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Home › Toyota › 2006 › Prius › Repair and Diagnosis › Engine Performance › Engine Control System (1NZ-FXE) › SFI System › DTC P0446 Evaporative Emission Control System Vent Control Circuit › Inspection Procedure

Inspection Procedure

  1. CONFIRM DTC 
    1. Turn the power switch OFF and wait for 10 seconds.
    2. Turn the power switch ON (IG).
    3. Turn the power switch OFF and wait for 10 seconds.
    4. Connect the intelligent tester to the DLC3.
    5. Turn the power switch ON (IG).
    6. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
    7. Check if DTC P0446 is output.

    NO : Go to step   5 

    YES : GO TO NEXT STEP 

  2. PERFORM EVAP SYSTEM CHECK 
    1. Note the freeze frame data and DTCs.
    2. Clear DTCs.
    3. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / SYSTEM CHECK / EVAP SYS CHECK / AUTO OPERATION.
    4. After the system check is finished, check for pending DTCs.

      OK : No DTC is present. 

    NG : Go to step   6 

    OK : GO TO NEXT STEP 

  3. CHECK OPERATION FOR PRESSURE SWITCHING VALVE 
    1. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / TANK BYPASS VSV.
    2. Touch the pressure switching valve (TANK BYPASS VSV) to feel the operating vibration.

      OK : The pressure switching valve is operated by the ACTIVE TEST. 

    NG : Go to step   18 

    OK : GO TO NEXT STEP 

  4. CHECK PRESSURE SWITCHING VALVE 
    1. Turn the power switch OFF.
    2. Remove the pressure switching valve (see REMOVAL ).
    3. Reconnect the pressure switching valve connector.
    4. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / TANK BYPASS VSV.
    5. Check the airflow for the pressure switching valve.

      OK : The pressure switching valve operates normally. 

    NG : Go to step   19 

    Fig 1: Removing Pressure Switching Valve
    G04472068Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK : Go to step   33 

  5. PERFORM EVAP SYSTEM CHECK 
    1. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / SYSTEM CHECK / EVAP SYS CHECK / AUTO OPERATION.
    2. After the system check is finished, check for pending DTCs.

      OK; DTCs are present. 

    NG : CHECK INTERMITTENT PROBLEMS 

    OK : GO TO NEXT STEP 

  6. CHECK DTC 
    1. Check the DTCs that were present at the EVAP system check.

      OK : P043E, P043F, P2401, P2402 and P2419 are present. 

    NG : Go to step   10 

    OK : GO TO NEXT STEP 

  7. CHECK VENT VALVE CLOSE STUCK 
    1. Allow the engine to idle.
    2. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / EVAP VSV.
    3. Turn the EVAP VSV ON (purge VSV open) and check the VAPOR PRESS (EVAP pressure) for 10 seconds.

      OK : EVAP pressure is higher than 755 mmHg. 

    NG : Go to step   20 

    OK : GO TO NEXT STEP 

  8. CHECK LEAK DETECTION PUMP OPERATION 
    1. Turn the power switch OFF.
    2. Turn the power switch ON (IG).
    3. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / VACUUM PUMP.
    4. Touch the pump module to feel the operating vibration.

      OK : The leak detection pump is operated by the ACTIVE TEST. 

    NG : Go to step   21 

    OK : GO TO NEXT STEP 

  9. CHECK TRAP CANISTER 
    1. Disconnect the vent hose from the pump module.
    2. Check that no moisture is in the pump module or the vent hose.

      OK : No moisture. 

    OK : Go to step   22 

    NG : Go to step   23 

    Fig 2: View Of Vent Hose And Pump Module
    G04472069Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  10. CHECK DTC 
    1. Check the DTCs that were present at the EVAP system check.

      OK : P0441, P0455 and/or P0456 are present. 

    NG : Go to step   16 

    NG : GO TO NEXT STEP 

  11. CHECK INSTALLATION FOR FUEL CAP 
    1. Remove the fuel cap.
    2. Reinstall the fuel cap.
    3. Clear DTCs.
    4. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / SYSTEM CHECK / EVAP SYS CHECK / AUTO OPERATION.
    5. After the system check is finished, check for pending DTCs.

      HINT:

      If no DTC is present, this indicates that the fuel cap is loosened.

      OK : No DTC is present. 

    OK : REPAIR COMPLETED 

    NG : GO TO NEXT STEP 

  12. LOCATE LEAK POINT 
    1. Disconnect the vent hose (fresh air line) as shown in the illustration.
      Fig 3: Disconnecting Vent Hose
      G04472070Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Connect the pressure gauge and air pump as shown in the illustration.
    3. Pressurize the EVAP system until 24 to 28 mmHg.
    4. Locate the leak point.

      HINT:

      If the EVAP system has leakage, a whistling sound may be heard.

      OK : The leak point is found. 

    OK : Go to step   24 

    NG : GO TO NEXT STEP 

  13. CHECK FUEL CAP 

    Check that the fuel cap meets OEM specifications.

    HINT:

    If an EVAP tester is available, perform the fuel cap test according to the tester's instructions.

    OK : Fuel cap meets OEM specifications. 

    NG : Go to step   25 

    OK : GO TO NEXT STEP 

  14. CHECK OPERATION FOR PURGE VSV 
    1. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / EVAP VSV.
    2. Touch the purge VSV to feel the operating vibration.

      OK : The purge VSV (EVAP VSV) is operated by the ACTIVE TEST. 

    NG : Go to step   26 

    OK : GO TO NEXT STEP 

  15. CHECK INTAKE MANIFOLD PRESSURE 
    1. Disconnect the purge VSV hose that is connected to the throttle body.
    2. Allow the engine to idle.
    3. Check that the hose has suction using your finger.

      OK : The hose has suction. 

    NG : Go to step   27 

    Fig 4: Disconnecting Purge VSV Hose
    G04472071Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK : Go to step   28 

  16. CHECK DTC 
    1. Check the DTCs that were present at the EVAP system check.

      OK : P0451 is not present. 

    NG : Go to step   9 

    OK : GO TO NEXT STEP 

  17. CHECK OPERATION FOR VENT VALVE 
    1. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / VENT VALVE.
    2. Touch the pump module to feel the operating vibration.

      OK : The vent valve is operated by the ACTIVE TEST. 

    OK : Go to step   9 

    NG : Go to step   29 

  18. CHECK HARNESS AND CONNECTOR (PRESSURE SWITCHING VALVE - ECM AND EFI M RELAY) 
    1. Check the harness and the connectors between the pressure switching valve and the ECM.
      1. Disconnect the V8 pressure switching valve connector.
        Fig 5: Disconnecting V8 Pressure Switching Valve Connector
        G04472072Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      2. Disconnect the E7 ECM connector.
      3. Measure the resistance between the wire harness side connectors.

        Standard resistance Check for open) 

        Fig 6: Disconnecting E7 ECM Connector
        G04472073Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
        TESTER CONNECTION AND SPECIFIED CONDITION

        Tester Connection Specified Condition
        V8-1 (Pressure switching valve) - E7- 18 (TBP) Below 1 Ω

        Standard resistance (Check for short) 

        TESTER CONNECTION AND SPECIFIED CONDITION

        Tester Connection Specified Condition
        V8-1 (Pressure switching valve) or E7-18 (TBP) - Body ground 10 kΩ higher
      4. Reconnect the pressure switching valve connector.
      5. Reconnect the ECM connector.
    2. Check the harness and the connectors between the pressure switching valve and the EFI M relay.
      1. Disconnect the V8 pressure switching valve connector.
      2. Remove the integration relay from the engine room relay block.
      3. Measure the resistance between the wire harness side connector.

        Standard resistance (Check for open) 

        Fig 7: View Of Engine Room Relay Block - Integration Relay Shown
        G04471860Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
        TESTER CONNECTION AND SPECIFIED CONDITION

        Tester Connection Specified Condition
        V8-2 (Pressure switching valve) - 3I-8 (EFI M relay) Below 1 Ω

        Standard resistance (Check for short) 

        TESTER CONNECTION AND SPECIFIED CONDITION

        Tester Connection Specified Condition
        V8-2 (Pressure switching valve) or 3I- 8 (EFI M relay) - Body ground 10 kΩ or higher
      4. Reconnect the pressure switching valve connector.
      5. Reinstall the integration relay.

    NG : Go to step   30 

    OK : Go to step   31 

  19. REPLACE PRESSURE SWITCHING VALVE 

    Replace the pressure switching valve (see REMOVAL ).

    NEXT : Go to step   34 

  20. CHECK FOR VENT HOSE CLOG 
    1. Turn the power switch OFF.
    2. Disconnect the vent hose (fresh air line) as shown in the illustration.
    3. Allow the engine to idle.
    4. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / EVAP VSV.
    5. Turn the purge VSV (EVAP VSV) ON and check the EVAP pressure (VAPOR PRESS) for 10 seconds.

      OK : EVAP pressure is higher than 755 mmHg. 

      Fig 8: View Of Vent Hose And Pump Module
      G04472069Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG : Go to step   22 

    OK : Go to step   32 

  21. CHECK HARNESS AND CONNECTOR (LEAK DETECTION PUMP - ECM) 
    1. Disconnect the V7 canister connector
      Fig 9: Disconnecting V7 Canister Connector
      G04472076Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Disconnect the E7 ECM connector.
    3. Measure the resistance between the wire harness side connector.

      Standard resistance (Check for open) 

      TESTER CONNECTION AND SPECIFIED CONDITION

      Tester Connection Specified Condition
      V7-1 (MTRB) - E7-13 (MPMP) Below 1 Ω
      V7-6 (MGND) - Body ground Below 1 Ω

      Standard resistance (Check for short) 

      TESTER CONNECTION AND SPECIFIED CONDITION

      Tester Connection Specified Condition
      V7-1 (MTRB) or E7-13 (MPMP) - Body ground 10 kΩ higher
      Fig 10: Disconnecting E7 ECM Connector
      G04472077Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    4. Reconnect the canister connector.
    5. Reconnect the ECM connector.

    NG : Go to step   30 

    OK : Go to step   31 

  22. REPLACE TRAP CANISTER WITH PUMP MODULE 

    Replace the trap canister with pump module (See REMOVAL ).

    NEXT : Go to step   34 

  23. CHECK FOR VENT HOSE DAMAGE 

    Check for hose damage as shown in the illustration. If necessary, replace the vent hose.

    Fig 11: Checking Vent Hose
    G04472078Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NEXT : Go to step   22 

  24. REPAIR OR REPLACE LEAK POINT 

    NEXT : Go to step   34 

  25. REPLACE FUEL CAP 

    NEXT : Go to step   34 

  26. CHECK HARNESS AND CONNECTOR (PURGE VSV - ECM) 
    1. Disconnect the V1 purge VSV connector.
      Fig 12: Disconnecting V1 Purge VSV Connector
      G04472079Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Disconnect the E5 ECM connector.
    3. Check the harness and the connectors between the ECM and the purge VSV connectors.
      1. Measure the resistance between the wire harness side connector.

        Standard resistance (Check for open) 

        TESTER CONNECTION AND SPECIFIED CONDITION

        Tester Connection Specified Condition
        V1-1 - E5-14 (EVP1) Below 1 Ω
        Fig 13: Disconnecting E5 ECM Connector
        G04472080Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

        Standard resistance (Check for short) 

        TESTER CONNECTION AND SPECIFIED CONDITION

        Tester Connection Specified Condition
        V1-1 or E5-14 (EVP1) - Body ground 10 kΩ higher
    4. Remove the integration relay from the engine room relay block.
    5. Check the harness and connectors between the purge VSV connector and the EFI M relay.
      1. Measure the resistance between the wire harness side connectors.

        Standard resistance (Check for open) 

        TESTER CONNECTION AND SPECIFIED CONDITION

        Tester Connection Specified Condition
        V1-2 - 3I-8 (EFI M relay) Below 1 Ω
        Fig 14: View Of Engine Room Relay Block - Integration Relay Shown
        G04471860Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

        Standard resistance (Check for short) 

        TESTER CONNECTION AND SPECIFIED CONDITION

        Tester Connection Specified Condition
        V1-2 or 3I-8 (EFI M relay) - Body ground 10 kΩ higher
    6. Reconnect the purge VSV connector.
    7. Reconnect the ECM connector.
    8. Reinstall the integration relay.

    NG : Go to step   30 

    OK : Go to step   31 

  27. REPLACE HOSE (PURGE VSV - THROTTLE BODY) 

    NEXT : Go to step   34 

  28. REPLACE PURGE VSV 

    Replace the purge VSV (see REMOVAL ).

    NEXT : Go to step   34 

  29. CHECK HARNESS AND CONNECTOR (VENT VALVE - ECM) 
    1. Disconnect the V7 canister connector.
      Fig 15: Disconnecting V7 Canister Connector
      G04472082Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Disconnect the E7 ECM connector.
    3. Check the harness and the connectors between the ECM and the canister connectors.
      1. Measure the resistance between the wire harness side connector.

        Standard resistance (Check for open) 

        TESTER CONNECTION AND SPECIFIED CONDITION

        Tester Connection Specified Condition
        V7-8 (VGND) - E7-26 (VPMP) Below 1 Ω

        Standard resistance (Check for short) 

        TESTER CONNECTION AND SPECIFIED CONDITION

        Tester Connection Specified Condition
        V7-8 (VGND) or E7-26 (VPMP) - Body ground 10 kΩ higher
        Fig 16: Disconnecting E7 ECM Connector
        G04472083Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    4. Remove the integration relay from the engine room relay block.
    5. Check the harness and connectors between the canister connector and the EFI M relay.
      1. Measure the resistance between the wire harness side connectors.

        Standard resistance (Check for open) 

        TESTER CONNECTION AND SPECIFIED CONDITION

        Tester Connection Specified Condition
        V7-9 (VLVB) - 3I-8 (EFI M relay) Below 1 Ω
        Fig 17: View Of Engine Room Relay Block - Integration Relay Shown
        G04471860Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

        Standard resistance (Check for short) 

        TESTER CONNECTION AND SPECIFIED CONDITION

        Tester Connection Specified Condition
        V7-9 (VLVB) or 3I-8 (EFI M relay) - Body ground 10 kΩ higher
    6. Reconnect the canister connector.
    7. Reconnect the ECM connector.
    8. Reinstall the integration relay.

    NG : Go to step 30 

    OK : Go to step   31 

  30. REPAIR OR REPLACE HARNESS AND CONNECTOR 

    NEXT : Go to step   34 

  31. REPLACE ECM 

    Replace the ECM (see REMOVAL  ).

    NEXT : Go to step   34 

  32. CHECK AND REPLACE VENT HOSE OR CANISTER FILTER 

    NEXT : Go to step   34 

  33. REPLACE HOSE (PRESSURE SWITCHING VALVE AND FUEL TANK) 

    NEXT 

  34. PERFORM EVAP SYSTEM CHECK 
    1. Turn the power switch ON (IG).
    2. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / SYSTEM CHECK / EVAP SYS CHECK / AUTO OPERATION.
    3. After the system check is finished, check for pending DTCs.

      OK : No DTC is present. 

    NG : Go to step   6 

    OK : GO TO NEXT STEP 

  35. PERFORM EVAP MONITOR DRIVE PATTERN 
    1. Check that the following conditions are met:
      • Fuel level is 1/8 to 7/8.
      • Engine coolant temperature (ECT) is 4.4 to 35°C (40 to 95°F).
      • Intake air temperature (IAT) is 4.4 to 35°C (40 to 95°F).
      • Difference of ECT and IAT is less than 7°C (13°F).
    2. Enter the check mode. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / CHECK MODE.
    3. Allow the engine to idle until the ECT is 75°C (167°F).
    4. Drive the vehicle at 50 km/h (30 mph) or faster and maintain that speed for 60 seconds or more.
    5. Stop the vehicle. Do not turn the power switch OFF.
    6. Check that the EVAP monitor status is complete. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / MONITOR STATUS.
    7. If the EVAP monitor is incomplete, drive the vehicle at 50 km/h (30 mph) or faster and maintain that speed for 120 seconds or more. After that, recheck the EVAP monitor status.
    8. Check for pending DTCs.

      OK : No DTC is present. 

    NG : Go to step   2 

    OK : REPAIR COMPLETED 

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