SFI SYSTEM, Diagnostic DTC:P0441

DTC SUMMARY

DESCRIPTION

The 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.

   

   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	No. 1 Canister
   *11	No. 2 Canister	*12	Canister Pump Module
   *13	Canister Filter	*14	Fuel Tank
   *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 0.5 kPa(gauge) [3.751 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

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

MONITOR RESULT

Refer to EVAP system Click here.

CONFIRMATION DRIVING PATTERN

1. Connect the Techstream to the DLC3.

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

    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

    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 Techstream. It takes a maximum of approximately 24 minutes.

    • Do not perform the Evaporative System Check when the fuel tank is higher 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).

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 Techstream 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.

    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

    Tech Tips

    • 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 Click here.

    Tech Tips

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

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

INSPECTION PROCEDURE

PROCEDURE

1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0441)

   1. Connect the Techstream to the DLC3.

   2. Turn the power switch on (IG).

   3. Turn the Techstream on.

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

   5. Read the DTC.

      Result

      Result	Proceed to
      DTC P0441 is output	A
      DTC P0441 and other DTCs are output	B

      Tech Tips

      If any DTCs other than DTC P0441 are output, troubleshoot those DTCs first.

   B

   GO TO DTC CHART Click here

   A

2. PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE EGR STEP POSITION)

   1. Connect the Techstream to the DLC3.

   2. Turn the power switch on (IG).

   3. Turn the Techstream on.

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

   5. Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher.

      Tech Tips

      The A/C switch and all accessory switches should be off.

   6. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the EGR Step Position / Primary / Throttle Idle Position and MAP.

   7. Confirm that the Throttle Idle Position is ON and check the engine idling condition and MAP values in the Data List while performing the Active Test.

      Tech Tips

      • Do not leave the EGR valve open for 10 seconds or more during the Active Test.

      • Be sure to return the EGR valve to step 0 when the Active Test is completed.

      • Do not open the EGR valve 30 steps or more during the Active Test.

      OK
      MAP and idling condition change in response to EGR step position when Throttle Idle Position is ON in Data List.

      Standard
      - EGR Step Position (Active Test) 0 Steps 0 to 30 Steps Idling condition (Throttle Idle Position: ON) Steady idling Idling changes from steady to rough idling or engine stalls MAP (Data List) MAP value is 20 to 40 kPa(abs) [150 to 300 mmHg(abs)] (EGR valve is fully closed) MAP value is at least +10 kPa (75 mmHg) higher than when EGR valve is fully closed

      Tech Tips

      During Active Test, if the idling condition does not change in response to EGR step position, then there is probably a malfunction in the EGR valve.

      Result

      Result	Proceed to
      NG	A
      OK	B

   B

   GO TO EVAP SYSTEM Click here

   A

3. INSPECT EGR VALVE ASSEMBLY

   1. Remove the EGR valve assembly Click here.

   2. Check if the EGR valve is stuck open.

      OK
      EGR valve is tightly closed.

      Tech Tips

      Perform "Inspection After Repair" after replacing the EGR valve assembly Click here.

   NG

   REPLACE EGR VALVE ASSEMBLY Click here

   OK

   GO TO EVAP SYSTEM Click here