ECD SYSTEM, 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 the intake air, therefore the EGR system can slow combustion speed and keep the combustion temperature down. This helps reduce NOx emissions.

In order to increase EGR circulation efficiency, the ECM adjusts the lift amount of the EGR valve and intake shutter valve angle (throttle valve).

DTC No. DTC Detection Condition Trouble Area
P0400 Open or short in EGR valve circuit

  • Open or short in EGR valve circuit

  • EGR valve

  • ECM

WIRING DIAGRAM

A01CH1WE01

INSPECTION PROCEDURE

Note

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

PROCEDURE


  1. INSPECT EGR VALVE ASSEMBLY (RESISTANCE)


    1. A01CH6PE04

      Disconnect the EGR valve connector.

    2. Measure the resistance according to the value(s) in the table below.

      Standard resistance
      Tester Connection Condition Specified Condition
      E17-1 (EGR) - E17-5 (+B) 20°C (68°F) 25.5 to 29.5 Ω

    3. Reconnect the EGR valve connector.


    NG

    REPLACE EGR VALVE ASSEMBLY Click here

    OK

  2. CHECK EGR VALVE ASSEMBLY (EGR VALVE POWER SOURCE)


    1. A01CIS0E04

      Disconnect the EGR valve connector.

    2. Turn the ignition switch to the ON position.

    3. Measure the voltage according to the value(s) in the table below.

      Standard voltage
      Tester Connection Condition Specified Condition
      E17-5 (VC) - Body ground Ignition switch in the ON position 18 to 27 V

    4. Reconnect the EGR valve connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (EGR VALVE POSITION SENSOR - MAIN RELAY)

    OK

  3. CHECK HARNESS AND CONNECTOR (EGR VALVE - ECM)


    1. A01CHL6E02

      Disconnect the EGR valve position sensor.

    2. Disconnect the ECM connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard resistance
      Check for open
      Tester Connection Condition Specified Condition
      E23-3 (EGRS) - E17-1 (EGR) Always Below 1 Ω
      Check for short
      Tester Connection Condition Specified Condition
      E23-3 (EGRS) or E17-1 (EGR) - Body ground Always 10 kΩ or higher

    4. Reconnect the EGR valve connector.

    5. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (EGR VALVE - ECM)

    OK

    REPLACE ECM