Toyota Tundra Service Manual: Evaporative Emission Control System Incorrect Purge Flow (P0441)

Toyota Tundra Service Manual / Engine, Hybrid System / 1ur-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 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 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
  • Connector/wire harness (Purge VSV - ECM)
  • ECM
  • Canister pump module
  • 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 0.4 kPa-g (3.0 mmHg-g) when vent valve turned ON (closed)
  • Atmospheric pressure change before and after purge flow monitor less than 0.1 kPa-g (0.75 mmHg-g)
  • Purge VSV
  • Connector/wire harness (Purge VSV - ECM)
  • Leak from EVAP line (Purge VSV - Intake manifold)
  • ECM

While engine running

2 trip

DESCRIPTION

The description can be found in the EVAP (Evaporative Emission) system (See page ).

MONITOR DESCRIPTION

The two 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 leak detection pump creates negative pressure (vacuum) in the EVAP 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 turned OFF (vent) and EVAP system pressure measured by ECM in order to register atmospheric pressure.

    If pressure in EVAP system not between 70 kPa-a and 110 kPa-a (525 mmHg-a and 825 mmHg-a), 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 turned ON (closed) to shut EVAP system.

    Negative pressure (vacuum) created in EVAP system, and EVAP system pressure 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 measured by ECM.

    Large increase indicates normality.

    10 seconds

    E

    Second reference pressure measurement

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

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

    60 seconds

    -

    Final check

    Atmospheric pressure measured and then monitoring result recorded by ECM.

    -

    HINT:

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

    1. Purge VSV stuck open

      In operation C, the leak detection pump creates negative pressure (vacuum) in the EVAP 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 (Vacuum Switching Valve) 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 system pressure. The pressure measurement for the purge VSV monitor is begun when the purge VSV is turned ON (open) after the EVAP leak check. When the measured pressure indicates an increase of 0.3 kPa-g (2.25 mmHg-g) 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. The ECM illuminates the MIL and stores the DTC (2 trip detection logic).

  2. PURGE FLOW MONITOR

    The purge flow monitor consists of two 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 0.4 kPa-g (3.0 mmHg-g), the ECM interprets this as the purge VSV being stuck closed, and illuminates the MIL and stores DTC P0441 (2 trip detection logic).

Atmospheric pressure check:

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

OBD II MONITOR SPECIFICATIONS

1. Key-off Monitor

Monitor Strategy

Required Sensors/Components

Purge VSV and canister pump module

Frequency of Operation

Once per driving cycle

Duration

Within 20 minutes (varies with amount of fuel in tank)

MIL Operation

2 driving cycles

Sequence of Operation

None

Typical Enabling Condition

Monitor runs whenever following DTCs not stored

P0452, P0453 (EVAP system)

EVAP key-off monitor runs when all of following conditions met

-

Atmospheric pressure

70 to 110 kPa-a (525 to 825 mmHg-a)

Battery voltage

10.5 V or more

Vehicle speed

Below 4 km/h (2.5 mph)

Ignition switch

Off

Time after key off

5 or 7 or 9.5 hours

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 driven

5 minutes or more

2. EVAP purge operation

Performed

ECT

4.4 to 35°C (40 to 95°F)

IAT

4.4 to 35°C (40 to 95°F)

Typical Malfunction Threshold

Purge VSV stuck open:

-

EVAP pressure when vacuum introduction complete

Reference pressure x 0.2 or higher

Purge VSV stuck closed:

-

EVAP pressure change after purge VSV ON (open)

Less than 0.3 kPa-g (2.25 mmHg-g)

OBD II MONITOR SPECIFICATIONS

1. Purge Flow Monitor

Monitor Strategy

Required Sensors/Components

Purge VSV and canister pump module

Frequency of Operation

Once per driving cycle

Duration

Less than 30 sec.

MIL Operation

2 driving cycles

Sequence of Operation

None

Typical Enabling Condition

Monitor runs whenever following DTCs not present

P0452, P0453 (EVAP system)

Engine

Running

ECT

4.4°C (40°F) or more

IAT

4.4°C (40°F) or more

Purge VSV

Not operated by scan tool

EVAP system check

Not operated by scan tool

Atmospheric pressure

70 to 111 kPa (525 to 833 mmHg)

Battery voltage

10 V or more

Purge duty cycle

8% or more

Typical Malfunction Threshold

Both of following conditions met

Conditions 1 and 2

1. EVAP pressure change when purge operation started

Less than 0.1 kPa-g (0.75 mmHg-g)

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

Less than 0.4 kPa-g (3.0 mmHg-g)

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 operation).
  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 [A].
  6. Start the engine and wait 15 minutes or more [B].
  7. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes [C].
  8. Read the 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 and ECT / Utility / All Readiness.
  10. Input the DTC: P0441.
  11. Check the DTC judgment result.

    Tester 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

    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 operation).
  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 [D].
  16. Enter the following menus: Powertrain / Engine and ECT / Utility / Evaporative System Check / Automatic Mode.
  17. After the "Evaporative System Check" is completed, check 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 [E].

    Tester 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 ABNORMAL, the system has a malfunction.

  20. If the test 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.

CAUTION / NOTICE / HINT

HINT:

Read freeze frame data using the Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.

PROCEDURE

1.

CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO P0441)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

(e) Read the DTCs.

Result

Proceed to

DTC P0441 is output

A

DTC P0441 and other DTCs are output

B

HINT:

If any DTCs other than P0441 are output, perform troubleshooting for those DTCs first.

A

GO TO EVAP SYSTEM

B

GO TO DTC CHART

    Catalyst System Efficiency Below Threshold (Bank 1) (P0420,P0430)

    Evaporative Emission Control System Pressure Sensor Range / Performance (P0451-P0453)

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