Code No. P2426: EGR Cooling Valve Control Circuit (low) <Euro5b>










OPERATION



  • Power is supplied to the EGR cooler bypass valve solenoid valve (terminal No. 2) from the engine control relay (terminal No. 1).
  • The engine-ECU (terminal No. 22) makes the power transistor in the unit be in "ON" position, and that makes currents go on the EGR cooler bypass valve solenoid valve (terminal No. 1).

FUNCTION



  • By the signals from the engine-ECU, the EGR cooler bypass valve solenoid valve takes control switching the pressure in the vacuum pump between the vacuum pressure and the atmospheric pressure.

TROUBLE JUDGMENT


Check Conditions
  • Battery positive voltage is 8 - 16 V.
  • 2 seconds later after the ignition switch has been in "ON" position or the engine has started up.
  • Engine coolant temperature is 35°C or lower.
  • The injector does not work.
Judgment Criterion
  • When the ECU command is "OPEN" and the valve position judged by the terminal voltage is "CLOSED".

PROBABLE CAUSES



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

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III actuator test

  • Item 32: EGR cooler bypass valve solenoid valve
OK: Operating sound can be heard and the valve vibrates

Q. Is the check result normal?
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).
Go to Step 2.

STEP 2. Connector check: B-138 EGR cooler bypass valve solenoid valve connector

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

STEP 3. Perform resistance measurement at B-138 EGR cooler bypass valve solenoid valve connector.

  • Disconnect connector, and measure at solenoid valve side.
  • Resistance between terminal No. 1 and No. 2.
OK: 29 - 35 Ω (at 20°C)

Q. Is the check result normal?
Go to Step 4.
Replace the EGR cooler bypass valve solenoid valve.

STEP 4. Perform voltage measurement at B-138 EGR cooler bypass valve solenoid valve connector.

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

Q. Is the check result normal?
Go to Step 6.
Go to Step 5.

STEP 5. Connector check: B-15X engine control relay connector

Q. Is the check result normal?

    Check intermediate connectors D-111 and D-113, and repair if necessary. If intermediate connectors are normal, check and repair harness between B-138 (terminal No. 2) EGR cooler bypass valve solenoid valve connector and B-15X (terminal No. 1) engine control relay connector.

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

STEP 6. Perform voltage measurement at D-213 engine-ECU connector.

  • Disconnect connector, and measure at harness side.
  • Ignition switch: ON
  • Voltage between terminal No. 22 and earth.
OK: System voltage

Q. Is the check result normal?
Go to Step 8.
Go to Step 7.

STEP 7. Connector check: D-213 engine-ECU connector

Q. Is the check result normal?

    Check and repair harness between B-138 (terminal No. 1) EGR cooler bypass valve solenoid valve connector and D-213 (terminal No. 22) engine-ECU connector.

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

STEP 8. Connector check: D-213 engine-ECU connector

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

STEP 9. Check harness between B-138 (terminal No. 1) EGR cooler bypass valve solenoid valve connector and D-213 (terminal No. 22) engine-ECU connector.

  • Check output line for damage.

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

STEP 10. Check harness between B-138 (terminal No. 2) EGR cooler bypass valve solenoid valve connector and B-15X (terminal No. 1) engine control relay connector.
note Before checking harness, check intermediate connectors D-111 and D-113, and repair if necessary.

  • Check power supply line for damage.

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

STEP 11. M.U.T.-III actuator test

  • Item 32: EGR cooler bypass valve solenoid valve
OK: Operating sound can be heard and the valve vibrates

Q. Is the check result normal?
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).
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 ). After registering the injector identification code, the vehicle equipped with the closed type DPF carries out the forcible DPF regeneration. (Refer to GROUP 17 - Diesel Particulate Filter (DPF) System - Forcible DPF Regeneration ).