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Home >> Lexus >> 2015 >> GS 350 F Sport, AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Diagnostic Codes (2 Of 4) >> SFI System >> DTC P050A: Cold Start Idle Air Control System Performance [09/2014 - 10/2015] >> Procedure
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DTC P050A: Cold Start Idle Air Control System Performance [09/2014 - 10/2015]: 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 the menus: Powertrain / Engine and ECT / 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 [09/2014 - 10/2015] )

    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.

    1. Connect the Techstream to the DLC3.
    2. Start the engine.
    3. Turn the Techstream on.
    4. Enter the following menus: Powertrain / Engine and ECT / Data List / Short FT #1, Long FT #1, Short FT #2 and Long FT #2.
    5. Read the values displayed on the Techstream at engine idles.
    6. Add together the Short FT #1 and Long FT #1 values, and the Short FT #2 and Long FT #2 values to obtain the total fuel trim.

      OK

      The total of the Short FT #1 and Long FT #1 values, and the total of the Short FT #2 and Long FT #2 values is between -20% and 20%.

    Result: 

    NG 

    See step  5

    Result: 

    OK 

    See step  3

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

      OK

      No deposits around throttle valve and throttle valve moves smoothly.

      RESULT

      Result Proceed to
      NG A
      OK B

    Result: 

    B 

    See step  15

    Result: 

    A 

    See step  4

  4. REPAIR OR REPLACE THROTTLE BODY ASSEMBLY 
    1. Repair or replace the throttle body assembly (Refer to REMOVAL [09/2014 - 10/2015] ).

      HINT: 

      Perform "Inspection After Repair" after replacing the throttle body assembly (Refer to INITIALIZATION [09/2014 - 10/2015] ).

    Result: 

    NEXT 

    See step  14

  5. CHECK PCV SYSTEM 
    1. Check the PCV hose connections (Refer to PROCEDURE - Step 2 ).

      OK

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

    Result: 

    NG 

    See step  10

    Result: 

    OK 

    See step  6

  6. CHECK INTAKE SYSTEM 
    1. Check the intake system for vacuum leaks (Refer to PROCEDURE - Step 1 ).

      OK

      No leaks in intake system.

    Result: 

    NG 

    See step  11

    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

      Air cleaner filter element is not excessively contaminated with dirt or oil.

    Result: 

    NG 

    See step  12

    Result: 

    OK 

    See step  8

  8. PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE VVT LINEAR (BANK 1 OR BANK 2)) 
    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 DTC P0011 Inspection Procedure (VVT system for intake camshaft) (Refer to PROCEDURE - Step 2 ).
      2. Perform the Active Test, referring to DTC P0014 Inspection Procedure (VVT system for exhaust camshaft) (Refer to PROCEDURE - Step 2 ).

    Result: 

    NG 

    See step  13

    Result: 

    OK 

    See step  9

  9. READ VALUE USING TECHSTREAM (MAF) 
    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 and ECT / Data List / MAF, Coolant Temp and Engine Speed.
    5. Allow the engine to idle until Coolant Temp reaches 75°C (167°F) or higher.
    6. Read MAF with the engine speed at 3000 rpm.

      Standard

      Between 13.0 gm/sec and 14.0 gm/sec (shift lever: N, A/C: Off).

    Result: 

    OK 

    See step  15

    Result: 

    NG 

    See step  16

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

    Result: 

    NEXT 

    See step  14

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

      HINT: 

      Perform "Inspection After Repair" after replacing the intake system (Refer to INITIALIZATION [09/2014 - 10/2015] ).

    Result: 

    NEXT 

    See step  14

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

    Result: 

    NEXT 

    See step  14

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

      HINT: 

    Result: 

    NEXT 

    See step  14

  14. 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. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Clear the DTCs (Refer to DTC CHECK / CLEAR [09/2014 - 10/2015] ).
    5. Turn the engine switch off and wait for at least 30 seconds.
    6. Turn the engine switch on (IG) and turn the Techstream on.
    7. Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.
    8. Check that the engine coolant temperature is between -10 and 60°C (14 and 140°F).
    9. 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.
    10. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
    11. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
    12. Input the DTC: P050A.
    13. Check the DTC judgment result.

      Result

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

    Result: 

    A 

    END 

    Result: 

    B 

    See step  16

  15. 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. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Clear the DTCs (Refer to DTC CHECK / CLEAR [09/2014 - 10/2015] ).
    5. Turn the engine switch off and wait for at least 30 seconds.
    6. Turn the engine switch on (IG) and turn the Techstream on.
    7. Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.
    8. Check that the engine coolant temperature is between -10 and 60°C (14 and 140°F).
    9. 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.
    10. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
    11. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
    12. Input the DTC: P050A.
    13. Check the DTC judgment result.

      Result

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

    Result: 

    A 

    CHECK FOR INTERMITTENT PROBLEMS 

    (Refer to CHECK FOR INTERMITTENT PROBLEMS [09/2014 - 10/2015] )

    Result: 

    B 

    See step  16

  16. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER CONNECTOR CONNECTION) 
    1. Check the connection and terminal contact pressure of connectors and wire harnesses between the mass air flow meter and ECM (Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE [09/2014 - ] ).

      HINT: 

      Repair any problems.

    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. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Clear the DTCs (Refer to DTC CHECK / CLEAR [09/2014 - 10/2015] ).
    5. Turn the engine switch off and wait for at least 30 seconds.
    6. Turn the engine switch on (IG) and turn the Techstream on.
    7. Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.
    8. Check that the engine coolant temperature is between -10 and 60°C (14 and 140°F).
    9. 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.
    10. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
    11. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
    12. Input the DTC: P050A.
    13. Check the DTC judgment result.

      Result

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

    Result: 

    B 

    END 

    Result: 

    A 

    See step  18

  18. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM) 

    Refer to PROCEDURE - Step 3

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  19

  19. REPLACE MASS AIR FLOW METER 
    1. Replace the mass air flow meter (Refer to REMOVAL [09/2014 - 10/2015] ).

      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.
      • Perform "Inspection After Repair" after replacing the mass air flow meter (Refer to INITIALIZATION [09/2014 - 10/2015] ).

    Result: 

    NEXT 

    See step  20

  20. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED 
    NOTE:

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

    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Clear the DTCs (Refer to DTC CHECK / CLEAR [09/2014 - 10/2015] ).
    5. Turn the engine switch off and wait for at least 30 seconds.
    6. Turn the engine switch on (IG) and turn the Techstream on.
    7. Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.
    8. Check that the engine coolant temperature is between -10 and 60°C (14 and 140°F).
    9. 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.
    10. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
    11. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
    12. Input the DTC: P050A.
    13. Check the DTC judgment result.

      Result

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

    Result: 

    A 

    END 

    Result: 

    B 

    REPLACE ECM 

    (Refer to REMOVAL [09/2014 - 10/2015] )

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