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Home >> Lexus >> 2007 >> LS 460L >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Diagnostic Codes (3 Of 4) >> DTC P050A Cold Start Idle Air Control System Performance; DTC P050B Cold Start Ignition Timing Performance >> Inspection Procedure
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Inspection Procedure

HINT:

Read freeze frame data using the Intelligent tester or Techstream. Freeze frame data records 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 the Intelligent tester or Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the tester ON.
    4. Enter the following menus:
      1. Intelligent tester - Select: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
      2. Techstream - Select: Powertrain / Engine / Trouble Codes.
    5. Read the DTCs.

      Result 

      ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P050A AND/OR P050B)

      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  DIAGNOSTIC TROUBLE CODE CHART 

    A: GO TO NEXT STEP 

  2. READ VALUE OF INTELLIGENT TESTER OR TECHSTREAM (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 or Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the tester ON.
    4. Enter the following menus:
      1. Intelligent tester - Select: DIAGNOSIS / ENHANCED OBD II / DATA LIST / A/F CONTROL SYS / SHORT FT #1 and LONG FT #1, or SHORT FT #2 and LONG FT #2.
      2. Techstream - Select: Powertrain / Engine / Data List / A/F Control System / Short FT #1 and Long FT #1, or Short FT #2 and Long FT #2.
    5. Read the values displayed on the tester.
    6. Add together the SHORT FT #1 (Short FT #1) and LONG FT #1 (Long FT #1), or SHORT FT #2 (Short FT #2) and LONG FT #2 (Long FT #2) values to obtain the total Fuel Trim.

      OK: Total of SHORT FT #1 (Short FT #1) and LONG FT #1 (Long FT #1), or SHORT FT #2 (Short FT #2) and LONG FT #2 (Long FT #2) values is between -20% and 20%. 

    OK: Go to step   12 

    NG: GO TO NEXT STEP 

  3. PERFORM ACTIVE TEST BY INTELLIGENT TESTER OR TECHSTREAM (MD VVT SYSTEM) 
    1. Connect the Intelligent tester or Techstream to the DLC3.
    2. Turn the engine switch on (IG) and turn the tester ON.
    3. Start the engine and warm it up.
    4. Engine is idling.
    5. Enter the following menus:
      1. Intelligent tester - Select: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / MD VVT B1 or MD VVT B2 / PRIMARY / MD VVT AIM ANG1 and VVT CHNG ANG#1 or MD VVT AIM ANG2 and VVT CHNG ANG#2.
      2. Techstream - Select: Powertrain/Engine/ Active Test / Control the MD VVT Linear (Bank 1) or Control the MD VVT Linear (Bank 2) / All Data / MD VVT Aim Angle (Bank 1) and VVT Change Angle (Bank 1) or MD VVT Aim Angle (Bank 2) and VVT Change Angle (Bank 2).
    6. Perform the Active Test operation with the engine speed at 1,500 rpm.

      OK 

      MD VVT SYSTEM

      Active Test Movement Order Difference between "MD VVT Aim Angle" and "VVT Change Angle"
      0 deg → 10 deg → 20 deg → 40 deg → 10 deg → 0 deg → 10 deg → END Within 4 DegFR

    NG: Go to step   8 

    OK: GO TO NEXT STEP 

  4. CHECK VENTILATION HOSE CONNECTIONS 

    OK: Ventilation 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 
    1. Replace the mass air flow meter (see REMOVAL ).

    NEXT: Go to step   15 

  8. CHECK AND REPAIR MD VVT SYSTEM 
    1. Check and repair the MD VVT System (see DISASSEMBLY ).

    NEXT: Go to step   15 

  9. REPAIR OR REPLACE VENTILATION HOSE 
    1. Repair or replace the ventilation hose (see ON-VEHICLE INSPECTION ).

    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 
    1. Replace the ECM (see REMOVAL ).

    NEXT: Go to step   15 

  14. REPAIR OR REPLACE THROTTLE BODY ASSEMBLY 
    1. Repair or replace the throttle body assembly (see REMOVAL ).

    NEXT 

  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 or Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    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. 

    NEXT: END 

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