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Home >> Lexus >> 2011 >> RX 450h 3.5 B >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (Diagnostic Codes (P0300-P1423) >> 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 the Techstream to the DLC3.
    2. Turn the power switch on (IG).
    3. Turn the Techstream on.
    4. Enter the following the menus: Powertrain / Engine and ECT / 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   25 

    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 sub-assembly.

    1. Connect the Techstream to the DLC3.
    2. Turn the power switch on (IG) and turn the Techstream on.
    3. Put the engine in inspection mode. Refer to INSPECTION MODE PROCEDURE .
    4. Start the engine.
    5. Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Short FT #1 and Long FT #1, or Short FT #2 and Long FT #2.
    6. Read the values displayed on the Techstream.
    7. 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.

      OK

      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   7 

    OK: Go to next step 

  3. INSPECT THROTTLE WITH MOTOR BODY ASSEMBLY 
    1. Check for deposits around the throttle valve and throttle valve condition.

      OK

      No deposits around throttle valve and throttle valve moves smoothly.

    NG → See step   6 

    OK: Go to next step 

  4. PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE EGR STEP POSITION) 
    1. Connect the Techstream to the DLC3.
    2. Turn the power switch on (IG).
    3. Turn the Techstream on.
    4. Put the engine in inspection mode. Refer to INSPECTION MODE PROCEDURE .
    5. Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or more.

      HINT: 

      The A/C switch and all accessory switches should be off.

    6. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the EGR Step Position.
    7. Confirm the Throttle Idle Position is ON and check the engine idling condition and MAP values in the Data List while performing the Active Test.

      HINT: 

      • Do not leave the EGR valve open for 10 seconds or more during Active Test.
      • Be sure to return the EGR valve to step 0 when Active Test is completed.

      OK

      MAP and idling condition change in response to EGR step position as follows.

      Standard

      - EGR Step Position (Active Test)
      0 Steps 0 to 30 Steps
      Idling condition Steady idling Idling changes from steady to rough idling or engine stall
      MAP
      (Data List)      		 20 to 40 kPa (150 to 300 mmHg)
      (EGR valve is fully closed)      		 MAP value is at least +10 kPa (75 mmHg) higher than when EGR valve is fully closed

      HINT: 

      During Active Test, if the idling condition does not change in response to EGR step position, then there is probably a malfunction in EGR valve.

    OK → See step   19 

    NG → See step   5 

  5. INSPECT EGR VALVE ASSEMBLY 
    1. Remove the EGR valve assembly. Refer to REMOVAL .
    2. Check if the EGR valve is stuck open.

      OK

      EGR valve is tightly closed.

    3. Reinstall the EGR valve assembly. Refer to INSTALLATION .

    OK → See step   19 

    NG → See step   17 

  6. REPAIR OR REPLACE THROTTLE WITH MOTOR BODY ASSEMBLY 
    1. Repair or replace the throttle with motor body assembly. Refer to REMOVAL .

    NEXT → See step   19 

  7. CHECK PCV HOSE 
    1. Check the PCV hose connections. Refer to ON-VEHICLE INSPECTION - Step 2 .

      OK

      PCV hose is connected correctly and is not damaged.

    NG → See step   14 

    OK: Go to next step 

  8. CHECK INTAKE SYSTEM 
    1. Check the intake system for vacuum leaks. Refer to ON-VEHICLE INSPECTION - Step 1 .

      OK

      No leaks in intake system.

    NG → See step   15 

    OK: Go to next step 

  9. INSPECT AIR CLEANER FILTER ELEMENT SUB-ASSEMBLY 
    1. Visually check that the air cleaner filter element sub-assembly is not excessively contaminated with dirt or oil.

      OK

      Air cleaner filter element is not excessively contaminated with dirt or oil.

    NG → See step   16 

    OK: Go to next step 

  10. PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE EGR STEP POSITION) 
    1. Connect the Techstream to the DLC3.
    2. Turn the power switch on (IG).
    3. Turn the Techstream on.
    4. Put the engine in inspection mode. Refer to INSPECTION MODE PROCEDURE .
    5. Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or more.

      HINT: 

      The A/C switch and all accessory switches should be off.

    6. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the EGR Step Position.
    7. Confirm the Throttle Idle Position is ON and check the engine idling condition and MAP values in the Data List while performing the Active Test.

      HINT: 

      • Do not leave the EGR valve open for 10 seconds or more during Active Test.
      • Be sure to return the EGR valve to step 0 when Active Test is completed.

      OK

      MAP and idling condition change in response to EGR step position as follows.

      Standard

      - EGR Step Position (Active Test)
      0 Steps 0 to 30 Steps
      Idling condition Steady idling Idling changes from steady to rough idling or engine stall
      MAP
      (Data List)      		 20 to 40 kPa (150 to 300 mmHg)
      (EGR valve is fully closed)      		 MAP value is at least +10 kPa (75 mmHg) higher than when EGR valve is fully closed

      HINT: 

      During Active Test, if the idling condition does not change in response to EGR step position, then there is probably a malfunction in EGR valve.

    OK → See step   12 

    NG → See step   11 

  11. INSPECT EGR VALVE ASSEMBLY 
    1. Remove the EGR valve assembly. Refer to REMOVAL .
    2. Check if the EGR valve is stuck open.

      OK

      EGR valve is tightly closed.

    3. Reinstall the EGR valve assembly. Refer to INSTALLATION .

    NG → See step   17 

    OK: Go to next step 

  12. PERFORM ACTIVE TEST USING TECHSTREAM (OPERATE CAMSHAFT TIMING OIL CONTROL VALVE) 
    1. Connect the Techstream to the DLC3.
    2. Turn the power switch on (IG) and turn the Techstream on.
    3. Put the engine in inspection mode. Refer to INSPECTION MODE PROCEDURE .
    4. Warm up the engine.
    5. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the VVT Linear (Bank 1) or Control the VVT Linear (Bank 2).
    6. Check the engine speed while operating the camshaft timing oil control valve assembly using the Techstream.

      OK

      Techstream Operation Engine Condition
      0% Normal engine speed
      100% Engine idles roughly or stalls

    NG → See step   18 

    OK: Go to next step 

  13. READ VALUE USING TECHSTREAM (MAF) 
    1. Connect the Techstream to the DLC3.
    2. Turn the power switch on (IG).
    3. Turn the Techstream on.
    4. Put the engine in inspection mode. Refer to INSPECTION MODE PROCEDURE .
    5. Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / MAF and Coolant Temp.
    6. Allow the engine to idle until Coolant Temp reaches 75°C (167°F) or higher.
    7. Read MAF with the engine speed at 2500 RPM.

      Standard

      Between 6 gm/sec and 17 gm/sec (shift lever: P).

      HINT: 

      when the vehicle is stopped, the engine is being raced with the accelerator pedal depressed 60% or more

    OK → See step   19 

    NG → See step   20 

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

    NEXT → See step   19 

  15. REPAIR OR REPLACE INTAKE SYSTEM 
    1. Repair or replace the intake system.

    NEXT → See step   19 

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

    NEXT → See step   19 

  17. REPLACE EGR VALVE ASSEMBLY 
    1. Replace the EGR valve assembly. Refer to REMOVAL .

    NEXT → See step   19 

  18. CHECK AND REPAIR VVT SYSTEM 
    1. Check and repair the VVT system.

    NEXT: Go to next step 

  19. CHECK WHETHER DTC OUTPUT RECURS 
    NOTE:

    In this operation, the engine must be cold (approximately the same level as the engine coolant temperature recorded in the freeze frame data).

    1. Connect the Techstream to the DLC3.
    2. Turn the power switch on (IG).
    3. Turn the Techstream on.
    4. Clear the DTCs. Refer to DTC CHECK / CLEAR .
    5. Turn the power switch off and wait for 30 seconds.
    6. Turn the power switch on (IG) and turn the Techstream on.
    7. Put the engine in inspection mode. Refer to INSPECTION MODE PROCEDURE .
    8. Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.
    9. Check that the engine coolant temperature is between -10°C and 50°C (14°F and 122°F).
    10. Start the engine.
    11. Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.
    12. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
    13. Input the DTC: P050A.
    14. Check the DTC judgment result.
      RESULT

      Result Proceed to
      NORMAL (DTC is not output) A
      ABNORMAL (DTC P050A is output) B

    B → See step   20 

    A → See step   26 

  20. CHECK HARNESS AND CONNECTOR 
    1. Check the connection and terminal contact pressure of connectors and wire harnesses between the mass air flow meter sub-assembly and ECM. Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE .

      HINT: 

      Repair any problems.

    NEXT: Go to next step 

  21. 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 the Techstream to the DLC3.
    2. Turn the power switch on (IG).
    3. Turn the Techstream on.
    4. Clear the DTCs. Refer to DTC CHECK / CLEAR .
    5. Turn the power switch off and wait for 30 seconds.
    6. Turn the power switch on and turn the Techstream on.
    7. Put the engine in inspection mode. Refer to INSPECTION MODE PROCEDURE .
    8. Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.
    9. Check that the engine coolant temperature is between -10°C and 50°C (14°F and 122°F).
    10. Start the engine.
    11. Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.
    12. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
    13. Check the DTC judgment result.
      RESULT

      Result Proceed to
      ABNORMAL (DTC P050A is output) A
      NORMAL (DTC is not output) B

    B → END 

    A: Go to next step 

  22. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM) 
    1. Disconnect the mass air flow meter sub-assembly 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
      D3-5 (VG) - D1-121 (VG) Always Below 1 Ω
      D3-4 (E2G) - D1-120 (E2G) Always Below 1 Ω
      D3-5 (VG) or D1-121 (VG) - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  23. REPLACE MASS AIR FLOW METER SUB-ASSEMBLY 
    1. Replace the mass air flow meter sub-assembly. Refer to REMOVAL .

      HINT: 

      If the result of the inspection performed in step 13 indicated no problem, proceed to the next step without replacing the mass air flow meter sub-assembly.

    NEXT: Go to next step 

  24. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED 
    NOTE:

    In this operation, the engine must be cold (approximately the same level as the engine coolant temperature recorded in the freeze frame data).

    1. Connect the Techstream to the DLC3.
    2. Turn the power switch on (IG).
    3. Turn the Techstream on.
    4. Clear the DTCs. Refer to DTC CHECK / CLEAR .
    5. Turn the power switch off and wait for 30 seconds.
    6. Turn the power switch on (IG) and turn the Techstream on.
    7. Put the engine in inspection mode. Refer to INSPECTION MODE PROCEDURE .
    8. Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.
    9. Check that the engine coolant temperature is between -10°C and 50°C (14°F and 122°F).
    10. Start the engine.
    11. Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.
    12. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
    13. Input the DTC: P050A.
    14. Check the DTC judgment result.
      RESULT

      Result Proceed to
      NORMAL (DTC is not output) A
      ABNORMAL (DTC P050A is output) B

    B → See step   27 

    A → END 

  25. GO TO DTC CHART. Refer to  DIAGNOSTIC TROUBLE CODE CHART 
  26. CHECK FOR INTERMITTENT PROBLEMS. Refer to  CHECK FOR INTERMITTENT PROBLEMS 
  27. REPLACE ECM. Refer to  REMOVAL 
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