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Home >> Toyota >> 2007 >> Yaris Base, 2D Hatchback, Automatic >> Repair and Diagnosis >> Engine Performance >> Engine Control System >> SFI System >> DTC P050A, P050B: Cold Start Idle Air Control System Performance; Cold Start Ignition Timing Performance >> Inspection Procedure
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Inspection Procedure

HINT:

Read freeze frame data using an intelligent tester. Freeze frame data record the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data, from the time the malfunction occurred.

  1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P050A AND/OR P050B) 
    1. Connect an intelligent tester to the DLC3.
    2. Turn the ignition switch to ON.
    3. Turn the tester ON.
    4. Select the following the menu items: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
    5. Read the DTCs.

      Result 

      RESULT REFERENCE

      Display (DTC Output) Proceed To
      P050A and/or P050B A
      P050A and/or P050B and other DTCs B

      HINT:

      If any DTCs other than P050A and P050B are output, troubleshoot those DTCs first.

    B: GO TO  DTC TABLE  

    A: GO TO NEXT STEP 

  2. READ VALUE USING INTELLIGENT TESTER (FUEL TRIM) 

    HINT:

    Calculate the total fuel trim values to check the characteristic deviation of the mass air flow meter.

    1. Connect the intelligent tester to the DLC3.
    2. Turn the ignition switch to ON.
    3. Turn the tester ON.
    4. Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / SHORT FT#1 and LONG FT #1.
    5. Read the values displayed on the tester.
    6. Add together the SHORT FT #1 and LONG FT #1 values to obtain the total FUEL TRIM.

      OK: Total of SHORT FT #1 and LONG FT #1 values is between -20% and 20%. 

    OK: Go to step   12 

    NG: GO TO NEXT STEP 

  3. PERFORM ACTIVE TEST USING INTELLIGENT TESTER (OPERATE OCV) 
    1. Connect the intelligent tester to the DLC3.
    2. Start the engine and turn the tester ON.
    3. Warm up the engine.
    4. Select the following menu items: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / WT CTRL B1.
    5. Check the engine speed while operating the Oil Control Valve (OCV) using the tester.

      OK 

      ACTIVE TEST REFERENCE

      Tester Operations Specified Conditions
      OCV OFF Normal engine speed
      OCV ON Engine idles roughly or stalls (soon after OCV switched from OFF to ON)

    NG: Go to step   8 

    OK: GO TO NEXT STEP 

  4. CHECK PCV HOSE CONNECTIONS 

    OK: PCV hose is connected correctly and is not damaged. 

    NG: Go to step   9 

    OK: GO TO NEXT STEP 

  5. CHECK AIR INDUCTION SYSTEM 
    1. Check the air induction system for vacuum leakage.

      OK: No leakage from air induction system. 

    NG: Go to step   10 

    OK: GO TO NEXT STEP 

  6. 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: Go to step   11 

    OK: GO TO NEXT STEP 

  7. REPLACE MASS AIR FLOW METER 

    NEXT: Go to step   15 

  8. CHECK AND REPAIR WT SYSTEM 

    NEXT: Go to step   15 

  9. REPAIR OR REPLACE PCV HOSE 

    NEXT: Go to step   15 

  10. REPAIR OR REPLACE AIR INDUCTION SYSTEM 

    NEXT: Go to step   15 

  11. REPLACE AIR CLEANER FILTER ELEMENT SUB-ASSEMBLY 

    NEXT: Go to step   15 

  12. 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: Go to step   14 

    OK: GO TO NEXT STEP 

  13. REPLACE ECM 

    NEXT: Go to step   15 

  14. REPAIR OR REPLACE THROTTLE BODY ASSEMBLY 

    NEXT: Go to step   15 

  15. CHECK WHETHER DTC OUTPUT RECURS (DTC P050A AND/OR P050B) 
    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 intelligent tester to the DLC3.
    2. Turn the ignition switch to ON.
    3. Turn the tester ON.
    4. Clear DTCs (See DTC CHECK/CLEAR  ).
    5. Switch the ECM from normal mode to check mode using the tester (See CHECK MODE PROCEDURE  ).
    6. Start the engine to idle for a minute.

      OK: Stable fast idling. 

    7. Read DTCs.

      OK: No DTC output.