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Home >> Lexus >> 2007 >> SC 430 >> Repair and Diagnosis >> Engine Performance >> Engine Control System >> SFI System >> DTC P050A Cold Start Idle Air Control System Performance >> Inspection Procedure
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Inspection Procedure

  1. CHECK DTCS 

    Result: 

    Any other DTCs are not set. 

    NG: GO TO DIAGNOSTIC TROUBLE CODE CHART 

    OK: Go to next step 

  2. READ SHORT-TERM AND LONG-TERM FUEL TRIMS 

    HINT:

    The total of the short-term fuel trim (SHORT FT) and long-term fuel trim (LONG FT) is used to discover a problem in the induction system (between air cleaner and intake manifold).

    1. Allow the engine to idle.
    2. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY.
    3. Read the value of SHORT FT #1 and LONG FT #1 (bank 1).
    4. Read the value of SHORT FT #2 and LONG FT #2 (bank 2).

      Result: 

      Total of SHORT FT and LONG FT is between -20% and 20% 

    NG: Go to step  4

    OK: Go to next step 

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

      Result: 

      No deposits around throttle valve and throttle valve moves smoothly. 

    NG: Go to step  8

    OK: Go to step  9

  4. CHECK VVT SYSTEM 
    1. Allow the engine to idle with the engine warmed up.
    2. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / VVT CTRL B1 (or VVT CTRL B2).
    3. Turn on VVT CTRL B1 (or VVT CTRL B2) to advance the valve timing.
    4. Check the engine condition.

      Result: 

      The engine stalls or idles roughly when VVT CTRL is ON. (VVT system is OK) 

    NG: Go to step  10

    OK: Go to next step 

  5. CHECK PCV SYSTEM 
    1. Allow the engine to idle.
    2. Pinch the positive crankcase ventilation (PCV) hose.
    3. Check the engine rpm.

      Result: 

      The engine rpm rises when the PCV hose is pinched. 

    NG: Go to step  11

    OK: Go to next step 

  6. CHECK AIR CLEANER FILTER 
    1. Visually check that the air cleaner filter is not excessively contaminated with dirt or oil.

    NG: Go to step  12

    OK: Go to next step 

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

    NG: Go to step  13

    OK: Go to step  14

  8. REPAIR OR REPLACE THROTTLE BODY 

    NEXT: Go to step  15

  9. REPLACE ECM 

    NEXT: Go to step  15

  10. CHECK AND REPAIR VVT SYSTEM 

    NEXT: Go to step  15

  11. REPAIR OR REPLACE PCV HOSE 

    NEXT: Go to step  15

  12. REPLACE AIR CLEANER FILTER 

    NEXT: Go to step  15

  13. REPAIR OR REPLACE AIR INDUCTION SYSTEM 

    NEXT: Go to step  15

  14. REPLACE MASS AIR FLOW METER 

    NEXT: Go to step 15 

  15. CHECK DTCS 
    1. Check that the engine coolant temperature is -10 to 50°C (14 to 122°F).
    2. Clear the DTC.
    3. Enter the check mode using the intelligent tester.
    4. Allow the engine to idle for 1 minute.
    5. Check that no DTC is present.

    NEXT: END 

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