Toyota Venza manuals

Toyota Venza: Evaporative Emission Control System Incorrect Purge Flow (P0441)

Toyota Venza Service Manual / 1ar-fe Engine Control / Sfi System / Evaporative Emission Control System Incorrect Purge Flow (P0441)

DTC SUMMARY

DTC No.

Monitoring Item

Malfunction 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 x 0.2], ECM determines that purge VSV stuck open.

  • Purge VSV
  • Connector/wire harness (purge VSV - ECM)
  • ECM
  • Canister pump module
  • Leak from EVAP system

While ignition switch off

2 trip

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 check.

If pressure does not return to near atmospheric pressure, ECM determines that purge VSV 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 ignition switch off

2 trip

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 0.15 kPa(gauge) [1.125 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 description can be found in EVAP (Evaporative Emission) System (See page ).


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 ignition switch is turned off. The purge flow monitor runs while the engine is running.

  1. KEY-OFF MONITOR

    5 hours* after the ignition 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.

    HINT:

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

    Text in Illustration

    *1

    Purge VSV: Off (Closed)

    *2

    Purge VSV: On (Open)

    *3

    Vent Valve: Off (Vent)

    *4

    Vent Valve: On (Closed)

    *5

    Leak Detection Pump: Off

    *6

    Leak Detection Pump: On

    *7

    Reference Orifice (0.02 inch)

    *8

    Canister Pressure Sensor

    *9

    Canister

    *10

    Fuel Tank

    *11

    Canister Pump Module

    *12

    Canister Filter

    *a

    Operation A:

    Atmospheric Pressure Measurement

    *b

    Operation B, E:

    Reference Pressure Measurement

    *c

    Operation C:

    EVAP System Pressure Measurement

    *d

    Operation D:

    Purge VSV Monitor

    *e

    Atmospheric Pressure

    *f

    Negative Pressure

    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).


    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 higher, 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 stores the DTC (2 trip detection logic).


  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.


  • The 1st monitor

    While the engine is running and the purge VSV is on (open), the ECM monitors the purge flow by measuring the EVAP pressure change. If negative pressure is not created, the ECM begins the 2nd monitor.

  • The 2nd monitor

    The vent valve is turned on (closed) and the EVAP pressure is then measured. If the variation in the pressure is less than 0.15 kPa(gauge) [1.125 mmHg(gauge)], the ECM interprets this as the purge VSV being stuck closed, illuminates the MIL and stores DTC P0441 (2 trip detection logic).

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 (Main)

Purge VSV

Canister pump module

Required Sensors/Components (Related)

-

Frequency of Operation

Once per driving cycle

Duration

Within 20 minutes: Purge VSV stuck open/close

Within 30 seconds: Purge flow

MIL Operation

2 driving cycles

Sequence of Operation

None

TYPICAL ENABLING CONDITIONS

All

Monitor runs whenever the following DTCs are not stored

None

Key-off Monitor

Atmospheric pressure

70 kPa(abs) [525 mmHg(abs)] or higher, and less than 110 kPa(abs) [825 mmHg(abs)]

Battery voltage

10.5 V or higher

Vehicle speed

Less than 4 km/h (2.5 mph)

Ignition switch

Off

Time after key-off

5, 7 or 9.5 hours

Canister pressure sensor malfunction

Not detected

Purge VSV

Not operated by scan tool

Vent valve

Not operated by scan tool

Leak detection pump

Not operated by scan tool

Both of following conditions met before key-off

Conditions 1 and 2

1. Duration that vehicle is driven

5 minutes or more

2. EVAP purge operation

Performed

Engine coolant temperature

4.4°C (40°F) or higher, and less than 35°C (95°F)

Intake air temperature

4.4°C (40°F) or higher, and less than 35°C (95°F)

Purge Flow Monitor

Engine

Running

Engine coolant temperature

4.4°C (40°F) or higher

Intake air temperature

4.4°C (40°F) or higher

Canister pressure sensor malfunction

Not detected

Purge VSV

Not operated by scan tool

EVAP system check

Not operated by scan tool

Battery voltage

10 V or higher

Purge duty-cycle

8% or higher

TYPICAL MALFUNCTION THRESHOLDS

Purge VSV Stuck Open

EVAP pressure when vacuum introduction is complete

Higher than [reference pressure x 0.2]

Purge VSV Stuck Closed

EVAP pressure change after purge VSV is open

Less than 0.3 kPa(gauge) [2.25 mmHg(gauge)]

Purge Flow

Both of the following conditions are met:

Conditions 1 and 2

1. EVAP pressure change when purge flow is started

Less than 0.1 kPa(gauge) [0.75 mmHg(gauge)]

2. EVAP pressure change during purge operation when vent valve closed

Less than 0.15 kPa(gauge) [1.125 mmHg(gauge)]

MONITOR RESULT

Refer to Checking Monitor Status (See page
).

CONFIRMATION DRIVING PATTERN

  1. Connect the Techstream to the DLC3.
  2. Turn the ignition switch to ON and turn the Techstream on.
  3. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure) (See page ).

  4. Turn the ignition switch off and wait for at least 30 seconds.
  5. Turn the ignition switch to ON and turn the Techstream on.
  6. Start the engine and wait 15 minutes or more.
  7. Enter the following menus: Powertrain / Engine / Trouble Codes.
  8. Read pending DTCs.

    HINT:

    • If a pending DTC is output, the system is malfunctioning.
    • If a pending DTC is not output, perform the following procedure.
  9. Enter the following menus: Powertrain / Engine / Utility / All Readiness.
  10. Input the DTC: P0441.
  11. Check the DTC judgment result.

    Techstream 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

    HINT:

    • 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.

    NOTICE:

    • The Evaporative System Check (Automatic Mode) consists of 6 steps performed automatically by the Techstream. It takes a maximum of approximately 24 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 below 35°C (95°F).
  12. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure) (See page ).

  13. Turn the ignition switch off and wait for at least 30 seconds.
  14. Turn the ignition switch to ON.
  15. Turn the Techstream on.
  16. Enter the following menus: Powertrain / Engine / 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 / Utility / All Readiness.
  18. Input the DTC: P0441.
  19. Check the DTC judgment result [E].

    Techstream 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

    HINT:

    • If the judgment result shows NORMAL, the system is normal.
    • If the judgment result shows ABNORMAL, the system has a malfunction.
  20. If the judgment result is INCOMPLETE or N/A and no pending DTC is output, perform a universal trip and check for permanent DTCs (See page ).

    HINT:

    • If a permanent DTC is output, the system is malfunctioning.
    • If no permanent DTC is output, the system is normal.

PROCEDURE

1.

REFER TO THE EVAP SYSTEM

Refer to EVAP System (See page ).



NEXT

END

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