СИСТЕМА ECD, Diagnostic DTC:P0400

DTC Code DTC Name
P0400 Exhaust Gas Recirculation Flow

DESCRIPTION

The EGR system recirculates exhaust gases. The recirculated gasses mix with the intake air so that 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 EGR valve angle and the throttle valve angle.

DTC No. Detection Item DTC Detection Condition Trouble Area MIL Memory
P0400 Exhaust Gas Recirculation Flow Mass air flow rate is not changed when turning on the electric EGR control valve assembly while decelerating (2 trip detection logic).

  • EGR valve deposit

  • EGR valve passage deposit

  • EGR pipe with cooler sub-assembly

  • Mass air flow meter assembly

 Comes on DTC stored
Table 1. Related Data List
DTC No. Data List
P0400

  • MAF

  • Target EGR Position

  • Actual EGR Valve Pos.

MONITOR DESCRIPTION

If the electric EGR control valve assembly is forcibly operated during deceleration but the intake air amount does not vary, the ECM determines that the electric EGR control valve assembly is malfunctioning. The ECM then illuminates the MIL (2 trip detection logic).

A012HWRE08

CONFIRMATION DRIVING PATTERN

DTC No. DTC Detection Drive Pattern
P0400 After warming up the engine, decelerate from a speed of 80 km/h (50 mph) or more (fully release the accelerator pedal for approximately 5 seconds).

CAUTION / NOTICE / HINT

Note:

After replacing the ECM, the new ECM needs registration (Click here) and initialization (Click hereНажмите здесь).

Tip:

Read freeze frame data using the GTS. 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, and other data from the time the malfunction occurred.

PROCEDURE

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

    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON and turn the GTS on.

    3. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

    4. Read the DTCs.

      Powertrain > Engine and ECT > Trouble Codes
      Result
      ResultProceed to
      DTC P0400 is outputA
      DTC P0400 and other DTCs are outputB
      Tip:

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

    B

    GO TO DTC CHART Click here Нажмите здесь

    A

  2. PERFORM ACTIVE TEST USING GTS (ACTIVATE THE EGR VALVE CLOSE)

    1. Connect the GTS to the DLC3.

    2. Start the engine and warm it up, and make sure the A/C switch and all accessory switches are off.

    3. Turn the ignition switch off and for 30 seconds.

    4. Start the engine and turn the GTS on.

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

      Powertrain > Engine and ECT > Data List
      Tester Display
      MAF

    6. Read the MAF value displayed on the GTS while the engine is idling.

    7. Enter the following menus: Powertrain / Engine and ECT / Active Test / Activate the EGR Valve Close / All Data / MAF.

      Powertrain > Engine and ECT > Active Test
      Active Test Display
      Activate the EGR Valve Close
      Data List Display
      MAF

    8. Read the MAF value when the EGR valve is closed using the Active Test function.

      Tip:

      • If idling continues for 20 minutes or more, the EGR valve target opening angle becomes 0% (EGR valve fully closed). As this makes diagnosis impossible, it becomes necessary to drive the vehicle or to restart the engine.

      • Before performing diagnosis, confirm that the EGR valve target opening angle is not 0%.

      • When "Coolant Temp" is 75°C (167°F) or higher during idle, the exhaust gas flows through the EGR pipe with cooler sub-assembly. If MAF does not change when the EGR is cut even though the EGR valve is operating normally, the EGR pipe with cooler sub-assembly may be clogged.

      • When idling while warming up the engine, the actuator operates and the EGR pipe with cooler sub-assembly is bypassed. However, if the connector of the No. 1 vacuum switching valve assembly (for EGR cooler) is disconnected, the EGR pipe with cooler sub-assembly is not bypassed and it is possible to check if the EGR pipe with cooler sub-assembly is clogged.

      Result
      Active Test Result Proceed to

      Activate the EGR Valve Close:

      OFF (Open) to Close

      		 MAF value does not change A
      MAF value changes B
      Note:

      As the measured values may differ from those shown below due to factors such as differences in measuring environments and changes in vehicle condition due to aging, do not use these values to determine whether the vehicle is malfunctioning or not.

      Tip:

      The problem may be a temporary, due to the entry of deposits or foreign matter. Check that there are no deposits or foreign matter in the electric EGR control valve assembly or mass air flow meter assembly.

      Reference
      EGR Valve Condition (Opening) Measuring Condition MAF (Reference)
      Open (67%)

      • Atmosphere pressure: 101 kPa

      • Intake air temperature: 30°C (86°F)

      • Engine coolant temperature: 88°C (190°F)

      		 3 to 12 gm/sec
      Closed (0%) 7 gm/sec or more
    B Нажмите здесь

    A

  3. READ VALUE USING GTS (MAF)

    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON and turn the GTS on.

    3. Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / MAF.

      Powertrain > Engine and ECT > Data List
      Tester Display
      MAF
      Standard
      GTS DisplayConditionStandard
      MAFIgnition switch ON (do not start engine)0.35 gm/sec or less
      Result
      Proceed to
      OK
      NG
    NG Нажмите здесь

    OK

  4. PERFORM ACTIVE TEST USING GTS (ACTIVATE THE VSV FOR EGR COOLER BYPASS)

    1. Connect the GTS to the DLC3.

    2. Start the engine and warm it up, and make sure the A/C switch and all accessory switches are off.

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

    4. Start the engine and turn the GTS on.

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

      Powertrain > Engine and ECT > Data List
      Tester Display
      MAF

    6. Read the MAF value displayed on the GTS while the engine is idling.

    7. Enter the following menus: Powertrain / Engine and ECT / Active Test / Activate the VSV for EGR Cooler Bypass / Data List / All Data / EGR Cooler Bypass Position and MAF.

      Powertrain > Engine and ECT > Active Test
      Active Test Display
      Activate the VSV for EGR Cooler Bypass
      Data List Display
      MAF
      EGR Cooler Bypass Position
      Tip:

      Whether the EGR is passing through the bypass side or cooler side during the Active Test can be confirmed by checking EGR Cooler Bypass Position.

    8. Using the Active Test function, switch the No. 1 vacuum switching valve assembly (for EGR cooler) between "Cooler" and "Bypass" a few times, and then check whether the MAF value changes after switching the valve from "Cooler" to "Bypass".

      Tip:

      If idling continues for 20 minutes or more, the EGR valve target opening angle becomes 0% (EGR valve fully closed). As this makes diagnosis impossible, it becomes necessary to drive the vehicle or restart the engine.

      Result
      GTS Display Result Proceed to

      Activate the VSV for EGR Cooler Bypass:

      Cooler to Bypass

      		 MAF value does not change A
      MAF value changes B
      Tip:

      If the EGR pipe with cooler sub-assembly is clogged, the MAF value changes.

    B Нажмите здесь

    GO TO STEP 6

    A

  5. CHECK FOR DEPOSIT (ELECTRIC EGR CONTROL VALVE ASSEMBLY)

    1. Remove the electric EGR control valve assembly.

      Click hereНажмите здесь

    2. Visually check the electric EGR control valve assembly for deposits. If there are deposits, clean the electric EGR control valve assembly.

      Note:

      • When cleaning the electric EGR control valve assembly, make sure the valve is completely closed.

      • When cleaning the electric EGR control valve assembly, perform initialization procedure.

        Click hereНажмите здесь

      • Do not forcibly open the valve, as it may be damaged or deformed.

      • When cleaning the electric EGR control valve assembly, use a piece of cloth soaked with cleaning solvent. Spraying solvent directly onto these parts or soaking the parts in solvent may damage the parts.

      • When cleaning the electric EGR control valve assembly, care should be taken to prevent the ingress of cleaning solvent into the bearings of valve shaft, and when wiping off deposits on the electric EGR control valve assembly, care should be taken not to push the deposits into the bearings of valve shaft. These contaminants may adversely affect on the function of electric EGR control valve assembly.

      Tip:

      • If the EGR valve does not open properly or is stuck closed, the amount of intake air increases and combustion sounds and engine vibration may increase.

      • If the EGR valve does not close properly or is stuck open, the amount of recirculated exhaust gas becomes excessive and combustion becomes unstable. Also, there may be a lack of power.

      Result
      Proceed to
      NEXT
    NEXT

  6. REPLACE EGR PIPE WITH COOLER SUB-ASSEMBLY

    1. Replace the EGR pipe with cooler sub-assembly.

      Click hereНажмите здесь

      Result
      Proceed to
      NEXT
    NEXT

  7. CHECK WHETHER DTC OUTPUT RECURS (DTC P0400)

    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON and turn the GTS on.

    3. Clear the DTCs.

      Powertrain > Engine and ECT > Clear DTCs

    4. Turn the ignition switch off for 30 seconds or more.

    5. Start the engine and warm it up.

    6. Move the shift lever to 2nd gear and decelerate from a speed of 50 km/h (31 mph) or more (fully release the accelerator for approximately 5 seconds or more).

      ОСТОРОЖНО

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

    7. Turn the GTS on.

    8. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

    9. Read the DTCs.

      Powertrain > Engine and ECT > Trouble Codes
      Tip:

      When a DTC is output, the mass air flow meter assembly may be malfunctioning.

      Result
      Proceed to
      NEXT
    NEXT

    END

  8. REPLACE MASS AIR FLOW METER ASSEMBLY

    1. Replace the mass air flow meter assembly.

      Click hereНажмите здесь

      Tip:

      If foreign matter is stuck inside the mass air flow meter assembly, the output characteristics of the mass air flow meter assembly may change, resulting in a malfunction.

      Result
      Proceed to
      NEXT
    NEXT Нажмите здесь

    GO TO STEP 7

  9. PERFORM ACTIVE TEST USING GTS (ACTIVATE THE VSV FOR EGR COOLER BYPASS)

    1. Connect the GTS to the DLC3.

    2. Start the engine and warm it up, and make sure the A/C switch and all accessory switches are off.

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

    4. Start the engine and turn the GTS on.

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

      Powertrain > Engine and ECT > Data List
      Tester Display
      MAF

    6. Read the MAF value displayed on the GTS while the engine is idling.

    7. Enter the following menus: Powertrain / Engine and ECT / Active Test / Activate the VSV for EGR Cooler Bypass / Data List / All Data / EGR Cooler Bypass Position and MAF.

      Tip:

      Whether the EGR is passing through the bypass side or cooler side during the Active Test can be confirmed by checking EGR Cooler Bypass Position.

      Powertrain > Engine and ECT > Active Test
      Active Test Display
      Activate the VSV for EGR Cooler Bypass
      Data List Display
      MAF
      EGR Cooler Bypass Position

    8. Using the Active Test function, switch the No. 1 vacuum switching valve assembly (for EGR cooler) between "Cooler" and "Bypass" a few times, and then check whether the MAF value changes after switching the valve from "Cooler" to "Bypass".

      Tip:

      If idling continues for 20 minutes or more, the EGR valve target opening angle becomes 0% (EGR valve fully closed). As this makes diagnosis impossible, it becomes necessary to drive the vehicle or restart the engine.

      Result
      GTS Display Result Proceed to

      Activate the VSV for EGR Cooler Bypass:

      Cooler to Bypass

      		 MAF value does not change A
      MAF value changes B
      Tip:

      If the EGR pipe with cooler sub-assembly is clogged, the MAF value changes.

    B Нажмите здесь

    GO TO STEP 6

    A

  10. CHECK WHETHER DTC OUTPUT RECURS (DTC P0400)

    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON and turn the GTS on.

    3. Clear the DTCs.

      Powertrain > Engine and ECT > Clear DTCs

    4. Turn the ignition switch off for 30 seconds or more.

    5. Start the engine and warm it up.

    6. Move the shift lever to 2nd gear and decelerate from a speed of 50 km/h (31 mph) or more (fully release the accelerator for approximately 5 seconds or more).

      ОСТОРОЖНО

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

    7. Turn the GTS on.

    8. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

    9. Read the DTCs.

      Powertrain > Engine and ECT > Trouble Codes
      Tip:

      When a DTC is output, the mass air flow meter assembly may be malfunctioning.

      Result
      Proceed to
      NEXT
    NEXT

    END