ECD SYSTEM (w/o DPF), Diagnostic DTC:P0400

DTC Code DTC Name
P0400 Exhaust Gas Recirculation Flow

DESCRIPTION

The EGR system recirculates exhaust gases, in order to suit every driving condition. The recirculated gas mingles with intake air, therefore the EGR system can slow combustion speed and keep the combustion temperature down. This helps reduce NOx emission.

In order to increase EGR circulation efficiency, the ECM adjusts the lift amount of the electric EGR control valve and throttle valve angle.

DTC No. DTC Detection Condition Trouble Area
P0400

When either condition below is met:


  • Target and actual positions of the electric EGR control valve are different

    (1 trip detection logic)

  • Mass air flow rate is not changed when turning on electric EGR control valve

    (2 trip detection logic)

  • Electric EGR control valve stuck

  • Electric EGR control valve does not move smoothly

  • E-VRV for EGR (electric EGR control valve assembly)

  • VSV for EGR cut

  • E-VRV for EGR circuit

  • VSV for EGR cut circuit

  • ECM

MONITOR DESCRIPTION


WIRING DIAGRAM

A01BFTYE01

INSPECTION PROCEDURE

Note

After replacing the ECM, the new ECM needs registration Click here and initialization Click here.

Tech Tips


  • Read freeze frame data using an intelligent tester. Freeze frame data record the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data, from the time the malfunction occurred.

  • DTC P0400 is set when the engine is warmed up, and 1 second or more passes after quickly accelerating the engine from idling.

PROCEDURE


  1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0400)


    1. Connect an intelligent tester to the DLC3.

    2. Turn the ignition switch to ON and turn the tester ON.

    3. Select the following menu items: Powertrain / Engine / DTC.

    4. Read DTCs.

      Result
      Display (DTC Output) Proceed To
      P0400 A
      P0400 and P0405 and/or P0406 B

      Tech Tips

      If any DTCs other than P0400 are output, troubleshoot those DTCs first.


    B

    GO TO DTC CHART

    A

  2. CHECK VACUUM PUMP ASSEMBLY


    1. Check the negative pressure of the vacuum pump.

      Standard
      More than 86.7 kPa (650 mmHg, 26 in.Hg)

    NG

    REPLACE VACUUM PUMP ASSEMBLY

    OK

  3. CHECK VACUUM HOSES


    1. Check the vacuum hoses.

      OK
      The hoses are not damaged and securely connected.

    NG

    REPAIR OR REPLACE VACUUM HOSE

    OK

  4. PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE EGR SYSTEM)

    A01BDB6E02

    1. Disconnect the vacuum hose from the electric EGR control valve.

    2. Connect the vacuum gauge to the E-VRV side vacuum hose.

    3. Connect an intelligent tester to the DLC3.

    4. Start the engine and turn the tester ON.

    5. Warm up the engine until the engine coolant temperature reaches 80°C (176°F).

    6. Select the following menu items: Powertrain / Engine / Active Test / Control the EGR System.

    7. Check the pressure variation when the E-VRV for EGR is turned from OFF to ON using the Active Test function.

      Result
      Active Test Vacuum Gauge Proceed To
      OFF to ON Pressure changes from 0 kPa (0 mmHg, 0 in.Hg) below -28 kPa (-210 mmHg, -8.3 in.Hg) A
      Pressure fixed at 0kPa (0 mmHg, 0 in.Hg), or above 28kPa (210 mmHg, 8.3 in.Hg) B

    8. Disconnect the vacuum gauge.

    9. Reconnect the vacuum hose to the electric EGR control valve.


    B

    INSPECT ELECTRIC EGR CONTROL VALVE ASSEMBLY (E-VRV FOR EGR) Click here

    A

  5. PERFORM ACTIVE TEST USING INTELLIGENT TESTER (ACTIVATE THE VSV FOR EGR CUT)

    A01BBTBE01

    1. Using a 3-way connector, connect a vacuum gauge to the hose between the VSV for EGR cut and electric EGR control valve assembly.

    2. Connect an intelligent tester to the DLC3.

    3. Start the engine and turn the tester ON.

    4. Select the following menu items: Powertrain / Engine / Active Test / Activate the VSV for EGR Cut.

    5. Check the pressure variation when the E-VRV for EGR is turned from OFF to ON using the Active Test function.

      Result
      Active Test Vacuum Gauge Proceed To
      OFF to ON Pressure changes from 0 kPa (0 mmHg, 0 in.Hg) below -28 kPa (-210 mmHg, -8.3 in.Hg) A
      Pressure fixed at 0kPa (0 mmHg, 0 in.Hg), or above 28kPa (210 mmHg, 8.3 in.Hg) B

    B

    INSPECT VACUUM SWITCHING VALVE (VSV FOR EGR CUT) Click here

    A

  6. INSPECT ELECTRIC EGR CONTROL VALVE ASSEMBLY (EGR VALVE OPERATION)

    Inspect the electric EGR control valve assembly Click here.

    OK
    The valve is not stuck and does not have heavy carbon deposits.

    NG

    REPLACE ELECTRIC EGR CONTROL VALVE ASSEMBLY

    OK

  7. CHECK FOR BLOCKAGE IN EGR GAS PASSAGE (EXHAUST MANIFOLD - ELECTRIC EGR CONTROL VALVE)


    1. Check for blockage in the EGR gas passage between the exhaust manifold and electric EGR control valve assembly.

      OK
      No blockage in the EGR gas passage

    NG

    REPAIR OR REPLACE MALFUNCTIONING PARTS, COMPONENT AND AREA

    OK

    REPLACE ECM

  8. INSPECT ELECTRIC EGR CONTROL VALVE ASSEMBLY (E-VRV FOR EGR)


    1. A01BH5EE13

      Disconnect the D55 E-VRV for EGR connector.

    2. Measure the resistance of the E-VRV for EGR.

      Standard resistance
      Tester Connection Specified Condition
      1 - 2

      11 to 13 Ω

      at 20°C (68°F)

    3. Reconnect the E-VRV for EGR connector.


    NG

    REPLACE ELECTRIC EGR CONTROL VALVE ASSEMBLY

    OK

  9. CHECK HARNESS AND CONNECTOR (E-VRV FOR EGR - ECM)


    1. A01BEXSE11

      Disconnect the D55 E-VRV for EGR connector.

    2. Disconnect the D3 ECM connector.

    3. Check the resistance.

      Standard resistance (Check for open)
      Tester Connection Specified Condition
      D55-2 - EGR (D3-9) Below 1 Ω
      Standard resistance (Check for short)
      Tester Connection Specified Condition
      D55-2 or EGR (D3-9) - Body ground 10 kΩ or higher

    4. Reconnect the ECM connector.

    5. Reconnect the E-VRV for EGR connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  10. CHECK HARNESS AND CONNECTOR (E-VRV FOR EGR - MAIN RELAY)


    1. A01BBUNE01

      Remove the integration relay (MAIN relay) from the No.1 engine room R/B and J/B.

    2. Disconnect the E-VRV for EGR connector.

    3. Check the resistance.

      Standard resistance (Check for open)
      Tester Connection Specified Condition
      Integration relay (1J-4) - D55-1 Below 1 Ω
      Standard resistance (Check for short)
      Tester Connection Specified Condition
      Integration relay (1J-4) or D55-1 - Body ground 10 kΩ or higher

    4. Reinstall the integration relay.

    5. Reconnect the E-VRV for EGR connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE ECM

  11. INSPECT VACUUM SWITCHING VALVE (VSV FOR EGR CUT)


    1. A01BGKAE02

      Disconnect the D68 VSV for EGR cut connector.

    2. Measure the resistance of the VSV for EGR cut.

      Standard resistance
      Tester Connection Specified Condition
      1 - 2

      37 to 44 Ω

      at 20°C (68°F)

    3. Reconnect the VSV for EGR cut connector.


    NG

    REPLACE VACUUM SWITCHING VALVE (VSV FOR EGR CUT)

    OK

  12. CHECK HARNESS AND CONNECTOR (VSV FOR EGR CUT - ECM)


    1. A01BG4IE03

      Disconnect the D68 VSV for EGR Cut connector.

    2. Disconnect the D3 ECM connector.

    3. Check the resistance.

      Standard resistance (Check for open)
      Tester Connection Specified Condition
      EGRC (D3-18) - D68-2 Below 1 Ω
      Standard resistance (Check for short)
      Tester Connection Specified Condition
      EGRC (D3-18) or D68-2 - Body ground 10 kΩ or higher

    4. Reconnect the ECM connector.

    5. Reconnect the VSV for EGR cut connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  13. CHECK HARNESS AND CONNECTOR (VSV FOR EGR CUT - MAIN RELAY)


    1. A01BFU3E01

      Remove the integration relay (MAIN relay) from the No.1 engine room R/B and J/B.

    2. Disconnect the VSV for EGR cut connector.

    3. Check the resistance.

      Standard resistance (Check for open)
      Tester Connection Specified Condition
      Integration relay (1J-4) - D68-1 Below 1 Ω
      Standard resistance (Check for short)
      Tester Connection Specified Condition
      Integration relay (1J-4) or D68-1 - Body ground 10 kΩ or higher

    4. Reinstall the integration relay.

    5. Reconnect the VSV for EGR cut connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE ECM