Mitsubishi Evolution X. Manual - part 1286

AUTO A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55-95

STEP 3. Check the wiring harness between A/C-ECU 
connector C-20 (terminal 26, 25, 27, 24 and 29) and 
outside/inside air selection damper control motor 
connector C-111 (terminals 2, 5, 4. 1 and 3).
Q: Are the wiring harness between A/C-ECU connector 

C-20 (terminal 26, 25, 27, 24 and 29) and outside/inside 
air selection damper control motor connector C-111 
(terminals 2, 5, 4. 1 and 3) in good condition?
YES : Go to Step 4.
NO :  Repair the wiring harness. Check that the A/C works 

normally. 

STEP 4. Replace the outside/inside air selection damper 
control motor and check the trouble symptom again
Check the trouble symptom again.
Q: Is the check result satisfactory?

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

INSPECTION PROCEDURE 7: A/C Outlet Air Temperature does not Increase

Air Mixing Damper Control Motor Circuit 

AIR MIXING
DAMPER CONTROL
MOTOR

A/C-ECU

AC708623

AUTO A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55-96

.

CIRCUIT OPERATION

If the air outlet temperature cannot be adjusted, the air mixing 
damper control motor circuit may be failed.

.

TROUBLESHOOTING HINTS

• Malfunction of the air mixing damper control motor

• Malfunction of the A/C-ECU

• Damaged harness wires or connectors

DIAGNOSIS

Required Special Tools:

• MB991223: Harness Set

• MB992006: Extra Fine Probe

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

• MB991824: V.C.I.

• MB991827: M.U.T.-III USB Cable

• MB991910: M.U.T.-III Main Harness A

STEP 1. Using scan tool MB991958, check for diagnostic 
trouble code.
Check if an A/C-ECU 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 DTC set?

YES : Refer to DIAGNOSTIC TROUBLE CODE CHART 

P.55-71

.

NO :  Go to Step 2.

AC708951AS

C-20 (B)

Connectors: C-20, C-114

C-114

AC608435

Data link connector

MB991827

MB991824

MB991910

AB

AUTO A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55-97

STEP 2. Check air mixing damper control motor connector 
C-114 and A/C-ECU connector C-20 for loose, corroded or 
damaged terminals, or terminals pushed back in the 
connector.
Q: Are air mixing damper control motor connector C-114 

and A/C-ECU connector C-20 in good condition?
YES : Go to Step 3.
NO :  Repair or replace the connector. Refer to GROUP 

00E, Harness Connector Inspection 

P.00E-2

. Check 

that the A/C works normally. 

STEP 3. Check the wiring harness between A/C-ECU 
connector C-20 (terminal 29, 35, 36, 34 and 28) and air 
mixing damper control motor connector C-114 (terminals 
3, 2, 5. 4 and 1).
Q: Are the wiring harness between A/C-ECU connector 

C-20 (terminal 29, 35, 36, 34 and 28) and air mixing 
damper control motor connector C-114 (terminals 3, 2, 
5. 4 and 1) in good condition?
YES : Go to Step 4.
NO :  Repair the wiring harness. Check that the A/C works 

normally. 

STEP 4. Replace the air mixing damper control motor and 
check the trouble symptom again
Check the trouble symptom again.
Q: Is the check result satisfactory?

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

AUTO A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55-98

INSPECTION PROCEDURE 8: Air Outlet Vent cannot be Changed.

.

CIRCUIT OPERATION

If the air outlet cannot be switched, the mode selection damper 
control motor circuit may be failed.

.

TROUBLESHOOTING HINTS

• Malfunction of the mode selection damper control motor

• Malfunction of the A/C-ECU

• Damaged harness wires or connectors

Mode Selection Damper Control Motor Circuit

MODE SELECTION 
DAMPER CONTROL 
MOTOR

A/C-ECU

AC708624

AC708951AT

C-20 (B)

Connectors: C-20, C-112

C-112