Inspection Procedure 25: A/C load signal system








OPERATION



PROBABLE CAUSES



DIAGNOSIS PROCEDURE

STEP 1. Perform voltage measurement at D-213 engine-ECU connector.

  • Measure engine-ECU terminal voltage.
  • Engine: Idling
  • A/C switch: ON (A/C compressor in driven state)
  • Voltage between terminal No. 13 and earth.
OK:
    1 V or less (when the temperate around the atmospheric air temperature sensor is 18°C or more, and the A/C is set to the lowest temperature and the maximum air flow rate)
    System voltage (when the A/C is set to the temperature in the cabin and the minimum air flow rate)

Q. Is the check result normal?
Go to Step 2.
Go to Step 4.

STEP 2. Connector check: D-213 engine-ECU connector

Q. Is the check result normal?
Go to Step 3.
Repair or replace.

STEP 3. Check the trouble symptoms.

Q. Does trouble symptom persist?
Replace the engine-ECU. When the engine-ECU is replaced, write the chassis number (Refer to GROUP 00 - Precautions Before Service - How to Perform Chassis Number Writing ). After replacing the engine-ECU, register the injector identification code and learn fuel injection. (Refer to GROUP 00 - Precautions Before Service - What The Common Rail Engine Learns ).
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

STEP 4. Connector check: D-213 engine-ECU connector


Q. Is the check result normal?
Go to Step 5.
Repair or replace.

STEP 5. Perform voltage measurement at D-08 A/C-ECU connector.

  • Measure A/C-ECU terminal voltage.
  • Engine: Idling

  • A/C set temperature:

      • Maximum Cool when temperature in cabin is 25°C or more
      Maximum Hot when temperature in cabin is 25°C or less
  • Voltage between terminal No. 12 and earth.
OK: System voltage

Q. Is the check result normal?
Go to Step 8.
Go to Step 6.

STEP 6. Connector Check: D-08 A/C-ECU connector

Q. Is the check result normal?
Go to Step 7.
Repair or replace.

STEP 7. Check harness between D-08 (terminal No. 12) A/C-ECU connector and D-213 (terminal No. 13) engine-ECU connector.
note Before checking harness, check intermediate connector D-230, and repair if necessary.

  • Check output line for short circuit.

Q. Is the check result normal?
Check A/C system (Refer to GROUP 55 - Troubleshooting - Check Chart for Trouble Symptoms ).
Repair the harness wire.

STEP 8. Connector check: D-08 A/C-ECU connector

Q. Is the check result normal?

  • Check intermediate connector D-230, and repair if necessary. If intermediate connector is normal, check and repair harness between D-08 (terminal No. 12) A/C-ECU connector and D-213 (terminal No. 13) engine-ECU connector.

    • Check output line for open circuit.
Repair or replace.