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Home >> Toyota >> 2012 >> Avalon Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (Diagnostic Codes (P0351-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 Techstream to the DLC3.
    2. Turn the ignition switch to ON.
    3. Turn the Techstream on.
    4. Select the following the menu items: 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   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 Techstream to the DLC3.
    2. Start the engine.
    3. Turn the Techstream on.
    4. Select the following menu items: Powertrain / Engine / Data List / All Data / Short FT #1, Long FT #1, 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 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%.

    NG → See step   5 

    OK: Go to next step 

  3. INSPECT THROTTLE BODY ASSEMBLY (THROTTLE VALVE) 
    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

      Result Proceed to
      NG A
      OK B

    B → See step   14 

    A: Go to next step 

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

    NEXT → See step   14 

  5. CHECK PCV SYSTEM 
    1. Check the PCV hose connections. Refer to ON-VEHICLE INSPECTION - Step 5 .

      OK

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

    NG → See step   10 

    OK: Go to next step 

  6. CHECK AIR INDUCTION SYSTEM 
    1. Check the air induction system for vacuum leaks.

      OK

      No leaks from the air induction system.

    NG → See step   11 

    OK: Go to next step 

  7. CHECK 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.

    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) 
    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 / Data List / All Data / 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 12 g/sec. and 17 g/sec. (shift lever: N; A/C: Off).

    OK → See step   14 

    NG → See step   15 

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

    NEXT → See step   14 

  11. REPAIR OR REPLACE AIR INDUCTION SYSTEM 
    1. Repair or replace the air induction system.

    NEXT → See step   14 

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

    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 Techstream to the DLC3.
    2. Turn the ignition switch to ON.
    3. Turn the Techstream on.
    4. Clear the 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 and turn the Techstream on.
    7. Enter the following menus: Powertrain / Engine / Data List / All Data / Coolant Temp.
    8. Check that the engine coolant temperature is between -10 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 the Confirmation Driving Pattern.
    11. Enter the following menus: Powertrain / Engine / Trouble Codes / Pending.
    12. Read the pending DTCs.

      Result

      Result Proceed to
      DTC is not output A
      DTC P050A is output B

    B → See step   15 

    A → END 

  15. 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 .

      HINT: 

      Repair any problems.

    NEXT: Go to next step 

  16. 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 Techstream to the DLC3.
    2. Turn the ignition switch to ON.
    3. Turn the Techstream on.
    4. Clear the 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 and turn the Techstream on.
    7. Enter the following menus: Powertrain / Engine / Data List / All Data / Coolant Temp.
    8. Check that the engine coolant temperature is between -10 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 the Confirmation Driving Pattern.
    11. Enter the following menus: Powertrain / Engine / Trouble Codes / Pending.
    12. Read the pending DTCs.
      RESULT

      Result Proceed to
      DTC P050A is output A
      DTC is not output B

    B → END 

    A: Go to next step 

  17. 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
      B50-72 (VG) - B10-5 (VG) Always Below 1 Ω
      B50-73 (E2G) - B10-4 (E2G) Always Below 1 Ω
      B50-72 (VG) or B10-5 (VG) - Body ground Always 10 kΩ or higher
    4. Reconnect the mass air flow meter connector.
    5. Reconnect the ECM connector.

    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.

      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.

    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 Techstream to the DLC3.
    2. Turn the ignition switch to ON.
    3. Turn the Techstream on.
    4. Clear the 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 and turn the Techstream on.
    7. Enter the following menus: Powertrain / Engine / Data List / All Data / Coolant Temp.
    8. Check that the engine coolant temperature is between -10 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 the Confirmation Driving Pattern.
    11. Enter the following menus: Powertrain / Engine / Trouble Codes / Pending.
    12. Read the pending DTCs.
      RESULT

      Result Proceed to
      DTC is not output A
      DTC P050A is output B

    B → See step   21 

    A → END 

  20. GO TO DTC CHART. Refer to  DIAGNOSTIC TROUBLE CODE CHART  .
  21. REPLACE ECM. Refer to  REMOVAL  .
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