P0441

2GR-FSE ENGINE CONTROL: SFI SYSTEM: P0441: Evaporative Emission Control System Incorrect Purge Flow
P0441 - Evaporative Emission Control System Incorrect Purge Flow

DTC SUMMARY





DESCRIPTION

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

HINT
Unit expressions

- (kPa-a [mmHg-a]) denotes absolute pressure.
- (kPa-g [mmHg-g]) denotes gauge pressure (relative pressure).
- On the Techstream, convert unit of measurement according to the inspection procedure.

INSPECTION PROCEDURE

Refer to the EVAP System EVAP System.

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*1 after the engine switch is turned off. The purge flow monitor runs while the engine is running.

1. KEY-OFF MONITOR

5 hours*1 after the engine 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
*1: If the engine coolant temperature is not below 35°C (95°F) 5 hours after the engine 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 engine switch is turned off, the monitor check starts 2.5 hours later.





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





Text in Illustration





(a) 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 leak pressure standard x 0.2], the ECM interprets this as the purge VSV being stuck open. The ECM illuminates the MIL and sets the DTC (2 trip detection logic).





(b) Purge VSV stuck closed

In operation D, the canister pressure sensor measures the EVAP (Evaporative Emission) system pressure. The pressure measurement for 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-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 sets the DTC (2 trip detection logic).





2. PURGE FLOW MONITOR

The purge flow monitor consists of the 2 step 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 0.5 kPa-g (3.75 mmHg-g), the ECM interprets this as the purge VSV being stuck closed, and illuminates the MIL and sets 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





TYPICAL ENABLING CONDITIONS

Key-off Monitor





1. Key-off monitor sequence 1 to 8

1. Atmospheric Pressure Measurement





2. First Reference Pressure Measurement





3. EVAP Canister Vent Valve Stuck Closed Check





4. Vacuum Introduction





5. EVAP Canister Purge Valve Stuck Closed Check





6. Second Reference Pressure Measurement





7. Leak Check





8. Atmospheric Pressure Measurement





Purge Flow Monitor





TYPICAL MALFUNCTION THRESHOLDS

Purge VSV Stuck Open





Purge VSV Stuck Closed





Purge Flow:





CONFIRMATION DRIVING PATTERN





1. Connect the Techstream to the DLC3.

2. Turn the engine switch on (IG) and turn the Techstream on.

3. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure) Reading and Clearing Diagnostic Trouble Codes.

4. Turn the engine switch off and wait for 30 seconds.

5. Turn the engine switch on (IG) and turn the Techstream on [A].

6. Start the engine and wait 15 minutes or more [B].

7. Enter the following menus: Powertrain / Engine / Utility / All readiness.

8. Input the DTC: P0441.

9. Check the DTC judgment result [C].





NOTICE:
- The Evaporative System Check (Automatic Mode) consists of 5 steps performed automatically by the Techstream. 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 more, 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).

10. Turn the engine switch on (IG) and turn the Techstream on.

11. Clear the DTCs (even if no DTCs are stored, perform the clear the DTC operation) Reading and Clearing Diagnostic Trouble Codes.

12. Turn the engine switch off and wait for 30 seconds.

13. Turn the engine switch on (IG) and turn the Techstream on.

14. Enter the following menus: Powertrain / Engine / Utility / Evaporative System Check / Automatic Mode [D].

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

16. Input the DTC: P0441.

17. Check the DTC judgment result [E].





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

18. If the test result is UNKNOWN, enter the following menus: Powertrain / Engine / Trouble Codes / Pending.

19. Read Pending DTCs.

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

20. If the test result is INCOMPLETE or UNKNOWN and no pending DTC is output, perform a universal trip and check for permanent DTCs Reading and Clearing Diagnostic Trouble Codes.

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

MONITOR RESULT

Refer to Checking Monitor Status Mode 6 Data.