Mitsubishi Montero (2004+). Manual - part 630

AUTO A/C DIAGNOSIS

TSB Revision

AUTOMATIC AIR CONDITIONING

55B-9

STEP 2. Check the flexible flat cable (FFC) connection.

(1) The FFC is connected to the A/C control panel assembly. 

Check that the FFC connection is not contaminated with 
foreign material or loose (Refer to 

P.55B-142

).

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

YES : Replace the automatic air conditioning control panel. 

Then go to Step 3.

NO :  Replace the FFC. Then go to Step 3.

STEP 3. Recheck for diagnostic trouble code.
Q: Is DTC 11 or 12 set?

YES : Replace the A/C-ECU.
NO :  The procedure is complete.

DTC 13, 14: Ambient Air Temperature Sensor System

AC205264AB

AHBIENT AIR
TEMPERATURE
SENSOR

A/C-ECU

SIGNAL INPUT
CIRCUIT

Outside Air Temperature Sensor Circuit

AUTO A/C DIAGNOSIS

TSB Revision

AUTOMATIC AIR CONDITIONING

55B-10

.

DTC SET CONDITION

• DTC 13 is set if there is a defective connector 

connection, or if there is an open circuit in the 
harness.

• DTC 14 is set if there is a short circuit in the ambi-

ent air temperature sensor input circuit.

.

TROUBLESHOOTING HINT

• Malfunction of connector.

• Malfunction of the harness.

• Malfunction of the ambient air temperature sen-

sor.

• Malfunction of the A/C-ECU.

DIAGNOSIS

Required Special Tools:

• MB991223: Harness Set

• MB991958: Scan Tool (MUT-III Sub Assembly)

• MB991824: Vehicle Communication Interface (V.C.I.)

• MB991827: MUT-III USB Cable

• MB991911: MUT-III Main Harness B (Vehicles without 

CAN communication system)

STEP 1. Using scan tool MB991958, check data list item 13: 
Ambient air temperature sensor.

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.
Item 13: Ambient air temperature sensor
OK: The outside air temperature and indicated temperature on 
scan tool MB991958 are almost equal. 
Q: Are the outside air temperature and temperature 

displayed on scan tool MB991958 almost equal?
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 2.

AC001534 AB

CONNECTOR: A-29

AC001536 AB

CONNECTORS: D-24, D-28

D-24

D-28

AC307591 AB

MB991911

DATA LINK

CONNECTOR

MB991824

MB991827

AUTO A/C DIAGNOSIS

TSB Revision

AUTOMATIC AIR CONDITIONING

55B-11

STEP 2. Check the ambient air temperature sensor.

Disconnect ambient air temperature sensor connector A-29, 
and measure the resistance between terminal numbers 1 and 
2.
Measure the resistance between the sensor terminals under at 
least two temperatures. 
NOTE: The temperature conditions at the check should be 
within the range shown in the characteristic diagram.
Q: Is the check result normal?

YES : Go to Step 3.
NO :  Replace the ambient air temperature sensor. Then go 

to Step 5.

AC204166

CONNECTOR : A-29

AP

A-29(B)

A-29(B)

1

2

HARNESS 
SIDE

AC001680AB

OUTSIDE AIR 
TENPERATURE SENSOR

REGISTANCE k

Ω

10

8

6

4

2

0

-10

0

10

20

30

40

(14) (32)

(50)

(68)

(86) (104)

TEMPERATURE ˚C (˚F)

AUTO A/C DIAGNOSIS

TSB Revision

AUTOMATIC AIR CONDITIONING

55B-12

STEP 3. Check ambient air temperature sensor connector 
A-29 and A/C-ECU connector D-24 for damage.

Q: Is ambient air temperature sensor connector A-29 and 

A/C-ECU connector D-24 in good condition?
YES : Go to Step 4.
NO :  Repair or replace the connector. Refer to GROUP 

00E, Harness Connector Inspection 

P.00E-2

. Then go 

to Step 5.

STEP 4. Check the wiring harness between ambient air 
temperature sensor connector A-29 (terminals 1 and 2) and 
A/C-ECU D-24 (terminals 22 and 29).

AC204166

CONNECTOR : A-29

AP

A-29(B)

A-29(B)

1

2

HARNESS 
SIDE

AC204170

CONNECTOR : D-24

D-24(B)

D-24(B)

CQ

22

23

30

31

25

26

33

34

32

24

28

3635

27

29

21

HARNESS 
SIDE

AC204166

CONNECTOR : A-29

AP

A-29(B)

A-29(B)

1

2

HARNESS 
SIDE

AC204170

CONNECTOR : D-24

D-24(B)

D-24(B)

CQ

22

23

30

31

25

26

33

34

32

24

28

3635

27

29

21

HARNESS 
SIDE