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Home >> Scion >> 2012 >> xD Standard Trans >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (Diagnostic Codes (P0420-P1605)) >> 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 ignition switch to ON.
    3. Turn the Techstream on.
    4. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
    5. Read DTCs.
      RESULT

      Result Proceed to
      P050A A
      P050A and other DTCs B

      HINT: 

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

    B → See step   20 

    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 and ECT / Data List / Short FT #1 and Long FT #1.
    5. Read the values displayed on the Techstream.
    6. Add together the Short FT #1 and Long FT #1 values to obtain the total Fuel Trim.

      Standard

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

    NG → See step   5 

    OK: Go to next step 

  3. INSPECT THROTTLE BODY (THROTTLE VALVE) 
    1. Check 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.

    OK → See step   14 

    NG → See step   4 

  4. REPAIR OR REPLACE THROTTLE BODY 
    1. Repair or replace throttle body. Refer to REMOVAL .

    NEXT → See step   14 

  5. CHECK PCV HOSE CONNECTIONS 
    1. Check the PCV hose connections. Refer to COMPONENTS .

      OK

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

    NG → See step   10 

    OK: Go to next step 

  6. CHECK INTAKE SYSTEM 
    1. Check the intake system for vacuum leak. Refer to ON-VEHICLE INSPECTION .

      OK

      No leak from the intake system.

    NG → See step   11 

    OK: Go to next step 

  7. 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

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

    NG → See step   12 

    OK: Go to next step 

  8. PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE VVT 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 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 .

    NG → See step   13 

    OK: Go to next step 

  9. READ VALUE USING TECHSTREAM (MAF). Refer to  PROCEDURE - Step 6 

    OK → See step   14 

    NG → See step   15 

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

    NEXT → See step   14 

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

    NEXT → See step   14 

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

    NEXT → See step   14 

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

      HINT: 

    NEXT: Go to next step 

  14. 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 ignition switch to ON.
    3. Turn the Techstream on.
    4. Clear DTCs. Refer to DTC CHECK / CLEAR .
    5. Turn the ignition switch off and wait for at least 30 seconds.
    6. Turn the ignition switch to ON.
    7. Turn the Techstream on.
    8. Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.
    9. Check that the engine coolant temperature is between -10 and 50°C (14 and 122°F).
    10. Start the engine and warm it up.
    11. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
    12. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
    13. Input the DTC: P050A.
    14. Check the DTC judgment result.
      RESULT

      Result Proceed to
      NORMAL (No DTC output) A
      ABNORMAL (P050A is output) B

    B → See step   15 

    A → See step   21 

  15. 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 .

      HINT: 

      Repair any problems.

    NEXT: Go to next step 

  16. 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 ignition switch to ON.
    3. Turn the Techstream on.
    4. Clear DTCs. Refer to DTC CHECK / CLEAR .
    5. Turn the ignition switch off and wait for at least 30 seconds.
    6. Turn the ignition switch to ON.
    7. Turn the Techstream on.
    8. Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.
    9. Check that the engine coolant temperature is between -10 and 50°C (14 and 122°F).
    10. Start the engine and warm it up.
    11. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
    12. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
    13. Input the DTC: P050A.
    14. Check the DTC judgment result.
      RESULT

      Result Proceed to
      ABNORMAL (P050A is output) A
      NORMAL (No DTC output) B

    B → END 

    A: Go to next step 

  17. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM). Refer to  PROCEDURE - Step 3 

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

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

      HINT: 

      If the results of the inspections performed in step 9 indicated no problem, proceed to the next step without replacing the mass air flow meter.

    NEXT: Go to next step 

  19. 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 ignition switch to ON.
    3. Turn the Techstream on.
    4. Clear DTCs. Refer to DTC CHECK / CLEAR .
    5. Turn the ignition switch off and wait for at least 30 seconds.
    6. Turn the ignition switch to ON.
    7. Turn the Techstream on.
    8. Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.
    9. Check that the engine coolant temperature is between -10 and 50°C (14 and 122°F).
    10. Start the engine and warm it up.
    11. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
    12. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
    13. Input the DTC: P050A.
    14. Check the DTC judgment result.
      RESULT

      Result Proceed to
      NORMAL (No DTC output) A
      ABNORMAL (P050A is output) B

    B → See step   22 

    A → END 

  20. GO TO DTC CHART. Refer to  DIAGNOSTIC TROUBLE CODE CHART 
  21. CHECK FOR INTERMITTENT PROBLEMS. Refer to  CHECK FOR INTERMITTENT PROBLEMS 
  22. REPLACE ECM. Refer to  REMOVAL 
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