Mitsubishi Grandis. Manual - part 314

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-141

NOTE: Prior to the wiring harness inspection, check 
intermediate connector C-128, and repair if 
necessary.

• Check the input line for open circuit.

Q: Is the check result normal?

YES : 

Go to Step 8.

NO : 

Repair the wiring harness.

STEP 8. Recheck the trouble symptom

Q: Is the check result normal?

YES : 

The trouble can be an intermittent 

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

P.00-5

).

NO : 

Replace the A/C-ECU.

AC310614

BC

Connectors: C-106, C-128 <LHD>

Harness side

C-106

C-128

C-106

C-128

AC310632AW

Connectors: C-106, C-128 <RHD>

Harness side

C-106

C-128

C-106

C-128

AC310649

AB

Connector: E-03 <LHD>             

Harness side

AC310653

AB

Connector: E-03 <RHD>             

Harness side

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-142

INSPECTION PROCEDURE 18: A/C pressure sensor system <LHD>

COMMENTS ON TROUBLE SYMPTOM

If the A/C pressure sensor is defective, the damaged 
wiring harness between the A/C pressure sensor and 
the A/C-ECU may be suspected.

POSSIBLE CAUSES

• Malfunction of A/C pressure sensor

• Malfunction of the A/C-ECU

• Damaged harness wires and connectors

Step 1. MUT-III data list

Check that the following service data display 
contents are normal. (Refer to 

P.55-183

.)

• Item 04: Pressure sensor

Q:  Is the check result normal?

YES : 

Go to Step 6.

NO  : 

Go to Step 2.

Step 2. Connector check: A-37 A/C pressure 
sensor connector

Q:  Is the check result normal?

YES : 

Go to Step 3.

NO : 

Repair the connector.

Step 3. Inspection of A/C pressure sensor

 Refer to 

P.55-195

.

Q:  Is the check result normal?

YES : 

Go to Step 4.

NO : 

Replace the A/C pressure sensor.

A/C PRESSURE
SENSOR

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

A/C-ECU

A/C Pressure Sensor

AC310401

Connector: A-37 <LHD>

Harness side

AJ

A-37 (B)

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-143

Step 4. Connector check: C-106 A/C-ECU 
connector

Q:  Is the check result normal?

YES : 

Go to Step 5.

NO : 

Repair the connector.

Step 5. Check the wiring harness between A-37 
A/C pressure sensor connector (terminals 2, 1 
and 3) and C-106 A/C-ECU connector (terminals 
25, 14 and 1).

NOTE: Prior to the wiring harness inspection, check 
intermediate connector C-125 and joint connector 
C-01, and repair if necessary.

• Check the input line for open circuit.

Q: Is the check result normal?

YES : 

Go to Step 6.

NO : 

Repair the wiring harness.

STEP 6. Recheck the trouble symptom

Q: Is the check result normal?

YES : 

The trouble can be an intermittent 

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

P.00-5

).

NO : 

Replace the A/C-ECU.

AC310613

AB

Connector: C-106 <LHD>

Harness side

AC310401

Connector: A-37 <LHD>

Harness side

AJ

A-37 (B)

AC310614

AD

Connectors: C-01, C-106, C-125 <LHD>

C-106

C-125

C-106

Harness side

C-125

C-01

C-01

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-144

INSPECTION PROCEDURE 19: A/C pressure sensor system <RHD>

COMMENTS ON TROUBLE SYMPTOM

If the A/C pressure sensor is defective, the damaged 
wiring harness between the A/C pressure sensor and 
the A/C-ECU may be suspected.

POSSIBLE CAUSES

• Malfunction of A/C pressure sensor

• Malfunction of the A/C-ECU

• Damaged harness wires and connectors

Step 1. MUT-III data list

Check that the following service data display 
contents are normal. (Refer to 

P.55-183

.)

• Item 04: Pressure sensor

Q:  Is the check result normal?

YES : 

Go to Step 6.

NO  : 

Go to Step 2.

Step 2. Connector check: A-37 A/C pressure 
sensor connector

Q:  Is the check result normal?

YES : 

Go to Step 3.

NO : 

Repair the connector.

Step 3. Inspection of A/C pressure sensor

 Refer to 

P.55-195

.

Q:  Is the check result normal?

YES : 

Go to Step 4.

NO : 

Replace the A/C pressure sensor.

A/C-ECU

IGNITION 
SWITCH (IG2)

MOTOR DRIVE 
CIRCUIT

OUTSIDE/INSIDE AIR 
SELECTION DAMPER 
CONTROL MOTOR

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

Outside/Inside Air Selection Damper Control Motor Circuit

AC310396

Connector: A-37 <RHD>

Harness side

AI

A-37 (B)