INSPECTION PROCEDURE 6: The A/C compressor does not work


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?
Go to Step 2.
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?
Go to Step 3.
Refer to diagnosis code chart .

STEP 3. Voltage measurement at 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 and earth terminal 102.
(4)Voltage between terminal 1 and body earth.
OK: System voltage

Q. Is the check result normal?
Go to Step 4.
Go to Step 8.

STEP 4. Check the A/C compressor.
Refer to .

Q. Is the check result normal?
Go to Step 5.
Replace the A/C compressor.

STEP 5. Check the refrigerant temperature switch.
Refer to .

Q. Is the refrigerant temperature switch operating properly?
Go to Step 6.
Replace the refrigerant temperature switch.

STEP 6. Check the refrigerant level.
Refer to .

Q. Is the refrigerant level correct?
Go to Step 7.
Correct the refrigerant level (Refer to On-vehicle Service ).

STEP 7. Replace the A/C-ECU, and then recheck the trouble symptom
Check that the compressor works normally.

Q. Is the check result normal?
This diagnosis is complete.
Replace the engine-ECU (Refer to GROUP 13A - Engine-ECU <4B1> , GROUP 13C - Engine-ECU <4J1> and GROUP 13D - Engine-ECU <4N1>).

STEP 8. Check the A/C compressor relay
Refer to .

Q. Is the check result normal?
Go to Step 9.
Replace the A/C compressor relay.

STEP 9. 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?
Go to Step 11.
Go to Step 10.

STEP 10. Check of open circuit in A/C compressor relay power supply line between fusible link and A/C compressor relay connector.

Q. Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).
Repair the wiring harness.

STEP 11.Check of open circuit in A/C compressor relay power supply line between A/C compressor relay connector and A/C compressor assembly connector.
note Prior to the wiring harness inspection, check intermediate connector and repair if necessary.

Q. Is the check result normal?
Go to Step 12.
Repair the connector(s) or wiring harness.

STEP 12. Check of open circuit in AC/R line (engine-ECU) between A/C compressor relay connector and engine-ECU connector.
note Prior to the wiring harness inspection, check intermediate connector and repair if necessary <4N1>.

Q. Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).
Repair the connector(s) or wiring harness.