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Home >> Lexus >> 2017 >> GX 460 Luxury >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (Diagnostic Codes) (4 Of 7) >> SFI System >> DTC P050A: Cold Start Idle Air Control System Performance [08/2015 - 08/2018] >> Procedure
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DTC P050A: Cold Start Idle Air Control System Performance [08/2015 - 08/2018]: Procedure

  1. CHECK FOR ANY OTHER DTCS OUTPUT 
    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 [08/2015 - 08/2016] , or refer to DIAGNOSTIC TROUBLE CODE CHART [08/2016 - 08/2017] , or refer to DIAGNOSTIC TROUBLE CODE CHART [08/2017 - 08/2019] )

    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 and warm it up.
    3. Turn the Techstream on.
    4. Enter the following menus: Powertrain / Engine and ECT / Data List / Short FT #1 and Long FT #1, or Short FT #2 and Long FT #2.
    5. Read the values displayed on the Techstream.
    6. Add together the Short FT #1 and Long FT #1, or Short FT #2 and Long FT #2 values to obtain the total fuel trim.

      Result

      Total of Short FT #1 and Long FT #1, or Short FT #2 and Long FT #2 values is between -20% and 20%.

    Result: 

    NG 

    See step  7

    Result: 

    OK 

    See step  3

  3. INSPECT THROTTLE BODY ASSEMBLY 
    1. Check for deposits around the throttle valve and check the throttle valve condition.

      OK

      No deposits around throttle valve and throttle valve moves smoothly.

    Result: 

    NG 

    See step  6

    Result: 

    OK 

    See step  4

  4. PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE EGR STEP POSITION) 
    1. Connect the Techstream to the DLC3.
    2. Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher.

      HINT: 

      • When performing the Active Test, make sure the shift lever is in P or N.
      • The A/C switch and all accessory switches should be off.
    3. Turn the Techstream on.
    4. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the EGR Step Position.
    5. 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.

      HINT: 

      • 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)
      Step 0 Step 0 to 30
      Idling condition Steady idling Idling changes from steady to rough idling or engine stalls
      MAP
      (Data List)      		 20 to 40 kPa (150 to 300 mmHg) MAP value is at least 10 kPa (75 mmHg) higher than when EGR valve is fully closed

    Result: 

    OK 

    See step  19

    Result: 

    NG 

    See step  5

  5. INSPECT EGR VALVE ASSEMBLY 
    1. Remove the EGR valve assembly (Refer to REMOVAL [08/2015 - ] ).
    2. Check if the EGR valve is stuck open.

      OK

      EGR valve is tightly closed.

    Result: 

    OK 

    See step  19

    Result: 

    NG 

    See step  17

  6. REPAIR OR REPLACE THROTTLE BODY ASSEMBLY 
    1. Repair or replace the throttle body assembly (Refer to REMOVAL [08/2015 - ] ).

      HINT: 

      Perform "Inspection After Repair" after repairing or replacing the throttle body assembly (Refer to INITIALIZATION [08/2015 - ] ).

    Result: 

    NEXT 

    See step  19

  7. CHECK PCV SYSTEM 
    1. Check the PCV hose connections (Refer to PROCEDURE - Step 3 ).

      OK

      PCV hose is connected correctly and is not damaged.

    Result: 

    NG 

    See step  14

    Result: 

    OK 

    See step  8

  8. CHECK INTAKE SYSTEM 
    1. Check the intake system for vacuum leaks (Refer to PROCEDURE - Step 3 ).

      OK

      No leaks in intake system.

    Result: 

    NG 

    See step  15

    Result: 

    OK 

    See step  9

  9. INSPECT AIR CLEANER FILTER ELEMENT SUB-ASSEMBLY 
    1. Visually check that the air cleaner filter element 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  16

    Result: 

    OK 

    See step  10

  10. PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE EGR STEP POSITION) 
    1. Connect the Techstream to the DLC3.
    2. Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher.

      HINT: 

      • When performing the Active Test, make sure the shift lever is in P or N.
      • The A/C switch and all accessory switches should be off.
    3. Turn the Techstream on.
    4. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the EGR Step Position.
    5. 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.

      HINT: 

      • 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)
      Step 0 Step 0 to 30
      Idling condition Steady idling Idling changes from steady to rough idling or engine stalls
      MAP
      (Data List)      		 20 to 40 kPa (150 to 300 mmHg) MAP value is at least 10 kPa (75 mmHg) higher than when EGR valve is fully closed

    Result: 

    OK 

    See step  12

    Result: 

    NG 

    See step  11

  11. INSPECT EGR VALVE ASSEMBLY 
    1. Remove the EGR valve assembly (Refer to REMOVAL [08/2015 - ] ).
    2. Check if the EGR valve is stuck open.

      OK

      EGR valve is tightly closed.

    Result: 

    NG 

    See step  17

    Result: 

    OK 

    See step  12

  12. PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE VVT SYSTEM) 
    1. Connect the Techstream to the DLC3.
    2. Start the engine and turn the Techstream on.
    3. Warm up the engine.
    4. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the VVT System (Bank 1) or Control the VVT System (Bank 2).
    5. Check the engine speed while operating the camshaft timing oil control valve using the Techstream.

      OK

      Techstream Operation Engine Condition
      OFF Normal engine speed
      ON Engine idles roughly or stalls soon after camshaft timing oil control valve switched from off to on

    Result: 

    NG 

    See step  18

    Result: 

    OK 

    See step  13

  13. 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 and Coolant Temp.
    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 18.3 gm/sec. and 25.8 gm/sec. (shift lever: N; A/C: Off).

    Result: 

    OK 

    See step  19

    Result: 

    NG 

    See step  20

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

    Result: 

    NEXT 

    See step  19

  15. 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 [08/2015 - ] ).

    Result: 

    NEXT 

    See step  19

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

    Result: 

    NEXT 

    See step  19

  17. REPLACE EGR VALVE ASSEMBLY 
    1. Replace the EGR valve assembly (Refer to REMOVAL [08/2015 - ] ).

      HINT: 

      Perform "Inspection After Repairs" after replacing the EGR valve assembly (Refer to INITIALIZATION [08/2015 - ] ).

    Result: 

    NEXT 

    See step  19

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

      HINT: 

    Result: 

    NEXT 

    See step  19

  19. CHECK WHETHER DTC OUTPUT RECURS 
    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 [08/2015 - ] ).
    5. Turn the engine switch off.
    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°C and 50°C (14 and 122°F).
    9. Start the engine and warm it up.
    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 (No output) A
      ABNORMAL (P050A is output) B

    Result: 

    A 

    CHECK FOR INTERMITTENT PROBLEMS 

    (Refer to CHECK FOR INTERMITTENT PROBLEMS [08/2015 - ] )

    Result: 

    B 

    See step  20

  20. CHECK HARNESS AND CONNECTOR 
    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 [08/2015 - ] ).

      HINT: 

      Repair any problems.

    Result: 

    NEXT 

    See step  21

  21. CHECK WHETHER DTC OUTPUT RECURS 
    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 [08/2015 - ] ).
    5. Turn the engine switch off.
    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°C and 50°C (14 and 122°F).
    9. Start the engine and warm it up.
    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 (P050A is output) A
      NORMAL (No output) B

    Result: 

    B 

    END 

    Result: 

    A 

    See step  22

  22. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM) 
    1. Disconnect the mass air flow meter connector.
    2. Disconnect the ECM connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      C27-3 (VG) - C29-14 (VG) Always Below 1 Ω
      C27-2 (E2G) - C29-13 (E2G) Always Below 1 Ω
      C27-3 (VG) or C29-14 (VG) - Body ground Always 10 kΩ or higher

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  23

  23. REPLACE MASS AIR FLOW METER 
    1. Replace the mass air flow meter (Refer to REMOVAL [08/2015 - ] ).

      HINT: 

      • If the result of the inspection performed in step 13 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 [08/2015 - ] ).

    Result: 

    NEXT 

    See step  24

  24. 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 [08/2015 - ] ).
    5. Turn the engine switch off.
    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°C and 50°C (14 and 122°F).
    9. Start the engine and warm it up.
    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 (No output) A
      ABNORMAL (P050A is output) B

    Result: 

    A 

    END 

    Result: 

    B 

    REPLACE ECM 

    (Refer to REMOVAL [08/2015 - ] )

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