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.