Mitsubishi Lancer Evolution IX. Manual - part 535

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-13

NOTE: 

Prior to the wiring harness inspection, check interme-
diate connector C-10, and repair if necessary.

• Check the sensor signal line and earth line for 

open or short circuit.

Q: Is the check result normal?

YES : 

Replace the automatic A/C control panel 

(A/C-ECU)

NO : 

Repair the wiring harness.

AC504617AF

Connector: C-10 <LHD>

AC504618AF

Connector: C-10 <RHD>

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-14

Code No.21, 22: Air Thermo Sensor System

<LHD>

<RHD>

Air Thermo Sensor Circuit

Wire colour code
B : Black     LG : Light green     G : Green     L : Blue     W : White     Y : Yellow     SB : Sky blue
BR : Brown     O : Orange     GR : Grey     R : Red     P : Pink     V : Violet     PU : Purple

AIR THERMO
SENSOR

A/C-ECU

Air Thermo Sensor Circuit

Wire colour code
B : Black     LG : Light green     G : Green     L : Blue     W : White     Y : Yellow     SB : Sky blue
BR : Brown     O : Orange     GR : Grey     R : Red     P : Pink     V : Violet     PU : Purple

HEATER WATER
TEMPERATURE
SENSOR

AIR THERMO
SENSOR

A/C-ECU

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-15

COMMENTS ON TROUBLE SYMPTOM

This code is set when the air thermo sensor circuit is 
open (Code No.21) or is short (Code No.22).

PROBABLE CAUSES

• Malfunction of the air thermo sensor

• Damaged the wiring harness or connectors

• Malfunction of the automatic A/C control panel 

(A/C-ECU)

DIAGNOSIS PROCEDURE

STEP 1. Check the air thermo sensor.
Refer to 

P.55-120

.

Q: Is the check result normal?

YES : 

Go to Step 2.

NO : 

Replace the air thermo sensor.

STEP 2. Connector check: C-36 A/C-ECU 
connector and C-35 air thermo sensor connector

Q: Is the check result normal?

YES : 

Go to Step 3.

NO : 

Repair the connector.

AC504617AD

Connector: C-35 <LHD>

Harness side

AC504624AC

Connectors: C-35, C-36 <RHD>

Harness side

C-35

C-36 (B)

C-35

C-36

AC504622AB

Connector: C-36 <LHD>

Harness side

C-36 (B)

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-16

STEP 3. Check the wiring harness between C-36 
A/C-ECU connector (terminals 8 and 20) and C-35 
air thermo sensor connector (terminals 1 and 2).

NOTE: 

Prior to the wiring harness inspection, check interme-
diate connector C-10 and heater water temperature 
sensor connector C-32 <RH drive vehicles>, and 
repair if necessary.

• Check the sensor signal line and earth line for 

open or short circuit.

Q: Is the check result normal?

YES : 

Replace the automatic A/C control panel 

(A/C-ECU)

NO : 

Repair the wiring harness.

AC504617AD

Connector: C-35 <LHD>

Harness side

AC504624AC

Connectors: C-35, C-36 <RHD>

Harness side

C-35

C-36 (B)

C-35

C-36

AC504622AB

Connector: C-36 <LHD>

Harness side

C-36 (B)

AC504617AF

Connector: C-10 <LHD>

AC504618AF

Connector: C-10 <RHD>

AC504618AL

Connector: C-32 <RHD>

Harness side