SFI SYSTEM, Diagnostic DTC:P0441

DTC Code DTC Name
P0441 Evaporative Emission Control System Incorrect Purge Flow

DTC SUMMARY

DTC No. Monitoring Item DTC Detection Condition Trouble Area Detection Timing Detection Logic
P0441 Purge VSV (Vacuum Switching Valve) stuck open

Leak detection pump creates negative pressure (vacuum) in EVAP system and EVAP system pressure measured. Reference pressure is measured at start and at end of leak check.

If stabilized pressure higher than [second reference pressure standard x 0.2], ECM determines that purge VSV stuck open

  • Purge VSV

  • Connector/wire harness (Purge VSV - ECM)

  • ECM

  • Canister pump module

  • Leakage from EVAP system

 While power switch off 2 trip
P0441 Purge VSV stuck closed

After EVAP leak check performed, purge VSV turned on (open), and atmospheric air introduced into EVAP system. Reference pressure is measured at start and at end of the check.

If pressure does not return to near atmospheric pressure, ECM determines that purge valve stuck closed

  • Purge VSV

  • Purge line

  • Connector/wire harness (Purge VSV - ECM)

  • ECM

  • Canister pump module

  • Canister (filter inside canister clogged)

  • Leak from EVAP system

 While power switch off 2 trip
P0441 Purge flow

While engine running, following conditions successively met:


  • Negative pressure not created in EVAP system when purge VSV turned on (open)

  • EVAP system pressure change less than 0.5 kPa(gauge) [3.751 mmHg(gauge)] when vent valve turned on (closed)

  • Atmospheric pressure change before and after purge flow monitor less than 0.1 kPa(gauge) [0.75 mmHg(gauge)]

  • Purge VSV

  • Purge line

  • Connector/wire harness (Purge VSV - ECM)

  • ECM

  • Canister pump module

  • Canister (filter inside canister clogged)

  • Leak from EVAP system

 While engine running 2 trip

DESCRIPTION

The circuit description can be found in EVAP (Evaporative Emission) System Click here.

MONITOR DESCRIPTION

The 2 monitors, key-off and purge flow, are used to detect malfunctions relating to DTC P0441. The key-off monitor is initiated by the ECM internal timer, known as the soak timer, 5 hours* after the power switch is turned off. The purge flow monitor runs while the engine is running.


  1. KEY-OFF MONITOR

    5 hours* after the power switch is turned off, the electric leak detection pump creates negative pressure (vacuum) in the EVAP (Evaporative Emission) system. The ECM monitors for leaks and actuator malfunctions based on the EVAP pressure.

    Tech Tips

    *: If the engine coolant temperature is not less than 35°C (95°F) 5 hours after the power switch is turned off, the monitor check starts 2 hours later. If it is still not less than 35°C (95°F) 7 hours after the power switch is turned off, the monitor check starts 2.5 hours later.

    Sequence Operation Description Duration
    - ECM activation Activated by soak timer 5, 7 or 9.5 hours after power switch turned off. -
    A Atmospheric pressure measurement

    Vent valve is turned off (vent) and EVAP system pressure is measured by ECM in order to register atmospheric pressure.

    If pressure in EVAP system is not between 70 kPa(abs) and 110 kPa(abs) [525 mmHg(abs) and 825 mmHg(abs)], ECM cancels EVAP system monitor.

    		 60 seconds
    B First reference pressure measurement In order to determine reference pressure, leak detection pump creates negative pressure (vacuum) through reference orifice and then ECM checks if leak detection pump and vent valve operate normally. 360 seconds
    C EVAP system pressure measurement

    Vent valve is turned on (closed) to shut EVAP system.

    Negative pressure (vacuum) is created in EVAP system, and EVAP system pressure is then measured.

    Write down measured value as it will be used in leak check.

    If EVAP pressure does not stabilize within 15 minutes, ECM cancels EVAP system monitor.

    		 15 minutes*
    D Purge VSV monitor

    Purge VSV opened and then EVAP system pressure is measured by ECM.

    A large increase indicates normality.

    		 10 seconds
    E Second reference pressure measurement

    After second reference pressure measurement, leak check is performed by comparing first and second reference pressure measurements.

    If stabilized system pressure is higher than second reference pressure, ECM determines that EVAP system leaking.

    		 60 seconds
    - Final check Atmospheric pressure is measured and then monitoring result is recorded by ECM. -

    *: If only a small amount of fuel is in the fuel tank, it takes longer for the EVAP pressure to stabilize.

    A000RFPE27
    Text in Illustration
    *1 Operation A: Atmospheric Pressure Measurement *2 Operation B, E:
    *3 Purge VSV: OFF *4 Canister
    *5 Reference Orifice *6 Fuel Tank
    *7 Vent Valve: OFF (vent) *8 Canister Pump Module
    *9 Canister Pressure Sensor *10 Canister Filter
    *11 Leak Detection Pump: OFF *12 OFF
    *13 OFF (vent) *14 Reference Leak Pressure Measurement
    *15 ON *16 Reference Orifice (0.02 inch)
    *17 Operation C: EVAP System Pressure Measurement *18 ON (closed)
    *19 Atmospheric Pressure *20 Negative Pressure
    *21 OFF *22 ON
    *23 Operation D: Purge VSV Monitor *24 ON
    *25 ON (closed) *26 ON

    1. Purge VSV stuck open

      In operation C, the leak detection pump creates negative pressure (vacuum) in the EVAP (Evaporative Emission) system. The EVAP system pressure is then measured by the ECM using the canister pressure sensor. If the stabilized system pressure is higher than [second reference pressure x 0.2], the ECM interprets this as the purge VSV being stuck open. The ECM illuminates the MIL and stores the DTC (2 trip detection logic).

      A000S6YE02

    2. Purge VSV stuck closed

      In operation D, the canister pressure sensor measures the EVAP (Evaporative Emission) system pressure. The pressure measurement for the purge VSV monitor begins when the purge VSV is turned on (open) after the EVAP leak check. When the measured pressure indicates an increase of 0.3 kPa(gauge) [2.25 mmHg(gauge)] or more, the purge VSV is functioning normally. If the pressure does not increase, the ECM interprets this as the purge VSV being stuck closed, illuminates the MIL and sets the DTC (2 trip detection logic).

      A000R6YE02

  2. PURGE FLOW MONITOR

    The purge flow monitor consists of 2 monitors. The 1st monitor is conducted every time and the 2nd monitor is activated if necessary.

    A000RM1E93

Atmospheric pressure check:

In order to ensure reliable malfunction detection, the variation between the atmospheric pressures, before and after conduction of the purge flow monitor, is measured by the ECM.

MONITOR STRATEGY

Required Sensors/Components Purge VSV and canister pump module
Frequency of Operation Once per driving cycle

CONFIRMATION DRIVING PATTERN


  1. Connect the GTS to the DLC3.

  2. Turn the power switch on (IG) and turn the GTS on.

  3. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).

  4. Turn the power switch off and wait for at least 30 seconds.

  5. Turn the power switch on (IG) and turn the GTS on.

  6. Put the engine in inspection mode (maintenance mode) Click here.

  7. Start the engine and wait 15 minutes or more.

  8. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

  9. Read the pending DTCs.

    Tech Tips


    • If a pending DTC is output, the system is malfunctioning.

    • If a pending DTC is not output, perform the following procedure.

  10. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

  11. Input the DTC: P0441.

  12. Check the DTC judgment result.

    GTS Display Description
    NORMAL

    • DTC judgment completed

    • System normal
    ABNORMAL

    • DTC judgment completed

    • System abnormal
    INCOMPLETE

    • DTC judgment not completed

    • You should perform driving pattern after confirming DTC enabling conditions
    N/A

    • Unable to perform DTC judgment

    • Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

    Tech Tips


    • If the judgment result shows NORMAL, the system is normal.

    • If the judgment result shows ABNORMAL, the system has a malfunction.

    • If the judgment result shows INCOMPLETE or N/A, perform the following procedure.

    Note


    • The Evaporative System Check (Automatic Mode) consists of 6 steps performed automatically by the GTS. It takes a maximum of approximately 18 minutes.

    • Do not perform the Evaporative System Check when the fuel tank is more than 90% full because the cut-off valve may be closed, making the fuel tank leak check unavailable.

    • Do not run the engine during this operation.

    • When the temperature of the fuel is 35°C (95°F) or higher, a large amount of vapor forms and any check results become inaccurate. When performing the Evaporative System Check, keep the fuel temperature less than 35°C (95°F).

  13. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).

  14. Turn the power switch off and wait for at least 30 seconds.

  15. Turn the power switch on (IG) and turn the GTS on.

  16. Enter the following menus: Powertrain / Engine and ECT / Utility / Evaporative System Check / Automatic Mode.

  17. After the Evaporative System Check is completed, check for All Readiness by entering the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

  18. Input the DTC: P0441.

  19. Check the DTC judgment result.

    GTS Display Description
    NORMAL

    • DTC judgment completed

    • System normal
    ABNORMAL

    • DTC judgment completed

    • System abnormal
    INCOMPLETE

    • DTC judgment not completed

    • Perform driving pattern after confirming DTC enabling conditions
    N/A

    • Unable to perform DTC judgment

    • Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

    Tech Tips


    • If the judgment result shows NORMAL, the system is normal.

    • If the judgment result shows ABNORMAL, the system has a malfunction.

CAUTION / NOTICE / HINT

Refer to the EVAP System Click here.

PROCEDURE


  1. GO TO EVAP SYSTEM


    1. Refer to EVAP System Click here.


    NEXT

    END