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Home >> Lexus >> 2021 >> RX 450h Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (Diagnostic Codes) (4 Of 8) >> SFI System >> DTC P0400: Exhaust Gas Recirculation Flow; DTC P0401: Exhaust Gas Recirculation Flow Insufficient Detected; DTC P0402: Exhaust Gas Recirculation Flow Excessive Detected [07/2020 - ] >> Procedure
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DTC P0400: Exhaust Gas Recirculation Flow; DTC P0401: Exhaust Gas Recirculation Flow Insufficient Detected; DTC P0402: Exhaust Gas Recirculation Flow Excessive Detected [07/2020 - ]: Procedure

  1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0400, P0401, P0402) 
    1. Connect the Techstream to the DLC3.
    2. Turn the power switch on (IG).
    3. Turn the Techstream on.
    4. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
    5. Read the DTCs.

      Powertrain > Engine and ECT > Trouble Codes 

      Result

      Result Proceed to
      DTC P0400, P0401 or P0402 is output A
      DTC P0400, P0401 or P0402 and other DTCs are output B

      HINT: 

      If any DTCs other than P0400, P0401 or P0402 are output, troubleshoot those DTCs first.

    Result: 

    B 

    GO TO DTC CHART. Refer to  DIAGNOSTIC TROUBLE CODE CHART [07/2020 - ] 

    Result: 

    A 

    See step  2

  2. READ VALUE USING TECHSTREAM (MAP) 
    1. Connect the Techstream to the DLC3.
    2. Turn the power switch on (IG).
    3. Turn the Techstream on.
    4. Enter the following menus: Powertrain / Engine and ECT / Data List / MAP.

      Powertrain > Engine and ECT > Data List 

      Tester Display
      MAP
    5. Read the value of MAP.

      Standard

      Techstream Display Specified Condition
      MAP 80 to 110 kPa (11.6 to 15.95 psi)

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE MANIFOLD ABSOLUTE PRESSURE SENSOR. Refer to  REMOVAL [10/2015 - ] 

    Result: 

    OK 

    See step  3

  3. PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE EGR STEP POSITION) 
    1. Connect the Techstream to the DLC3.
    2. Turn the power switch on (IG).
    3. Turn the Techstream on.
    4. Put the engine in Inspection Mode (Maintenance Mode).

      Powertrain > Hybrid Control > Utility 

      Tester Display
      Inspection Mode
    5. Start the engine and warm it up until the engine coolant temperature is 75°C (167°F) or higher.

      HINT: 

      The A/C switch and all accessories should be off.

    6. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the EGR Step Position / Data List / MAP, Coolant Temp and Engine Independent.

      Powertrain > Engine and ECT > Active Test 

      Active Test Display
      Control the EGR Step Position
      Data List Display
      MAP
      Coolant Temp
      Engine Independent
    7. According to the display on the Techstream, compare the values of Data List item MAP before and while performing the Active Test.
      NOTE:
      • Make sure that the value of Data List item Engine Independent is "Operate" while performing the Active Test.
      • 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.
      • Do not open the EGR valve 30 steps or more during the Active Test.

      Standard

      The value of MAP changes according to the EGR valve step set by the Active Test.

      Data List Control the EGR Step Position (Active Test)
      Before Active Test
      (Engine idling)      		 0 Steps 0 to 30 Steps
      (Engine idling)
      MAP 20 to 40 kPa (2.9 to 5.8 psi) (EGR valve is fully closed) MAP value is at least +10 kPa (1.45 psi) higher than when EGR valve is fully closed

      HINT: 

      • If the value of Data List item Engine Independent is "Not Opr" when the engine is idling, charge control is being performed. Perform the Active Test after charge control is complete ("Operate" is displayed).
      • While performing the Active Test, if the increase in the value of MAP is small, the EGR valve assembly may be malfunctioning.
      • Even if the EGR valve assembly is malfunctioning, rough idling or an increase in the value of MAP may occur while performing the Active Test. However, the amount that the value of MAP increases will be smaller than normal.

      Result

      Result Proceed to
      Before performing the Active Test (while the engine is idling), the value of MAP is not between 20 to 40 kPa (2.9 to 5.8 psi). A
      When performing the Active Test to change the EGR valve step between 0 (EGR valve fully closed) and 30, the value of MAP changes less than 10 kPa (1.45 psi). B
      Other than above C

    Result: 

    B 

    See step  6

    Result: 

    C 

    See step  12

    Result: 

    A 

    See step  4

  4. CHECK INTAKE SYSTEM 
    1. Check the intake system for vacuum leaks.

      Refer to PROCEDURE - Step 1

      OK

      No leaks from intake system.

      HINT: 

      Perform "Inspection After Repair" after repairing or replacing the intake system.

      Refer to INITIALIZATION [10/2015 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE INTAKE SYSTEM 

    Result: 

    OK 

    See step  5

  5. INSPECT EGR VALVE ASSEMBLY 
    1. Remove the EGR valve assembly.

      Refer to REMOVAL [10/2015 - ]

    2. Check if the EGR valve is stuck open.

      OK

      EGR valve is tightly closed.

      HINT: 

      Perform "Inspection After Repair" after replacing the EGR valve assembly.

      Refer to INITIALIZATION [10/2015 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE MANIFOLD ABSOLUTE PRESSURE SENSOR. Refer to  REMOVAL [10/2015 - ] 

    Result: 

    NG 

    REPLACE EGR VALVE ASSEMBLY. Refer to  REMOVAL [10/2015 - ] 

  6. REPLACE EGR VALVE ASSEMBLY 
    1. Replace the EGR valve assembly.

      Refer to REMOVAL [10/2015 - ]

      HINT: 

      Perform "Inspection After Repair" after replacing the EGR valve assembly.

      Refer to INITIALIZATION [10/2015 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  7

  7. CLEAR DTC 
    1. Connect the Techstream to the DLC3.
    2. Turn the power switch on (IG).
    3. Turn the Techstream on.
    4. Clear the DTCs.

      Powertrain > Engine and ECT > Clear DTCs 

    5. Turn the power switch off and wait for at least 30 seconds.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  8

  8. CHECK WHETHER DTC OUTPUT RECURS (DTC P0400, P0401 OR P0402) 
    1. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
    2. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

      Powertrain > Engine and ECT > Utility 

      Tester Display
      All Readiness
    3. Input the DTC: P0400, P0401 or P0402.
    4. Check the DTC judgment result.

      Result

      Result Proceed to
      NORMAL
      (DTCs are not output)      		 A
      ABNORMAL
      (DTC P0400, P0401 or P0402 is output)      		 B

    Result: 

    A 

    END 

    Result: 

    B 

    See step  9

  9. REPLACE EGR COOLER ASSEMBLY 
    1. Replace the EGR cooler assembly.

      Refer to REMOVAL [10/2015 - ]

      HINT: 

      • If any of the EGR system related pipes (EGR pipe, exhaust manifold, etc.) are cracked, damaged or clogged, replace them as necessary.
      • Perform "Inspection After Repair" after replacing the EGR system.

        Refer to INITIALIZATION [10/2015 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  10

  10. CLEAR DTC 
    1. Connect the Techstream to the DLC3.
    2. Turn the power switch on (IG).
    3. Turn the Techstream on.
    4. Clear the DTCs.

      Powertrain > Engine and ECT > Clear DTCs 

    5. Turn the power switch off and wait for at least 30 seconds.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  11

  11. CHECK WHETHER DTC OUTPUT RECURS (DTC P0400, P0401 OR P0402) 
    1. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
    2. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

      Powertrain > Engine and ECT > Utility 

      Tester Display
      All Readiness
    3. Input the DTC: P0400, P0401 or P0402.
    4. Check the DTC judgment result.

      Result

      Techstream Display Description
      NORMAL
      • DTC judgment completed
      • System normal
      ABNORMAL
      • DTC judgment completed
      • System abnormal
      INCOMPLETE
      • DTC judgment not completed
      • 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 memory limit

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    END 

  12. CLEAR DTC 
    1. Connect the Techstream to the DLC3.
    2. Turn the power switch on (IG).
    3. Turn the Techstream on.
    4. Clear the DTCs.

      Powertrain > Engine and ECT > Clear DTCs 

    5. Turn the power switch off and wait for at least 30 seconds.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  13

  13. CHECK WHETHER DTC OUTPUT RECURS (DTC P0400, P0401 OR P0402) 
    1. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
    2. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

      Powertrain > Engine and ECT > Utility 

      Tester Display
      All Readiness
    3. Input the DTC: P0400, P0401 or P0402.
    4. Check the DTC judgment result.

      Result

      Result Proceed to
      NORMAL
      (DTCs are not output)      		 A
      ABNORMAL
      (DTC P0400, P0401 or P0402 is output)      		 B

      HINT: 

      Perform "Inspection After Repair" after replacing the EGR valve assembly.

      Refer to INITIALIZATION [10/2015 - ]

    Result: 

    A 

    END 

    Result: 

    B 

    REPLACE EGR VALVE ASSEMBLY. Refer to  REMOVAL [10/2015 - ] 

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