Mitsubishi Lancer (4A9 engine). Manual - part 295

 

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Mitsubishi Lancer (4A9 engine). Manual - part 295

 

 

AC612690

AE

Connector: A-11

AC605626

AC613229

AB

Connector: A-14X

A-14X

AC612696

Connector: B-09  

AB

ACB02650

AB

B-113 (B)

Connector: B-113 <1600>

ACB02652

AB

B-113 (B)

Connector: B-113 <Except 1600>

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55A-61

COMMENTS ON TROUBLE SYMPTOM
When the A/C compressor does not work, the A/C 
compressor circuit system may be defective.

PROBABLE CAUSES

• Malfunction of the A/C compressor

• Malfunction of the A/C compressor relay

• Damaged harness wires or connectors

• Malfunction of the engine-ECU

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 .

STEP 3. Connector check: B-113 A/C compressor 
assembly connector and B-09 engine-ECU 
connector

Q: Is the check result normal?

YES : 

Go to Step 4.

NO : 

Repair the connector.

STEP 4. Voltage measurement at B-113 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 B-09 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 5.

NO : 

Go to Step 9.

STEP 5. Check the A/C compressor.
Refer to .

Q: Is the check result normal?

YES : 

Go to Step 6.

NO : 

Replace the A/C compressor.

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55A-62

STEP 6. Check the refrigerant temperature 
switch.
Refer to .

Q: Is the refrigerant temperature switch operating 

properly?
YES : 

Go to Step 7.

NO : 

Replace the refrigerant temperature switch.

STEP 7. Check the refrigerant level.
Refer to .

Q: Is the refrigerant level correct?

YES : 

Go to Step 8.

NO : 

Correct the refrigerant level (Refer to On-
vehicle Service ).

STEP 8. 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, and then register 
the ID code (Refer to GROUP 42B 
Troubleshooting 

− ID code registration 

judgement table  <Vehicles with KOS> or 
GROUP 42C Troubleshooting 

− ID code 

registration judgement table  <Vehicles 
without KOS>).

STEP 9. Connector check: A-14X A/C 
compressor relay connector

Q: Is the check result normal?

YES : 

Go to Step 10.

NO : 

Repair the connector.

STEP 10. Check the A/C compressor relay
Refer to .

Q: Is the check result normal?

YES : 

Go to Step 11.

NO : 

Replace the A/C compressor relay.

STEP 11. 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 13.

NO : 

Go to Step 12.

STEP 12. Check the wiring harness between A-
14X A/C compressor relay connector terminal 
No.2, 4 and the fusible link (36).

• Check the A/C compressor relay power supply 

line for open circuit.

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 13. Check the wiring harness between A-
14X A/C compressor relay connector terminal 
No.3 and B-113 A/C compressor assembly 
connector terminal No.1.

• Check the A/C compressor power supply line for 

open circuit.

NOTE: Prior to the wiring harness inspection, check 
intermediate connectors A-11 and repair if neces-
sary.

Q: Is the check result normal?

YES : 

Go to Step 14.

NO : 

Repair the wiring harness.

STEP 14. Check the wiring harness between A-
14X A/C compressor relay connector terminal 
No.1 and B-09 engine-ECU connector terminal 
No.102.

• Check the A/C compressor relay power supply 

line for open circuit.

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.

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55A-63

INSPECTION PROCEDURE 7: The A/C compressor does not work <Diesel engine>

A/C Compressor Assembly Circuit <Diesel engine>

A/C
COMPRESSOR
RELAY

A/C
COMPRESSOR
ASSEMBLY

A/C
REFRIGERANT
TEMPERATURE
SWITCH

A/C
COMPRESSOR
CLUTCH

ENGINE-ECU

RELAY
BOX

FUSIBLE
LINK

38

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     SI : Silver

ACB02704

AC612690

AE

Connector: A-11

AC605626

AC613229

AB

Connector: A-14X

A-14X

AC809224

Connectors: B-39

AD

B-39 (B)

AC612697

AB

B-113 (B)

Connector: B-113

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55A-64

COMMENTS ON TROUBLE SYMPTOM
When the A/C compressor does not work, the A/C 
compressor circuit system may be defective.

PROBABLE CAUSES

• Malfunction of the A/C compressor

• Malfunction of the A/C compressor relay

• Damaged harness wires or connectors

• Malfunction of the engine-ECU

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 .

STEP 3. Connector check: B-113 A/C compressor 
assembly connector and B-39 engine-ECU 
connector

Q: Is the check result normal?

YES : 

Go to Step 4.

NO : 

Repair the connector.

STEP 4. Voltage measurement at B-113 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 B-39 and 

earth terminal 19.

(4) Voltage between terminal 1 and body earth.

OK: System voltage

Q: Is the check result normal?

YES : 

Go to Step 5.

NO : 

Go to Step 9.

STEP 5. Check the A/C compressor.
Refer to .

Q: Is the check result normal?

YES : 

Go to Step 6.

NO : 

Replace the A/C compressor.

STEP 6. Check the refrigerant temperature 
switch.
Refer to .

Q: Is the refrigerant temperature switch operating 

properly?
YES : 

Go to Step 7.

NO : 

Replace the refrigerant temperature switch.

 

 

 

 

 

 

 

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