Inspection Procedure 21: EGR Cooler Solenoid Valve System










OPERATION



  • Power is supplied to the EGR cooler solenoid valve (terminal No. 2) from the engine control relay (terminal No. 2).
  • The engine-ECU (terminal No. 60) makes the power transistor in the unit be in "ON" position, and that makes currents go on the EGR cooler solenoid valve (terminal No. 1).

FUNCTION



  • In response to a signal from the engine-ECU, the EGR cooler solenoid valve controls the operation of the exhaust flap.

PROBABLE CAUSES



  • Failed EGR cooler solenoid valve
  • Open/short circuit or harness damage in EGR cooler solenoid valve circuit or loose connector contact
  • Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. Connector check: B-23 EGR cooler solenoid valve connector

Q. Is the check result normal?
Go to Step 2 .
Repair or replace the connector.

STEP 2. Perform voltage measurement at B-23 EGR cooler solenoid valve connector.

  • Disconnect connector, and measure at the harness side.
  • Ignition switch: ON
  • Voltage between terminal No. 2 and earth.
OK: System voltage

Q. Is the check result normal?
Go to Step 4 .
Go to Step 3 .

STEP 3. Connector check: A-33X engine control relay connector

Q. Is the check result normal?

    Check intermediate connector A-11, and repair if necessary. If intermediate connector is normal, check and repair harness between B-23 (terminal No. 2) EGR cooler solenoid valve connector and A-33X (terminal No. 2) engine control relay connector.

    • Check power supply line for open/short circuit.
Repair or replace the connector.

STEP 4. Perform voltage measurement at B-27 engine-ECU connector.

  • Disconnect connector, and measure at the harness side.
  • Ignition switch: ON
  • Voltage between terminal No. 60 and earth.
OK: System voltage

Q. Is the check result normal?
Go to Step 8 .
Go to Step 5 .

STEP 5. Connector check: B-27 engine-ECU connector

Q. Is the check result normal?
Go to Step 6 .
Repair or replace the connector.

STEP 6. Check harness between B-23 (terminal No. 1) EGR cooler solenoid valve connector and B-27 (terminal No. 60) engine-ECU connector.

  • Check earthing line for open/short.

Q. Is the check result normal?
Go to Step 7 .
Repair the damaged harness wire.

STEP 7. Check the trouble symptoms.

Q. Does trouble symptom persist?

Replace the EGR cooler solenoid valve.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

STEP 8. Connector check: B-27 engine-ECU connector

Q. Is the check result normal?
Go to Step 9 .
Repair or replace the connector.

STEP 9. Check harness between B-23 (terminal No. 1) EGR cooler solenoid valve connector and B-27 (terminal No. 60) engine-ECU connector.

  • Check earthing line for damage.

Q. Is the check result normal?
Go to Step 10 .
Repair the damaged harness wire.

STEP 10. Check harness between B-23 (terminal No. 2) EGR cooler solenoid valve connector and A-33X (terminal No. 2) engine control relay connector.
note Before checking harness, check intermediate connector A-11, and repair if necessary.

  • Check power line for damage.

Q. Is the check result normal?
Go to Step 11 .
Repair the damaged harness wire.

STEP 11. Replace the EGR cooler solenoid valve.

  • After replacing the EGR cooler solenoid valve, re-check the trouble symptoms.

Q. Does trouble symptom persist?

Replace the engine-ECU.
The check is end.