Mitsubishi Outlander GS45X. Manual - part 1000

MANUAL A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-27

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

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. Refer to "How to connect the 

Scan Tool (M.U.T.-III) 

P.55A-7

."

(2) Turn the ignition switch to the "ON" position.
(3) Diagnose the CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the CAN bus line found to be normal?

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

Diagnosis 

P.54C-17

).

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.00-15

.

NO :  Go to Step 3. 

STEP 3. Check air thermo sensor connector C-118 and 
A/C-ECU connector C-108 for loose, corroded or damaged 
terminals, or terminals pushed back in the connector.
Q: Are air thermo sensor connector C-118 and A/C-ECU 

connector C-108 in good condition?
YES : Go to Step 4.
NO :  Repair or replace the connector. Refer to GROUP 

00E, Harness Connector Inspection 

P.00E-2

.

ZC501967

AC404789

AC701411AB

MB991824

MB991827

MB991910

Data link 
connector

MANUAL A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-28

STEP 4. Check the wiring harness between A/C-ECU 
connector C-108 (terminals 22 and 21) and air thermo 
sensor connector C-118 (terminals 1 and 2).

• Check the sensor signal line and ground line for open and 

short circuit.

Q: Is the wiring harness between A/C-ECU connector 

C-108 (terminals 22 and 21) and air thermo sensor 
connector C-118 (terminals 1 and 2) in good condition?
YES : Go to Step 5.
NO :  Repair the wiring harness.

STEP 5. Check the air thermo sensor.
Measure the resistance between connector terminals 1 and 2 
under at least two different temperatures. The resistance val-
ues should generally match those in the graph. 
NOTE: The temperature at the check should not exceed the 
range in the graph. 
Q: Is the air thermo sensor in good condition?

YES : Replace the A/C-ECU. Then go to Step 6.
NO :  Replace the air thermo sensor. Then go to Step 6.

STEP 6. 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.

AC609399

25

20

15

10

5

0

AB

10
(50)

30
(86)

Resistance

(k

Ω)

Temperature ºC (ºF)

  0
(32)

  40
(104)

-10
(14)

 20
(68)

MANUAL A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-29

DTC B1034, B1035: Ambient air temperature Sensor System

.

DTC SET CONDITION

• DTC B1034 is set if there is a short circuit in the 

ambient air temperature sensor input circuit.

• DTC B1035 is set if there is a defective connector 

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

.

TECHNICAL DESCRIPTION (COMMENT)

Current trouble

• The A/C-ECU, the ambient air temperature sen-

sor, or connector(s) or wiring between the two 
may be defective.

Past trouble

• If DTC B1034 or B1035 is stored as a past trou-

ble, carry out diagnosis with particular emphasis 
on wiring and connector(s) between the A/C-ECU 
and the ambient air temperature sensor. 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 ambient air temperature sen-

sor.

• Malfunction of the A/C-ECU.

DIAGNOSIS

Required Special Tool:

•  MB991958: Scan Tool (M.U.T.-III Sub Assembly)

AC702369

Ambient Air Temperature Sensor Circuit 

ETACS-ECU

ANALOG 
INTERFACE 
CIRCUIT

AB

AMBIENT AIR 
TEMPERATURE 
SENSOR

AC702370

Connector: A-44

A-44 (B)

AB

AC702828AE

Connector: C-312

MANUAL A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-30

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

• MB991827: M.U.T.-III USB Cable

• MB991910: M.U.T.-III Main Harness A (Vehicles with 

CAN communication system)

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

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. Refer to "How to connect the 

Scan Tool (M.U.T.-III) 

P.55A-7

."

(2) Turn the ignition switch to the "ON" position.
(3) Diagnose the CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the CAN bus line found to be normal?

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

Diagnosis 

P.54C-17

).

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.00-15

.

NO :  Go to Step 3. 

STEP 3. Check ambient air temperature sensor connector 
A-44 and ETACS-ECU connector C-312 for loose, corroded 
or damaged terminals, or terminals pushed back in the 
connector.
Q: Are ambient air temperature sensor connector A-44 and 

ETACS-ECU connector C-312 in good condition?
YES : Go to Step 4.
NO :  Repair or replace the connector. Refer to GROUP 

00E, Harness Connector Inspection 

P.00E-2

.

ZC501967

AC404789

AC701411AB

MB991824

MB991827

MB991910

Data link 
connector