Code No. P0402: EGR Flow Excessive <Euro5b>


OPERATION



  • Refer to Code No. P0102: Air Flow Sensor Circuit Low Input .
  • Refer to Code No. P0403: EGR Valve (DC Motor) Malfunction .
  • Refer to Code No. P0489: EGR Valve Position Sensor Circuit Low Input <Euro5b> .

FUNCTION



  • The engine-ECU monitors the EGR flow rate.

TROUBLE JUDGMENT


Check Conditions
  • Engine is running
  • Battery positive voltage is 8 - 16 V.
  • Vehicle is stopped (transmission: Neutral <M/T>, P range <A/T>)
Judgment Criterion
  • The EGR flow rate is smaller than target EGR flow rate by the rate that is more than the specified value.

PROBABLE CAUSES



  • Failed EGR passage (air suction)
  • Harness damage in EGR valve circuit or loose connector contact
  • Failed EGR 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: A-45 EGR valve assembly connector

Q. Is the check result normal?

Go to Step 3.

Repair or replace the connector.

STEP 3. Connector check: C-103 and C-105 engine-ECU connectors

Q. Is the check result normal?

Go to Step 4.

Repair or replace the connector.

STEP 4. Check harness between C-103 (terminal No. 115) engine-ECU connector and A-45 (terminal No. 6) EGR 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 C-103 (terminal No. 130) engine-ECU connector and A-45 (terminal No. 4) EGR 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 C-105 (terminal No. 81) engine-ECU connector and A-45 (terminal No. 2) EGR 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 C-105 (terminal No. 71) engine-ECU connector and A-45 (terminal No. 3) EGR 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 C-105 (terminal No. 57) engine-ECU connector and A-45 (terminal No. 1) EGR 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 EGR valve itself.

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

Q. Is the check result normal?
Go to Step 10.
Replace the EGR valve assembly.

STEP 10. Check EGR passage for air suction.

  • Check the EGR valve, the EGR pipe and the EGR cooler for the air suction.

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

STEP 11. Connector check: A-135 air flow sensor connector

Q. Is the check result normal?

Go to Step 12.

Repair or replace the connector.

STEP 12. Check harness between A-135 (terminal No. 4) air flow sensor connector and C-103 (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 A-135 (terminal No. 3) air flow sensor connector and C-103 (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, carry out the forcible DPF regeneration. (Refer to GROUP 17 - Emission Control - Diesel Particulate Filter (DPF) System - Forcible DPF Regeneration ).