SFI SYSTEM, Diagnostic DTC:P0400

DTC Code DTC Name
P0400 Exhaust Gas Recirculation Flow

DESCRIPTION

The EGR (Exhaust Gas Recirculation) system recirculates exhaust gases, which are controlled to the proper volume in accordance with driving conditions. The recirculated gas mingles with the intake air, therefore slowing down the engine combustion and lowering the combustion temperature. This helps reduce nitrogen oxide (NOx) emissions.

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

DTC No. DTC Detection Condition Trouble Area
P0400

Target and actual manifold absolute pressure rates differ

(3 trip detection logic)

  • Open or short in EGR valve circuit

  • EGR valve assembly

  • EGR passage

  • Manifold absolute pressure sensor

  • ECM

Tech Tips


  • DTC P0400 is stored while the engine is in fuel cut condition and the brake pedal is pressed for 7 seconds.

  • If DTC P0403 has already been stored, P0400 is not stored.

WIRING DIAGRAM

A01VEROE01

CAUTION / NOTICE / HINT

Note


  • Perform electronic throttle learning after replacing the ECM Click here.

  • Inspect the fuses for circuits related to this system before performing the following inspection procedure.

Tech Tips

Read freeze frame data using the intelligent tester. Freeze frame data records 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.

PROCEDURE


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


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the tester on.

    4. Enter the following menus: Powertrain / Engine and ECT / DTC.

    5. Read DTC.

      Result
      Result Proceed to
      DTC P0400 is output A
      DTC P0400 and P0403 is output B

    B

    CHECK EGR VALVE CIRCUIT Click here

    A

  2. PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE EGR STEP POSITION)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the tester on.

    4. Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher.

      Tech Tips


      • When performing the Active Test, make sure the shift lever is in Neutral position.

      • The A/C switch and all accessory switches should be off.

    5. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the EGR Step Position.

    6. Confirm that Throttle Idle Position is ON and check the engine idling condition and the value of MAP in the Data List while performing the Active Test.

      Tech Tips


      • Do not leave the EGR valve open for 10 seconds or more during the Active Test.

      • Be sure to return the EGR valve to step 0 when the Active Test is completed.

      OK
      MAP and idling condition change in response to EGR step position as follows.
      Standard
      - EGR Step Position (Active Test)
      0 Steps 0 to 30 Steps 30 to 40 Steps or Higher
      Idling condition Steady idling Idling changes from steady to rough idling or engine stalls Engine changes from rough idling to engine stall

      MAP value

      (Data List)

      28 to 48 kPa

      (EGR valve is fully closed)

      		 MAP value is at least +10 to 15 kPa higher than when EGR valve is fully closed

      80 to 110 kPa

      (After engine stall)

      Tech Tips

      During Active Test, if the idling condition does not change in response to EGR step position, then there is probably a malfunction in EGR valve.

      EGR Valve is Sticking in Close Side
      - EGR Step Position (Active Test)
      0 Steps 30 Steps or Higher
      Idling condition Steady idling Steady idling
      EGR Valve is Sticking in Open Side
      - EGR Step Position (Active Test)
      0 Steps 30 Steps or Higher
      Idling condition

      Rough idling or engine stall

      (Engine difficult to start)

      Rough idling or engine stall

      (Engine difficult to start)

    B

    CHECK HARNESS AND CONNECTOR (EGR VALVE ASSEMBLY - ECM - NO. 1 INTEGRATION RELAY) Click here

    A

  3. READ VALUE USING INTELLIGENT TESTER (MAP)


    1. Connect the intelligent tester to the DLC3.

    2. Start the engine.

    3. Turn the tester on.

    4. Warm up the engine.

    5. Enter the following menus: Powertrain / Engine and ECT / Data List / MAP.

    6. Read the MAP value at racing the engine.

      Standard
      Condition Specified Condition
      Ignition switch ON 80 to 110 kPa
      racing the engine Changes in response to accelerator pedal operation

    NG

    INSPECT VACUUM HOSE Click here

    OK

  4. CHECK FOR DEPOSIT (EXHAUST MANIFOLD CONVERTOR TO EGR VALVE ASSEMBLY)


    1. Check for cracks, damage, and clogs in the pipes between the exhaust manifold converter and the EGR valve assembly.

    2. Check for exhaust leaks at each connection point.

      Tech Tips

      This check may require the removal of components.

      OK
      No deposit

    NG

    REPAIR OR REPLACE MALFUNCTIONING PARTS

    OK

  5. CHECK FOR DEPOSIT (EGR VALVE ASSEMBLY TO INTAKE PORT)


    1. Check for cracks, damage, and clogs in the pipes between the intake port and the EGR valve assembly.

    2. Check for exhaust leaks at each connection point.

      Tech Tips

      This check may require the removal of components.

      OK
      No deposit

    NG

    REPAIR OR REPLACE MALFUNCTIONING PARTS

    OK

  6. REPLACE EGR VALVE ASSEMBLY


    1. Replace the EGR valve assembly Click here.


    NEXT

  7. CHECK WHETHER DTC OUTPUT RECURS (DTC P0400)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the tester on.

    4. Clear DTC Click here.

    5. Turn the ignition switch off and wait for 30 seconds.

    6. Turn the ignition switch to ON.

    7. Turn the tester on.

    8. Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher.

      Tech Tips

      The A/C switch and all accessory switches should be off.

    9. Drive the vehicle at 60 to 80 km/h (37 mph to 50 mph) with the shift lever in the 3rd position.

      CAUTION:

      When performing the confirmation driving pattern, obey all speed limits and traffic laws.

    10. Perform fuel-cut operation for 7 seconds or more, with the accelerator pedal fully released and the brake pedal pressed.

      Tech Tips


      • If the vehicle speed became lower than 40 km/h (25 mph) within 7 seconds, perform the confirmation driving pattern again.

    11. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

    12. Input the DTC: P0400.

    13. Check the DTC judgment result.

      Result
      Result Proceed to
      ABNORMAL A
      NORMAL B
      Tester Display Description
      NORMAL

      • DTC judgment completed

      • System normal
      ABNORMAL

      • DTC judgment completed

      • System abnormal
      INCOMPLETE

      • DTC judgment not completed

      • You should perform driving pattern after confirming DTC enabling conditions
      N/A

      • Unable to perform DTC judgment

      • Number of DTCs which do not fulfill DTC preconditions has reached ECU's memory limit

      Tech Tips


      • If the DTC judgment result is INCOMPLETE or N/A, drive the vehicle again at 60 km/h to 80 km/h (37 mph to 50 mph) with the shift lever in the 3rd position, perform fuel-cut operation for 7 seconds or more with the accelerator pedal fully released and the brake pedal pressed, and check the DTC judgment result.


    A

    END

    B

    REPLACE ECM Click here

  8. INSPECT VACUUM HOSE


    1. Vacuum hose is connected correctly and is not damaged.

    2. If a hose is damaged do not repair by cutting, and replace with a new part.


    OK

    REPLACE MANIFOLD ABSOLUTE PRESSURE SENSOR Click here

    NG

    REPLACE VACUUM HOSE

  9. CHECK HARNESS AND CONNECTOR (EGR VALVE ASSEMBLY - ECM - NO. 1 INTEGRATION RELAY)


    1. Disconnect the EGR valve assembly connector.

    2. Disconnect the ECM connector.

    3. Remove the No. 1 integration relay from engine room relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      B56-4 (EGR1) - B87-42 (EGR1) Always Below 1 Ω
      B56-3 (EGR2) - B87-64 (EGR2) Always Below 1 Ω
      B56-6 (EGR3) - B87-63 (EGR3) Always Below 1 Ω
      B56-1 (EGR4) - B87-43 (EGR4) Always Below 1 Ω
      1E-4 - B56-2 (+B1) Always Below 1 Ω
      1E-4 - B56-5 (+B2) Always Below 1 Ω
      B56-4 (EGR1) or B87-42 (EGR1) - Body ground Always 10 kΩ or higher
      B56-3 (EGR2) or B87-64 (EGR2) - Body ground Always 10 kΩ or higher
      B56-6 (EGR3) or B87-63 (EGR3) - Body ground Always 10 kΩ or higher
      B56-1 (EGR4) or B87-43 (EGR4) - Body ground Always 10 kΩ or higher
      B56-2 (+B1) or B56-5 (+B2) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  10. CHECK WHETHER DTC OUTPUT RECURS (DTC P0400)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the tester on.

    4. Clear DTC Click here.

    5. Turn the ignition switch off and wait for 30 seconds.

    6. Turn the ignition switch to ON.

    7. Turn the tester on.

    8. Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher.

      Tech Tips

      The A/C switch and all accessory switches should be off.

    9. Drive the vehicle at 60 to 80 km/h (37 mph to 50 mph) with the shift lever in the 3rd position.

      CAUTION:

      When performing the confirmation driving pattern, obey all speed limits and traffic laws.

    10. Perform fuel-cut operation for 7 seconds or more, with the accelerator pedal fully released and the brake pedal pressed.

      Tech Tips


      • If the vehicle speed became lower than 40 km/h (25 mph) within 7 seconds, perform the confirmation driving pattern again.

    11. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

    12. Input the DTC: P0400.

    13. Check the DTC judgment result.

      Result
      Result Proceed to
      ABNORMAL A
      NORMAL B
      Tester Display Description
      NORMAL

      • DTC judgment completed

      • System normal
      ABNORMAL

      • DTC judgment completed

      • System abnormal
      INCOMPLETE

      • DTC judgment not completed

      • You should perform driving pattern after confirming DTC enabling conditions
      N/A

      • Unable to perform DTC judgment

      • Number of DTCs which do not fulfill DTC preconditions has reached ECU's memory limit

      Tech Tips


      • If the DTC judgment result is INCOMPLETE or N/A, drive the vehicle again at 60 km/h to 80 km/h (37 mph to 50 mph) with the shift lever in the 3rd position, perform fuel-cut operation for 7 seconds or more with the accelerator pedal fully released and the brake pedal pressed, and check the DTC judgment result.


    B

    END

    A

  11. REPLACE EGR VALVE ASSEMBLY


    1. Replace the EGR valve assembly Click here.


    NEXT

  12. CHECK WHETHER DTC OUTPUT RECURS (DTC P0400)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the tester on.

    4. Clear DTC Click here.

    5. Turn the ignition switch off and wait for 30 seconds.

    6. Turn the ignition switch to ON.

    7. Turn the tester on.

    8. Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher.

      Tech Tips

      The A/C switch and all accessory switches should be off.

    9. Drive the vehicle at 60 to 80 km/h (37 mph to 50 mph) with the shift lever in the 3rd position.

      CAUTION:

      When performing the confirmation driving pattern, obey all speed limits and traffic laws.

    10. Perform fuel-cut operation for 7 seconds or more, with the accelerator pedal fully released and the brake pedal pressed.

      Tech Tips


      • If the vehicle speed became lower than 40 km/h (25 mph) within 7 seconds, perform the confirmation driving pattern again.

    11. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

    12. Input the DTC: P0400.

    13. Check the DTC judgment result.

      Result
      Result Proceed to
      ABNORMAL A
      NORMAL B
      Tester Display Description
      NORMAL

      • DTC judgment completed

      • System normal
      ABNORMAL

      • DTC judgment completed

      • System abnormal
      INCOMPLETE

      • DTC judgment not completed

      • You should perform driving pattern after confirming DTC enabling conditions
      N/A

      • Unable to perform DTC judgment

      • Number of DTCs which do not fulfill DTC preconditions has reached ECU's memory limit

      Tech Tips


      • If the DTC judgment result is INCOMPLETE or N/A, drive the vehicle again at 60 km/h to 80 km/h (37 mph to 50 mph) with the shift lever in the 3rd position, perform fuel-cut operation for 7 seconds or more with the accelerator pedal fully released and the brake pedal pressed, and check the DTC judgment result.


    A

    REPLACE ECM Click here

    B

    END