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Home >> Toyota >> 2010 >> Prius Base >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Control (SFI) System (Diagnostic Codes (P0300-P106A)) (Except PHV) >> 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 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   22 

    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).
    3. Turn the Techstream on.
    4. Enter the following menus: Powertrain / Engine and ECT / Data List / Short FT #1 and Long FT #1.
    5. Read the values displayed on the Techstream.
    6. Add together the Short FT #1 and Long FT #1 values to obtain the total Fuel Trim.

      OK

      Total of Short FT #1 and Long FT #1 values is between -20% and 20%.

    NG → See step   9 

    OK: Go to next step 

  3. INSPECT THROTTLE BODY ASSEMBLY 
    1. Check that there are no deposits around the throttle valve.

      OK

      No deposits around the throttle valve.

    NG → See step   7 

    OK: Go to next step 

  4. PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE EGR VALVE 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 the Active Test.
      • Be sure to return the EGR valve to step 0 when the Active Test is completed.
      • Do not open the EGR valve 30 steps or more during the Active Test.

      OK

      MAP and idling condition change in response to EGR step position when Throttle Idle Position is ON in Data List.

      Standard

      - EGR Step Position (Active Test)
      0 Steps 0 to 30 Steps
      Idling condition Steady idling Idling changes from steady to rough idling
      MAP
      (Data List)      		 MAP value is 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 the EGR valve.

      Result

      Result Proceed to
      Outside of standard range A
      Within standard range B

    B → See step   6 

    A: Go to next step 

  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 .

    NG → See step   19 

    OK: Go to next step 

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

    NEXT → See step   8 

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

    NEXT → See step   8 

  8. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED 
    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 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. Start the engine and warm it up.
    9. Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.
    10. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
    11. Input the DTC: P050A.
    12. Check the DTC judgment result.

    NEXT → END 

  9. CHECK PCV HOSE 
    1. Check the PCV hose connections.

      OK

      PCV hose is connected correctly and is not damaged.

    NG → See step   16 

    OK: Go to next step 

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

      OK

      No leaks from the intake system.

    NG → See step   17 

    OK: Go to next step 

  11. 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

      The air cleaner filter element sub-assembly is not excessively contaminated with dirt or oil.

    NG → See step   18 

    OK: Go to next step 

  12. PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE EGR VALVE 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 the Active Test.
      • Be sure to return the EGR valve to step 0 when the Active Test is completed.
      • Do not open the EGR valve 30 steps or more during the Active Test.

      OK

      MAP and idling condition change in response to EGR step position when Throttle Idle Position is ON in Data List.

      Standard

      - EGR Step Position (Active Test)
      0 Steps 0 to 30 Steps
      Idling condition Steady idling Idling changes from steady to rough idling
      MAP
      (Data List)      		 MAP value is 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 the EGR valve.

      Result

      Result Proceed to
      Outside of standard range A
      Within standard range B

    B → See step   14 

    A: Go to next step 

  13. 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   19 

    OK: Go to next step 

  14. PERFORM ACTIVE TEST USING TECHSTREAM (OPERATE CAMSHAFT TIMING OIL CONTROL VALVE ASSEMBLY) 
    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.
    6. Turn the Techstream on.
    7. Warm up the engine.
    8. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the VVT System (Bank 1).
    9. Check the engine speed while operating the camshaft timing oil control valve assembly using the Techstream.

      Result

      Techstream Operation Specified Condition
      OFF Normal engine speed
      ON Engine idles roughly or stalls
      (soon after camshaft timing oil control valve assembly switched from OFF to ON)

      HINT: 

      If the result is not acceptable, cool the engine and perform the Active Test again.

    10. Start the engine when the engine coolant temperature is 30°C (86°F) or less.
    11. Turn the Techstream on.
    12. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the VVT System (Bank 1).
    13. Check the engine speed while operating the camshaft timing oil control valve assembly using the Techstream with the engine coolant temperature at 50°C (122°F) or less.

      Result

      Techstream Operation Specified Condition
      OFF Normal engine speed
      ON Engine idles roughly or stalls
      (soon after camshaft timing oil control valve assembly switched from OFF to ON)

    NG → See step   20 

    OK: Go to next step 

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

    NEXT → See step   21 

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

    NEXT → See step   21 

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

    NEXT → See step   21 

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

    NEXT → See step   21 

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

    NEXT → See step   21 

  20. CHECK AND REPAIR VVT SYSTEM 

    HINT: 

    Check the VVT system.

    NEXT: Go to next step 

  21. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED (DTC P050A) 
    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 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. Start the engine and warm it up.
    9. Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.
    10. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
    11. Input the DTC: P050A.
    12. Check the DTC judgment result.

    NEXT → END 

  22. GO TO DTC CHART. Refer to  DIAGNOSTIC TROUBLE CODE CHART 
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