Code No. P0401: Exhaust Gas Recirculation Flow Insufficient <Euro5b>


OPERATION



  • Refer to Code No. P0102: Air Flow Sensor Circuit Low Input .
  • Refer to Code No. P0403: Exhaust Gas Recirculation Valve DC Motor Malfunction .
  • Refer to Code No. P0489: Exhaust Gas Recirculation Valve Position Sensor Circuit Low Input <Euro5> .

FUNCTION



  • The engine-ECU monitors the exhaust gas recirculation flow rate.

TROUBLE JUDGMENT


Check Conditions
  • Engine is running
  • Battery positive voltage is 8 - 16 V.
  • Normal running (vehicle speed: 65 - 75 km/h, transmission: 5th)
  • The intake air temperature is from 20 to 40 °C.
Judgment Criterion
  • The exhaust gas recirculation flow rate is larger than target exhaust gas recirculation flow rate by the rate that is more than the specified value.

PROBABLE CAUSES



  • Failed exhaust gas recirculation passage (leakage and clogged exhaust gas recirculation passage)
  • Harness damage in exhaust gas recirculation valve circuit or loose connector contact
  • Failed exhaust gas recirculation valve operation
  • Harness damage in air flow sensor circuit or loose connector contact
  • Failed air flow sensor (abnormal output characteristics)
  • Failed engine-ECU

DIAGNOSTIC PROCEDURE

STEP 1. M.U.T.-III diagnosis code

Q. Is the diagnosis code P0403 or P2413 set?
Inspection chart for diagnosis codes (Refer to ).
Go to Step 2.

STEP 2. Connector check: B-02 exhaust gas recirculation valve assembly connector

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

STEP 3. Connector check: D-213 and D-215 engine-ECU connectors

Q. Is the check result normal?
Go to Step 4.
Repair or replace the connector.

STEP 4. Check harness between D-215 (terminal No. 115) engine-ECU connector and B-02 (terminal No. 6) exhaust gas recirculation valve assembly connector.

  • Check output line for damage.

Q. Is the check result normal?
Go to Step 5.
Repair the damaged harness wire.

STEP 5. Check harness between D-215 (terminal No. 130) engine-ECU connector and B-02 (terminal No. 4) exhaust gas recirculation valve assembly connector.

  • Check output line for damage.

Q. Is the check result normal?
Go to Step 6.
Repair the damaged harness wire.

STEP 6. Check harness between D-213 (terminal No. 81) engine-ECU connector and B-02 (terminal No. 2) exhaust gas recirculation valve assembly connector.

  • Check earthing line for damage.

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

STEP 7. Check harness between D-213 (terminal No. 71) engine-ECU connector and B-02 (terminal No. 3) exhaust gas recirculation valve assembly connector.

  • Check power supply line for damage.

Q. Is the check result normal?
Go to Step 8.
Repair the damaged harness wire.

STEP 8. Check harness between D-213 (terminal No. 57) engine-ECU connector and B-02 (terminal No. 1) exhaust gas recirculation valve assembly connector.

  • Check output line for damage.

Q. Is the check result normal?
Go to Step 9.
Repair the damaged harness wire.

STEP 9. Check exhaust gas recirculation valve itself.

  • Check EGR valve itself [Refer to GROUP 17 - Emission Control <4M4> - Exhaust Gas Recirculation (EGR) System - Exhaust Gas Recirculation Valve (DC motor) Check ].

Q. Is the check result normal?
Go to Step 10.
Replace the exhaust gas recirculation valve assembly.

STEP 10. Check exhaust gas recirculation passage for deposits.

  • Check the exhaust gas recirculation valve, the exhaust gas recirculation valve pipe and the inside of the exhaust gas recirculation cooler for deposits. (Refer to GROUP 17 - Emission Control <4M4> - EGR Valve And EGR Cooler - Removal And Installation <Emission regulation step V> ).

Q. Is the check result normal?
Go to Step 11.
Cleaning or replace the exhaust gas recirculation valve, exhaust gas recirculation valve pipe and exhaust gas recirculation cooler.

STEP 11. Connector check: B-32 air flow sensor connector.

Q. Is the check result normal?
Go to Step 12.
Repair or replace the connector.

STEP 12. Check harness between B-32 (terminal No. 4) air flow sensor connector and D-215 (terminal No. 155) engine-ECU connector.

  • Check earthing line for damage.

Q. Is the check result normal?
Go to Step 13.
Repair the damaged harness wire.

STEP 13. Check harness between B-32 (terminal No. 3) air flow sensor connector and D-215 (terminal No. 140) engine-ECU connector.

  • Check output line for damage.

Q. Is the check result normal?
Go to Step 14.
Repair the damaged harness wire.

STEP 14. Replace the air flow sensor.

  • After replacing the air flow sensor, re-check the trouble symptoms.

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 ).