Mitsubishi Outlander (2013+). Manual - part 742

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-24

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnostics
Use the M.U.T.-III to diagnose the CAN bus lines.

Q: Is the check result normal?

YES : 

Go to Step 2.

NO : 

Repair the CAN bus lines. (Refer to GROUP 
54C 

− Troubleshooting ).

STEP 2. M.U.T.-III diagnosis code
Check whether the A/C sets a diagnosis code or not.

Q: Is the check result normal?

YES : 

Go to Step 3.

NO : 

Refer to diagnosis code chart 

P.55-7

.

STEP 3. Voltage measurement at A/C compressor 
assembly connector.
(1) Disconnect the connector, and measure at the 

wiring harness side.

(2) Turn the ignition switch to the "ON" position.
(3) Disconnect engine-ECU connector and earth 

terminal 102.

(4) Voltage between terminal 1 and body earth.

OK: System voltage

Q: Is the check result normal?

YES : 

Go to Step 4.

NO : 

Go to Step 8.

STEP 4. Check the A/C compressor.
Refer to 

P.55-51

.

Q: Is the check result normal?

YES : 

Go to Step 5.

NO : 

Replace the A/C compressor.

STEP 5. Check the refrigerant temperature 
switch.
Refer to 

P.55-54

.

Q: Is the refrigerant temperature switch operating 

properly?
YES : 

Go to Step 6.

NO : 

Replace the refrigerant temperature switch.

STEP 6. Check the refrigerant level.
Refer to 

P.55-34

.

Q: Is the refrigerant level correct?

YES : 

Go to Step 7.

NO : 

Correct the refrigerant level (Refer to 
On-vehicle Service 

P.55-34

).

STEP 7. Replace the A/C-ECU, and then recheck 
the trouble symptom
Check that the compressor works normally.

Q: Is the check result normal?

YES : 

This diagnosis is complete.

NO : 

Replace the engine-ECU (Refer to GROUP 
13A 

− Engine-ECU ).

STEP 8. Check the A/C compressor relay
Refer to 

P.55-41

.

Q: Is the check result normal?

YES : 

Go to Step 9.

NO : 

Replace the A/C compressor relay.

STEP 9. Voltage measurement at A-14X A/C 
compressor relay connector.
(1) Remove the relay, and measure at the relay block 

side.

(2) Voltage between terminal 2, 4 and body earth.

OK: System voltage

Q: Is the check result normal?

YES : 

Go to Step 11.

NO : 

Go to Step 10.

STEP 10. Check of open circuit in A/C 
compressor relay power supply line between 
fusible link and A/C compressor relay connector.

Q: Is the check result normal?

YES : 

The trouble can be an intermittent 

malfunction (Refer to GROUP 00, How to 
Cope with Intermittent Malfunction ).

NO : 

Repair the wiring harness.

STEP 11.Check of open circuit in A/C 
compressor relay power supply line between A/C 
compressor relay connector and A/C 
compressor assembly connector.

NOTE: Prior to the wiring harness inspection, check 
intermediate connector and repair if necessary.

Q: Is the check result normal?

YES : 

Go to Step 12.

NO : 

Repair the connector(s) or wiring harness.

STEP 12. Check of open circuit in AC/R line 
(engine-ECU) between A/C compressor relay 
connector and engine-ECU connector.

Q: Is the check result normal?

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-25

YES : 

The trouble can be an intermittent 

malfunction (Refer to GROUP 00, How to 
Cope with Intermittent Malfunction ).

NO : 

Repair the connector(s) or wiring harness.

INSPECTION PROCEDURE 7: A/C outlet air temperature cannot be set

COMMENTS ON TROUBLE SYMPTOM

If the air conditioner outlet temperature cannot be 
adjusted, the air mixing damper control motor or the 
heater controller assembly (A/C-ECU) may be faulty.

NOTE: It cannot be adjusted while the engine cool-
ant temperature is low.

PROBABLE CAUSES

• Malfunction of the air mix damper control motor

• Malfunction of the heater controller assembly 

(A/C-ECU)

DIAGNOSTIC PROCEDURE

STEP 1. Check the compressor operation
Check that the compressor operates under the fol-
lowing conditions.

• Engine operation

• Air volume control dial: Maximum

• Air conditioner switch: ON

• Temperature control dial: MAX COOL

Q: Is the check result normal?

YES : 

Go to Step 2.

NO : 

Refer to INSPECTION PROCEDURE 6: 
"The A/C compressor does not work 

P.55-23

.

STEP 2. M.U.T.-III diagnosis code
Check that the diagnosis code related to the air con-
ditioner is not set.

Q: Is the diagnosis code set?

YES : 

Carry out the diagnosis code procedures. 

Refer to 

P.55-7

.

NO <Single-zone AUTO A/C> : 

Go to Step 3.

NO <Dual-zone AUTO A/C> : 

Go to Step 5.

STEP 3. M.U.T.-III actuator test
Carry out the actuator test. (Refer to 

P.55-31

).

Item No.17: As air mix damper motor (Select 
"Damper position setting".)

Q: Is the check result normal?

YES : 

This diagnosis is complete.

NO : 

Go to Step 4.

STEP 4. Check of open circuit in IG1, A/DA, 
A/DA’, A/DB, A/DB’ line between air mixing 
damper control motor connector and heater 
controller assembly (A/C-ECU) connector.

Q: Is the check result normal?

YES : 

Go to Step 9.

NO : 

Repair the connector(s) or wiring harness.

STEP 5. M.U.T.-III actuator test
Carry out the actuator test. (Refer to 

P.55-31

).

Item No.16: Dr air mix damper motor (Select 
"Damper position setting".)

Q: Is the check result normal?

YES : 

Go to Step 7.

NO : 

Go to Step 6.

STEP 6. Check of open circuit in IG1, A/DA, 
A/DA’, A/DB, A/DB’ line between air mixing 
damper control motor connector (LH) and heater 
controller assembly (A/C-ECU) connector.

Q: Is the check result normal?

YES : 

Go to Step 9.

NO : 

Repair the connector(s) or wiring harness.

STEP 7. M.U.T.-III actuator test
Carry out the actuator test. (Refer to 

P.55-31

).

Item No.17: As air mix damper motor (Select 
"Damper position setting".)

Q: Is the check result normal?

YES : 

This diagnosis is complete.

NO : 

Go to Step 8.

STEP 8. Check of open circuit in IG1, A/PA, A/PA’, 
A/PB, A/PB’ line between air mixing damper 
control motor connector (RH) and heater 
controller assembly (A/C-ECU) connector.

Q: Is the check result normal?

YES : 

Go to Step 9.

NO : 

Repair the wiring harness.

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-26

STEP 9. Replace the air mixing damper control 
motor, and recheck the trouble symptom.
Check that A/C outlet air temperature can be 
adjusted.

NOTE: Whenever the motor is replaced, initialise the 
motor position by using the Actuator Test.

Q: Is the check result normal?

YES : 

This diagnosis is complete.

NO : 

Replace the heater controller assembly 
(A/C-ECU).

INSPECTION PROCEDURE 8: Air outlets changeover is impossible.

COMMENTS ON TROUBLE SYMPTOM

If the air conditioner outlets changeover is impossi-
ble, the mode selection damper control motor or the 
heater controller assembly (A/C-ECU) may be faulty.

PROBABLE CAUSES

• Malfunction of the mode selection damper control 

motor

• Malfunction of the heater controller assembly 

(A/C-ECU)

DIAGNOSTIC PROCEDURE

STEP 1. M.U.T.-III diagnosis code
Check that the diagnosis code related to the air con-
ditioner is not set.

Q: Is the diagnosis code set?

YES : 

Carry out the diagnosis code procedures. 

Refer to 

P.55-7

.

NO : 

Go to Step 2.

STEP 2. M.U.T.-III actuator test
Carry out the actuator test. (Refer to 

P.55-31

).

Item 08: Air outlet c/o damper: (Select "posi-
tion reset".)

Q: Is the check result normal?

YES : 

This diagnosis is complete.

NO : 

Go to Step 3.

STEP 3. Check of open circuit in IG1, M/MA, 
M/MA’ M/MB and M/MB’ line between mode 
selection damper control motor and heater 
control panel assembly (A/C-ECU) connector.

Q: Is the check result normal?

YES : 

Go to Step 4.

NO : 

Repair the connector(s) or wiring harness.

STEP 4. Replace the mode selection damper 
control motor, and recheck the trouble symptom.
Check that the air outlets can be changed.

NOTE: Whenever the motor is replaced, initialise the 
motor position by using the Actuator Test.

Q: Is the check result normal?

YES : 

This diagnosis is complete.

NO : 

Replace the heater controller assembly 
(A/C-ECU).

INSPECTION PROCEDURE 9: Ambient temperature sensor system

CAUTION

• When the ETACS-ECU of vehicles without 

KOS is replaced, the encrypted code of the 
ignition key needs to be registered to the 
ETACS-ECU. (If the encrypted code is not reg-
istered, the engine cannot be started. Regis-
ter the encrypted code as described in 
Immobilizer System 

− How to Register Key ID 

.)

COMMENTS ON TROUBLE SYMPTOM

If the ambient temperature sensor system is defec-
tive, a malfunction may be present in the wiring har-
ness between the ambient temperature sensor and 
the ETACS-ECU.

PROBABLE CAUSES

• Malfunction of the ambient temperature sensor

• Malfunction of the ETACS-ECU

• Damaged wiring harness or connectors

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-27

DIAGNOSTIC PROCEDURE

STEP 1. Inspection of the ambient temperature 
sensor
Refer to 

P.55-49

.

Q: Is the A/C pressure sensor normal?

YES : 

Go to Step 2.

NO : 

Replace the ambient temperature sensor.

STEP 2. Check of open circuit in AMB+ and AMB- 
line (ETACS-ECU) between ambient temperature 
sensor connector and ETACS-ECU connector.

Q: Is the check result normal?

YES : 

Go to Step 3.

NO : 

Repair the connector(s) or wiring harness.

STEP 3. Check the data list below on the 
M.U.T.-III.
All the following items in the data list should be nor-
mal (Refer to 

P.55-29

).

Item No.19: Ambient temperature sensor

Q: Is the check result normal?

YES : 

Go to Step 4.

NO : 

Replace the ETACS-ECU.

STEP 4. Retest the system.

Q: Is the check result normal?

YES : 

Intermittent malfunction (Refer to GROUP 

00 

− How to Use 

Troubleshooting/Inspection Service Points - 
How to Cope with Intermittent Malfunction ).

NO : 

Replace the ETACS-ECU.

INSPECTION PROCEDURE 10: A/C pressure sensor system

COMMENTS ON TROUBLE SYMPTOM

If the A/C pressure sensor system is defective, the 
wiring harness between the A/C pressure sensor and 
the heater controller assembly (A/C-ECU) is sus-
pected.

PROBABLE CAUSES

• Malfunction of the A/C pressure sensor

• Malfunction of the heater controller assembly 

(A/C-ECU)

• Damaged wiring harness or connectors

INSPECTION PROCEDURE 11: Blower motor power supply system

CAUTION

• When the ETACS-ECU of vehicles without 

KOS is replaced, the encrypted code of the 
ignition key needs to be registered to the 
ETACS-ECU. (If the encrypted code is not reg-
istered, the engine cannot be started. Regis-
ter the encrypted code as described in 
Immobilizer System 

− How to Register Key ID 

.)

COMMENTS ON TROUBLE SYMPTOM

If the blower motor is not energised, the blower relay 
system is suspected.

PROBABLE CAUSES

• Malfunction of the blower relay

• Damaged wiring harness or connectors

• Malfunction of the ETACS-ECU

DIAGNOSTIC PROCEDURE

STEP 1. Measure the voltage at blower relay 
connector.
(1) Remove the relay, and measure at the junction 

block side.

(2) Voltage between terminals 2, 4 and body earth

OK: System voltage

Q: Is the check result normal?

YES : 

Go to Step 3.

NO : 

Go to Step 2.

STEP 2. Check of open circuit in blower relay 
power supply line between blower relay 
connector and fusible link (5).

NOTE: Prior to the wiring harness inspection, check 
ETACS-ECU connector and repair if necessary.

Q: Is the check result normal?