 2 ohms

7

4

− 11, 6 − 11

Less than 2 ohms

8

4

− 11, 6 − 11, 10 − 11 Less than 2 ohms

9

4

− 11, 6 − 11, 8 − 11,

10

− 11

Less than 2 ohms

10

4

− 11, 6 − 11, 8 − 11 Less than 2 ohms

11

4

− 11, 8 − 11

Less than 2 ohms

12

4

− 11, 8 − 11, 10 − 11 Less than 2 ohms

13

4

− 11, 10 − 11

Less than 2 ohms

AC205403

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

AD

AC205261AB

AUTO

8

7

6

5

4

3

2

1

12

11

10

9

13