Mike's Workshop Manuals: Service manuals for every vehicle
Home >> Lexus >> 2009 >> LX 570 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control (Diagnostic Codes (P0455-P2A00) & Circuit Tests) >> SFI System >> DTC P050A: Cold Start Idle Air Control System Performance >> Procedure

DTC P050A: Cold Start Idle Air Control System Performance: Procedure

  1. CHECK DTCS 

    OK

    Any other DTCs are not output.

    NG → See step   16 

    OK: 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. Turn the engine switch on (IG) and turn the Techstream on.
    3. Enter the following menus: Powertrain / Engine and ECT / Data List / A/F Control System / Short FT #1 and Long FT #1, or Short FT #2 and Long FT #2.
    4. Read the values displayed on the Techstream.
    5. 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.

      Result

      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   4 

    OK: Go to next step 

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

      OK

      No deposits around throttle valve and throttle valve moves smoothly.

    OK → See step   9 

    NG → See step   8 

  4. CHECK VVT SYSTEM 
    1. Allow the engine to idle after the engine is warmed up.
    2. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the VVT System (Bank 1) or Control the VVT System (Bank 2).
    3. Turn on Control the VVT System (Bank 1) or Control the VVT System (Bank 2) to advance the valve timing.
    4. Check the engine condition.

      OK

      The engine stalls or idles roughly when Control the VVT System is ON (VVT system is OK).

    NG → See 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 speed.

      OK

      The engine speed rises when the PCV hose is pinched.

    NG → See 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 → See step   12 

    OK: Go to next step 

  7. CHECK AIR INDUCTION SYSTEM 
    1. Check the air induction system for vacuum leakage. Refer to ON-VEHICLE INSPECTION - Step 4 .

    OK → See step   14 

    NG → See step   13 

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

    NEXT → See step   15 

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

    NEXT → See step   15 

  10. CHECK AND REPAIR VVT SYSTEM 

    NEXT → See step   15 

  11. REPAIR OR REPLACE PCV HOSE 

    NEXT → See step   15 

  12. REPLACE AIR CLEANER FILTER 

    NEXT → See step   15 

  13. REPAIR OR REPLACE AIR INDUCTION SYSTEM 

    NEXT → See step   15 

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

    NEXT: Go to next step 

  15. CHECK DTCS 
    1. Check that the engine coolant temperature is -10 to 50°C (14 to 122°F).
    2. Clear the DTC. Refer to DTC CHECK / CLEAR .
    3. Enter the check mode using the Techstream. Refer to CHECK MODE PROCEDURE .
    4. Allow the engine to idle for 1 minute.
    5. Check that no DTC is output.

    NEXT → END 

  16. GO TO DIAGNOSTIC TROUBLE CODE CHART. Refer to  DIAGNOSTIC TROUBLE CODE CHART