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Home >> Lexus >> 2010 >> IS 250C Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control (Diagnostic Codes (P0171-P062F) >> SFI System >> DTC P050A: Cold Start Idle Air Control System Performance >> Procedure
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DTC P050A: Cold Start Idle Air Control System Performance: 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 / 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.

    B → See step   17 

    A: Go to next step 

  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 / Data List / A/F Control System / Short FT #1 and Long FT #1, or Short FT #2 and Long FT #2.
    5. Read the values displayed on the Techstream at engine idle.
    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.

      OK

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

    NG → See step   7 

    OK: Go to next step 

  3. CHECK THROTTLE VALVE 
    1. Check for deposits around the throttle valve and throttle valve condition.

      OK

      No deposits around throttle valve and throttle valve moves smoothly.

    NG → See step   5 

    OK: Go to next step 

  4. REPLACE ECM 
    1. Replace the ECM. Refer to REMOVAL .

    NEXT → See step   6 

  5. REPAIR OR REPLACE THROTTLE BODY ASSEMBLY 
    1. Repair or replace the throttle body assembly. Refer to REMOVAL .

    NEXT: Go to next step 

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

    In this operation, the engine must be cold (the same level 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 .
    5. Turn the engine switch off.
    6. Turn the engine switch on (IG) and turn the Techstream on.
    7. Start the engine and warm it up.
    8. Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.
    9. Enter the following menus: Powertrain / Engine / Utility / All Readiness.
    10. Input the DTC: P050A.
    11. Check the DTC judgment result.

      OK

      DTC judgment result is NORMAL.

    NEXT → END 

  7. PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE VVT SYSTEM (BANK 1 OR BANK 2)) 
    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 / 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 assembly 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 assembly switched from off to on)

    NG → See step   12 

    OK: Go to next step 

  8. CHECK PCV HOSE (HOSE CONNECTIONS) 
    1. Check the PCV hose connections. Refer to ON-VEHICLE INSPECTION .

      OK

      PCV hose is connected correctly and is not damaged.

    NG → See step   13 

    OK: Go to next step 

  9. CHECK INTAKE SYSTEM 
    1. Check the intake system for vacuum leaks. Refer to ON-VEHICLE INSPECTION - Step 1 .

      OK

      No leaks in the intake system.

    NG → See step   14 

    OK: Go to next step 

  10. 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.

    NG → See step   15 

    OK: Go to next step 

  11. REPLACE MASS AIR FLOW METER 
    1. Replace the mass air flow meter. Refer to REMOVAL .

    NEXT → See step   16 

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

    NEXT → See step   16 

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

    NEXT → See step   16 

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

    NEXT → See step   16 

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

    NEXT → See step   16 

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

    In this operation, the engine must be cold (the same level 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 .
    5. Turn the engine switch off.
    6. Turn the engine switch on (IG) and turn the Techstream on.
    7. Start the engine and warm it up.
    8. Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.
    9. Enter the following menus: Powertrain / Engine / Utility / All Readiness.
    10. Input the DTC: P050A.
    11. Check the DTC judgment result.

      OK

      DTC judgment result is NORMAL.

    NEXT → END 

  17. GO TO DTC CHART. Refer to  DIAGNOSTIC TROUBLE CODE CHART 
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