ECD SYSTEM, Diagnostic DTC:P0400/71

DTC Code DTC Name
P0400/71 Exhaust Gas Recirculation Flow

DESCRIPTION

The EGR system recirculates exhaust gases, and is controlled to the proper volume to be suitable for all driving conditions. The recirculated gas mixes with the intake air, allowing the EGR system to slow down engine combustion and lower the combustion temperature. This helps reduce NOx emissions.

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

DTC No. DTC Detection Condition Trouble Area
P0400/71

  • Difference between target and actual position of EGR valve is 10 % or more for 10 seconds or more

    (1 trip detection logic)

  • Difference between target and actual position of EGR valve is 25 % or more for 3 seconds or more

    (1 trip detection logic)

  • EGR valve stuck

  • EGR valve does not move smoothly

  • Open or short in E-VRV for EGR circuit

  • Open or short in EGR valve position sensor circuit

  • EGR valve position sensor

  • Vacuum pump

  • Vacuum hose connection loose

  • ECM

Tech Tips

DTC detection is not performed for 4 seconds after brake switch is turned ON or OFF.

MONITOR DESCRIPTION

When the target and actual positions of the EGR valve are different, the ECM interprets this as a malfunction of the EGR valve and illuminates the MIL.

A01BFIKE01

WIRING DIAGRAM

A01BDCQE01

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 the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, if the engine was warmed up or not, and other data from the time the malfunction occurred.

  • After warming up the engine, DTC P0400/71 is set 1 second or more after quickly accelerating the engine from idling.

PROCEDURE


  1. CHECK OTHER DTC OUTPUT


    1. Connect the intelligent tester to the DLC3.

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

    3. Enter the following menus: Powertrain / Engine / DTC.

    4. Read DTCs.

      Result
      Display (DTC output) Proceed to
      P0400/71 A
      P0400/71 and P0405/96 and/or P0406/96 B

      Tech Tips

      If any other codes besides DTC P0400/71 are output, perform troubleshooting for those DTCs first.


    B

    GO TO DTC CHART

    A

  2. CHECK VACUUM PUMP ASSEMBLY


    1. Check the negative pressure of the vacuum pump. Click here

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

    NG

    REPLACE VACUUM HOSE 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. CHECK ECM TERMINAL VOLTAGE (EGR TERMINAL)


    1. A01BA46E01

      While idling the engine, check the waveform of the ECM connector.

      Standard
      Tester Connection Specified Condition
      D3-9 (EGR) - D3-7 (E1) Correct waveform is shown
      Tool Setting 2 V/DIV., 1 msec./DIV.
      Condition Idling with warm engine

      Tech Tips

      The waveform changes depending on the electric vacuum regulating valve for EGR operation.

      Note

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


    NG

    REPLACE ECM

    OK

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


    1. A01BH5EE01

      Disconnect the D55 E-VRV for EGR connector.

    2. Measure the resistance of the E-VRV.

      Standard resistance
      Tester Connection Condition Specified Condition
      1 - 2 20°C (68°F) 11 to 13 Ω

    NG

    REPLACE ELECTRIC EGR CONTROL VALVE ASSEMBLY

    OK

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


    1. A01BEXSE01

      Disconnect the D55 E-VRV for EGR connector.

    2. Disconnect the D3 ECM connector.

    3. Measure the resistance of the wire harness side connectors.

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

    NG

    REPAIR OR REPLACE HARNESS AND CONNECTOR

    OK

  7. CHECK HARNESS AND CONNECTOR (E-VRV FOR EGR - INTEGRATION RELAY)


    1. A01BF2LE01

      Remove the integration relay from the engine room J/B.

    2. Disconnect the 1J integration relay connector.

    3. Disconnect the D55 E-VRV connector.

    4. Measure the resistance of the wire harness side connectors.

      Standard resistance
      Tester Connection Specified Condition
      1J-5 - D55-1 Below 1 Ω
      1J-5 or D55-1 - Body ground 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS AND CONNECTOR

    OK

  8. INSPECT ELECTRIC EGR CONTROL VALVE ASSEMBLY (EGR VALVE ASSEMBLY)


    1. Check the EGR 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

    REPLACE ECM