LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Lexus >> 2013 >> RX 350 Base, AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (Diagnostic Codes (P0505 - P1603)) >> SFI System >> DTC P050A: Cold Start Idle Air Control System Performance (03/2012 - 07/2012) >> Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

DTC P050A: Cold Start Idle Air Control System Performance (03/2012 - 07/2012): Procedure

  1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P050A) 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Enter the following menus: Powertrain / Engine / 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   21 

    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. Start the engine.
    3. Turn the Techstream on.
    4. Enter the following menus: Powertrain / Engine / Data List / Short FT #1, Long FT #1, Short FT #2 and Long FT #2.
    5. Read the values displayed on the Techstream while the engine is idling.
    6. The total of the Short FT #1 and Long FT #1 values, and the Short FT #2 and Long FT #2 values to obtain the total fuel trim.

      Result

      The total of Short FT #1 and Long FT #1 values, and the total of Short FT #2 and Long FT #2 values is between -20% and 20%.

    NG → See step   5 

    OK: Go to next step 

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

      OK

      No deposits around throttle valve and throttle valve moves smoothly.

      Result

      Result Proceed to
      NG A
      OK B

    B → See step   14 

    A: Go to next step 

  4. REPAIR OR REPLACE THROTTLE WITH MOTOR BODY ASSEMBLY 
    1. Repair or replace the throttle with motor body assembly. Refer to REMOVAL [03/2012 - 07/2012] .

    NEXT → See step   14 

  5. CHECK PCV SYSTEM 
    1. Check the PCV hose connections. Refer to COMPONENTS [03/2012 - ] .

      OK

      PCV hose is connected correctly and is not damaged.

    NG → See step   10 

    OK: Go to next step 

  6. CHECK INTAKE SYSTEM 
    1. Check the intake system for vacuum leaks.

      OK

      No leakage from intake system.

    NG → See step   11 

    OK: Go to next step 

  7. CHECK 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 sub-assembly is not excessively contaminated with dirt or oil.

    NG → See step   12 

    OK: Go to next step 

  8. PERFORM ACTIVE TEST USING TECHSTREAM (OPERATE CAMSHAFT TIMING OIL CONTROL VALVE ASSEMBLY) 
    1. Operate the VVT system through the Active test, and check if the VVT system is operating normally.
      1. Perform the Active Test, referring to DTC P0011 Inspection Procedure (VVT system for intake camshaft). Refer to INSPECTION PROCEDURE .
      2. Perform the Active Test, referring to DTC P0014 Inspection Procedure (VVT system for exhaust camshaft). Refer to INSPECTION PROCEDURE .

    NG → See step   13 

    OK: Go to next step 

  9. READ VALUE USING TECHSTREAM (MAF). Refer to  PROCEDURE - Step 6 

    OK → See step   14 

    NG → See step   15 

  10. REPAIR OR REPLACE PCV SYSTEM 
    1. Repair or replace PCV system.

    NEXT → See step   14 

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

    NEXT → See step   14 

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

    NEXT → See step   14 

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

      HINT: 

    NEXT: Go to next step 

  14. CHECK WHETHER DTC OUTPUT RECURS (P050A) 
    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 engine switch on (IG).
    3. Turn the Techstream on.
    4. Clear the DTCs. Refer to DTC CHECK / CLEAR [03/2012 - 07/2012] .
    5. Turn the engine switch off and wait for 30 seconds.
    6. Turn the engine switch on (IG) and turn the Techstream on.
    7. Enter the following menus: Powertrain / Engine / Data List / Coolant Temp.
    8. Check that the engine coolant temperature is between -10 and 50°C (14 and 122°F).
    9. Start the engine and warm it up.
    10. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
    11. Enter the following menus: Powertrain / Engine / Utility / All Readiness.
    12. Input the DTC: P050A.
    13. Check the DTC judgment result.
      RESULT

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

    B → See step   15 

    A → See step   22 

  15. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY CONNECTOR CONNECTION) 
    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 [03/2012 - ] .

      HINT: 

      Repair any problems.

    NEXT: Go to next step 

  16. 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 engine switch on (IG).
    3. Turn the Techstream on.
    4. Clear the DTCs. Refer to DTC CHECK / CLEAR [03/2012 - 07/2012] .
    5. Turn the engine switch off and wait for 30 seconds.
    6. Turn the engine switch on (IG) and turn the Techstream on.
    7. Enter the following menus: Powertrain / Engine a / Data List / Coolant Temp.
    8. Check that the engine coolant temperature is between -10 and 50°C (14 and 122°F).
    9. Start the engine and warm it up.
    10. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
    11. Enter the following menus: Powertrain / Engine / Utility / All Readiness.
    12. Input the DTC: P050A.
    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 

  17. CHECK HARNESS AND CONNECTOR (MAS AIR FLOW METER SUB-ASSEMBLY - ECM). Refer to  PROCEDURE - Step 3 

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  18. REPLACE MASS AIR FLOW METER SUB-ASSEMBLY 
    1. Replace the mass air flow meter sub-assembly. Refer to REMOVAL [03/2012 - ] .

      HINT: 

      If the result of the inspection performed in step 9 indicated no problem, proceed to the next step without replacing the mass air flow meter sub-assembly.

    NEXT: Go to next step 

  19. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED 
    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 engine switch on (IG).
    3. Turn the Techstream on.
    4. Clear the DTCs. Refer to DTC CHECK / CLEAR [03/2012 - 07/2012] .
    5. Turn the engine switch off and wait for 30 seconds.
    6. Turn the engine switch on (IG) and turn the Techstream on.
    7. Enter the following menus: Powertrain / Engine / Data List / Coolant Temp.
    8. Check that the engine coolant temperature is between -10 and 50°C (14 and 122°F).
    9. Start the engine and warm it up.
    10. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
    11. Enter the following menus: Powertrain / Engine / Utility / All Readiness.
    12. Input the DTC: P050A.
    13. 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 → END 

  20. REPLACE ECM. Refer to  REMOVAL [03/2012 - 07/2012] 
  21. GO TO DTC CHART. Refer to  DIAGNOSTIC TROUBLE CODE CHART [03/2012 - 07/2012] 
  22. CHECK FOR INTERMITTENT PROBLEMS. Refer to  CHECK FOR INTERMITTENT PROBLEMS [03/2012 - ] 
scientia non olet · About LEMON Manuals