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Home >> Lexus >> 2021 >> LC 500 2D Convertible >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Diagnostic Codes (Convertible) (5 Of 7) >> SFI System >> DTC P050A: Cold Start Idle Air Control System Performance [07/2020 - ] >> Procedure

DTC P050A: Cold Start Idle Air Control System Performance [07/2020 - ]: Procedure

  1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P050A) 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Enter the following menus: Powertrain / Engine / Trouble Codes.

      Powertrain > Engine > Trouble Codes 

    5. Read the DTCs.

      Result

      Result Proceed to
      DTC P050A is output A
      DTC P050A and other DTCs are output B

      HINT: 

      If any DTCs other than P050A are output, troubleshoot those DTCs first.

    Result: 

    B 

    GO TO DTC CHART. Refer to  DIAGNOSTIC TROUBLE CODE CHART [07/2020 - 05/2023]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [05/2023 - ] 

    Result: 

    A 

    See step  2

  2. READ VALUE USING TECHSTREAM (FUEL TRIM) 

    HINT: 

    Calculate the total fuel trim values to check the characteristic deviation of the mass air flow meter sub-assembly.

    1. Connect the Techstream to the DLC3.
    2. Start the engine.
    3. Turn the Techstream on.
    4. Enter the following menus: Powertrain / Engine / Data List / Gas AF Control / Short FT B1S1, Long FT B1S1, Short FT B2S1 and Long FT B2S1.

      Powertrain > Engine > Data List 

      Tester Display
      Short FT B1S1
      Long FT B1S1
      Short FT B2S1
      Long FT B2S1
    5. Read the values displayed on the Techstream at engine idle.
    6. Add together the Short FT B1S1 and Long FT B1S1 values, and the Short FT B2S1 and Long FT B2S1 values to obtain the total fuel trim.

      Standard

      The total of the Short FT B1S1 and Long FT B1S1 values, and the total of the Short FT B2S1 and Long FT B2S1 values is between -20% and 20%.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  5

    Result: 

    OK 

    See step  3

  3. INSPECT THROTTLE BODY WITH MOTOR ASSEMBLY (THROTTLE VALVE) 
    1. Inspect that there are no deposits around the throttle valve and throttle valve condition.

      OK

      No deposits around the throttle valve and throttle valve moves smoothly.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    See step  11

    Result: 

    NG 

    See step  4

  4. REPAIR OR REPLACE THROTTLE BODY WITH MOTOR ASSEMBLY 
    1. Repair or replace the throttle body with motor assembly.

      Refer to REMOVAL [07/2020 - ]

      HINT: 

      Perform "Inspection After Repair" after replacing the throttle body with motor assembly.

      Refer to INITIALIZATION [07/2020 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  16

  5. CHECK PCV SYSTEM 
    1. Check the PCV hose connections.

      Refer to COMPONENTS [07/2020 - ]

      OK

      PCV valve and hose are connected correctly and are not damaged.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  15

    Result: 

    OK 

    See step  6

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

      Refer to ON-VEHICLE INSPECTION [07/2020 - ]

      OK

      No leaks from intake system.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  14

    Result: 

    OK 

    See step  7

  7. CHECK AIR CLEANER FILTER ELEMENT SUB-ASSEMBLY 
    1. Visually check that the air cleaner filter element sub-assembly is not excessively contaminated with dirt or oil.

      OK

      The air cleaner filter element sub-assembly is not excessively contaminated with dirt or oil.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  13

    Result: 

    OK 

    See step  8

  8. PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE VVT-IE LINEAR AND CONTROL THE VVT EXHAUST LINEAR) 
    1. Operate the VVT system through the Active Test, and check if the VVT system is operating normally.
      1. Perform the Active Test, referring to ON-VEHICLE INSPECTION of camshaft timing control motor with EDU assembly (VVT-iE system for intake camshaft).

        Refer to ON-VEHICLE INSPECTION [07/2020 - ]

      2. Perform the Active Test, referring to DTC P0014 Procedure (VVT system for exhaust camshaft).

        Refer to PROCEDURE - Step 2

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  12

    Result: 

    OK 

    See step  9

  9. READ VALUE USING TECHSTREAM (MAF SENSOR) 

    Refer to PROCEDURE - Step 14 [07/2020 - 05/2023] , or refer to PROCEDURE - Step 14 [05/2023 - ]

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    See step  18

    Result: 

    OK 

    See step  10

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

      Powertrain > Engine > Clear DTCs 

    5. Turn the engine 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 P050A) 
    NOTE:

    In this operation, the engine must be cold (approximately the same as the engine coolant temperature recorded in the freeze frame data).

    1. Turn the engine switch on (IG).
    2. Turn the Techstream on.
    3. Enter the following menus: Powertrain / Engine / Data List / Primary / Coolant Temp.

      Powertrain > Engine > Data List 

      Tester Display
      Coolant Temp
    4. Check that the engine coolant temperature is between -10 and 60°C (14 and 140°F).
    5. Start the engine and warm it up until the engine coolant temperature is the same as the engine coolant temperature in the freeze frame data.
    6. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
    7. Enter the following menus: Powertrain / Engine / Utility / All Readiness.

      Powertrain > Engine > Utility 

      Tester Display
      All Readiness
    8. Input the DTC: P050A.
    9. Check the DTC judgment result.

      Result

      Result Proceed to
      NORMAL (DTCs are not output) A
      ABNORMAL (DTC P050A is output) B

    Result: 

    A 

    CHECK FOR INTERMITTENT PROBLEMS. Refer to  CHECK FOR INTERMITTENT PROBLEMS [07/2020 - ] 

    Result: 

    B 

    See step  18

  12. CHECK AND REPAIR VVT SYSTEM 
    1. Check and repair the VVT system.

      HINT: 

      • Refer to DTC P0011 Procedure (VVT-iE system for intake camshaft).

        Refer to PROCEDURE - Step 1

      • Refer to DTC P0014 Procedure (VVT system for exhaust camshaft).

        Refer to PROCEDURE - Step 1

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  16

  13. REPLACE AIR CLEANER FILTER ELEMENT SUB-ASSEMBLY 
    1. Replace the air cleaner filter element sub-assembly.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  16

  14. REPAIR OR REPLACE INTAKE SYSTEM 
    1. Repair or replace the intake system.

      HINT: 

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

      Refer to INITIALIZATION [07/2020 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  16

  15. REPAIR OR REPLACE PCV HOSE 
    1. Repair or replace PCV valve or hose.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  16

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

      Powertrain > Engine > Clear DTCs 

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

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  17

  17. CHECK WHETHER DTC OUTPUT RECURS (DTC P050A) 
    NOTE:

    In this operation, the engine must be cold (approximately the same as the engine coolant temperature recorded in the freeze frame data).

    1. Turn the engine switch on (IG).
    2. Turn the Techstream on.
    3. Enter the following menus: Powertrain / Engine / Data List / Primary / Coolant Temp.

      Powertrain > Engine > Data List 

      Tester Display
      Coolant Temp
    4. Check that the engine coolant temperature is between -10 and 60°C (14 and 140°F).
    5. Start the engine and warm it up until the engine coolant temperature is the same as the engine coolant temperature in the freeze frame data.
    6. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
    7. Enter the following menus: Powertrain / Engine / Utility / All Readiness.

      Powertrain > Engine > Utility 

      Tester Display
      All Readiness
    8. Input the DTC: P050A.
    9. Check the DTC judgment result.

      Result

      Result Proceed to
      NORMAL (DTCs are not output) A
      ABNORMAL (DTC P050A is output) B

    Result: 

    A 

    END 

    Result: 

    B 

    See step  18

  18. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY CONNECTOR CONNECTION) 
    1. Check the connection and terminal contact pressure of connectors and wire harnesses between the mass air flow meter sub-assembly and ECM.

      Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE [07/2020 - ]

      HINT: 

      Repair any problems.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  19

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

      Powertrain > Engine > Clear DTCs 

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

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  20

  20. CHECK WHETHER DTC OUTPUT RECURS (DTC P050A) 
    NOTE:

    In this operation, the engine must be cold (approximately the same as the engine coolant temperature recorded in the freeze frame data).

    1. Turn the engine switch on (IG).
    2. Turn the Techstream on.
    3. Enter the following menus: Powertrain / Engine / Data List / Primary / Coolant Temp.

      Powertrain > Engine > Data List 

      Tester Display
      Coolant Temp
    4. Check that the engine coolant temperature is between -10 and 60°C (14 and 140°F).
    5. Start the engine and warm it up until the engine coolant temperature is the same as the engine coolant temperature in the freeze frame data.
    6. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
    7. Enter the following menus: Powertrain / Engine / Utility / All Readiness.

      Powertrain > Engine > Utility 

      Tester Display
      All Readiness
    8. Input the DTC: P050A.
    9. Check the DTC judgment result.

      Result

      Result Proceed to
      ABNORMAL (DTC P050A is output) A
      NORMAL (DTCs are not output) B

    Result: 

    B 

    END 

    Result: 

    A 

    See step  21

  21. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM) 

    Refer to PROCEDURE - Step 2

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  22

  22. REPLACE MASS AIR FLOW METER SUB-ASSEMBLY 
    1. Replace the mass air flow meter sub-assembly.

      Refer to REMOVAL [07/2020 - ]

      HINT: 

      • If the result of the inspection performed in step 9 indicated no problem, proceed to the next step without replacing the mass air flow meter sub-assembly.
      • Perform "Inspection After Repair" after replacing the meter sub-assembly.

        Refer to INITIALIZATION [07/2020 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  23

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

      Powertrain > Engine > Clear DTCs 

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

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  24

  24. CHECK WHETHER DTC OUTPUT RECURS (DTC P050A) 
    NOTE:

    In this operation, the engine must be cold (approximately the same as the engine coolant temperature recorded in the freeze frame data).

    1. Turn the engine switch on (IG).
    2. Turn the Techstream on.
    3. Enter the following menus: Powertrain / Engine / Data List / Primary / Coolant Temp.

      Powertrain > Engine > Data List 

      Tester Display
      Coolant Temp
    4. Check that the engine coolant temperature is between -10 and 60°C (14 and 140°F).
    5. Start the engine and warm it up until the engine coolant temperature is the same as the engine coolant temperature in the freeze frame data.
    6. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
    7. Enter the following menus: Powertrain / Engine / Utility / All Readiness.

      Powertrain > Engine > Utility 

      Tester Display
      All Readiness
    8. Input the DTC: P050A.
    9. Check the DTC judgment result.

      Result

      Result Proceed to
      ABNORMAL (DTC P050A is output) A
      NORMAL (DTCs are not output) B

    Result: 

    A 

    END 

    Result: 

    B 

    REPLACE ECM. Refer to  REMOVAL [07/2020 - 05/2023]  , or refer to  REMOVAL [05/2023 - ] 

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