P0441

1NZ-FXE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0441: Evaporative Emission Control System Incorrect Purge Flow

DTC P0441 - Evaporative Emission Control System Incorrect Purge Flow

DTC SUMMARY





DESCRIPTION
NOTE: In this vehicle's EVAP system, turning ON the vent valve does not seal off the EVAP system. To check for leaks in the EVAP system, disconnect the air inlet vent hose and apply pressure from the atmosphere side of the canister.

While the engine is running, if a predetermined condition (closed loop, etc.) is met, the purge VSV is opened by the ECM and the stored fuel vapors in the canister are purged to the intake manifold. The ECM changes the duty cycle ratio of the purge VSV to control purge flow volume.
The purge flow volume is also determined by the intake manifold pressure. Atmospheric pressure is allowed into the canister through the vent valve to ensure that the purge flow is maintained when the negative pressure (vacuum) is applied to the canister.

Key-off monitor

This monitor checks for Evaporative Emission (EVAP) system leaks and canister pump module malfunctions. The monitor starts 5 hours* after the power switch is turned OFF. More than 5 hours are required to allow the fuel to cool down to stabilize the Fuel Tank Pressure (FTP), thus making the EVAP system monitor more accurate.
The leak detection pump creates negative pressure (vacuum) in the EVAP system and the pressure is measured. Finally, the ECM monitors for leaks from the EVAP system and malfunctions in both the canister pump module and purge VSV, based on the EVAP pressure.
HINT: *: If the engine coolant temperature is not below 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 below 35°C (95°F) 7 hours after the power switch is turned OFF, the monitor check starts 2.5 hours later.





















MONITOR DESCRIPTION

1. Key-off monitor
5 hours* after the power 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 power 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 power switch is turned OFF, the monitor check starts 2.5 hours later.





*: 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 0.02 inch leak criterion x 0.15], the ECM interprets this as the purge Vacuum Switching Valve (VSV) being stuck open. The ECM illuminates the MIL and sets 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 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 (2.25 mmHg) 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).





3. Purge flow
While the engine is running, the purge VSV opens to purge the fuel vapor according to the engine condition. The ECM check the EVAP pressure when the purge VSV opens.
If the pressure dose not change, the ECM interprets this as a malfunction. The ECM illuminates the MIL and sets DTC (2 trip detection logic).

MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS

Purge Flow Monitor:





Purge VSV Stuck:





Key-off monitor sequence 1 to 8

1. Atmospheric pressure measurement





2. First reference pressure measurement





3. EVAP canister vent valve close stuck check





4. Vacuum introduction





5. EVAP canister purge valve close stuck check





6. Second reference pressure measurement





7. Leak check





8. Atmospheric pressure measurement





TYPICAL MALFUNCTION THRESHOLDS

"Saturated" indicates that the EVAP pressure change is less than 0.1 kPa (0.75 mmHg) in 30 seconds.

Purge Flow Monitor:





Key-off Monitor: Purge VSV stuck open





Key-off Monitor: Purge VSV stuck closed





MONITOR RESULT

Refer to CHECKING MONITOR STATUS Mode 6 Data.

WIRING DIAGRAM









INSPECTION PROCEDURE
NOTE: Techstream is required to conduct the following diagnostic troubleshooting procedure.
HINT:
- Using Techstream monitor results enables the EVAP system to be confirmed.
- Read freeze frame data using 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 be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air/fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.

PROCEDURE

1. CONFIRM DTC
(a) Turn the power switch OFF and wait for 10 seconds.
(b) Turn the power switch ON (IG).
(c) Turn the power switch OFF and wait for 10 seconds.
(d) Connect Techstream to the DLC3.
(e) Turn the power switch ON (IG).
(f) Enter the following menus: Powertrain / Engine and ECT / Trouble Code.
(g) Check if DTC P0446 is output.
NO -- PERFORM EVAPORATIVE SYSTEM CHECK
YES -- Continue to next step.

2. PERFORM EVAPORATIVE SYSTEM CHECK
(a) Note the freeze frame data and DTCs.
(b) Clear the DTCs DTC Check / Clear.
(c) Enter the following menus: Powertrain / Engine and ECT / Utility / Evaporative System Check / Automatic Mode.
(d) After the system check is finished, check for pending DTCs.
OK:
No DTC is present.
NG -- CHECK DTC
OK -- Continue to next step.

3. CHECK OPERATION FOR PURGE FLOW SWITCHING VALVE
(a) Enter the following menus: Powertrain / Engine and ECT / Active Test / Activate the VSV for Tank Bypass.
(b) Touch the purge flow switching valve (TANK BYPASS VSV) to feel the operating vibration.
OK:
The purge flow switching valve is operated by the Active Test.
NG -- CHECK HARNESS AND CONNECTOR (PURGE FLOW SWITCHING VALVE - ECM AND EFI M RELAY)
OK -- Continue to next step.

4. CHECK PURGE FLOW SWITCHING VALVE




(a) Turn the power switch OFF.
(b) Remove the purge flow switching valve.
(c) Reconnect the purge flow switching valve connector.
(d) Enter the following menus: Powertrain / Engine and ECT / Active Test / Activate the VSV for Tank Bypass.
(e) Check the airflow for the purge flow switching valve.
OK:
The purge flow switching valve operates normally.
OK -- REPLACE HOSE (PURGE FLOW SWITCHING VALVE AND FUEL TANK)
NG -- REPLACE PURGE FLOW SWITCHING VALVE
5. PERFORM EVAPORATIVE SYSTEM CHECK
(a) Enter the following menus: Powertrain / Engine and ECT / Utility / Evaporative System Check / Automatic Mode.
(b) After the system check is finished, check for pending DTCs.
OK:
DTCs are present.
NG -- CHECK FOR INTERMITTENT PROBLEMS
OK -- Continue to next step.

6. CHECK DTC
(a) Check the DTCs that were present in the EVAP system check.
OK:
P043E, P043F, P2401, P2402 and P2419 are present.
NG -- CHECK DTC
OK -- Continue to next step.

7. CHECK VENT VALVE CLOSE STUCK
(a) Allow the engine to idle.
(b) Enter the following menus: Powertrain / Engine and ECT / Active Test / Activate the VSV for EVAP Control.
(c) Turn the EVAP VSV ON (purge VSV open) and check the VAPOR PRESS (EVAP pressure) for 10 seconds.
OK:
EVAP pressure is higher than 755 mmHg.
NG -- CHECK FOR VENT HOSE CLOG
OK -- Continue to next step.

8. CHECK LEAK DETECTION PUMP OPERATION
(a) Turn the power switch OFF.
(b) Turn the power switch ON (IG).
(c) Enter the following menus: Powertrain / Engine and ECT / Active Test / Activate the Vacuum Pump.
(d) Touch the pump module to feel the operating vibration.
OK:
The leak detection pump is operated by the Active Test.
NG -- CHECK HARNESS AND CONNECTOR (CANISTER PUMP MODULE - ECM)
OK -- Continue to next step.

9. CHECK TRAP CANISTER




(a) Disconnect the vent hose from the pump module.
(b) Check that no moisture is in the pump module or the vent hose.
OK:
No moisture.
NG -- CHECK FOR VENT HOSE DAMAGE
OK -- REPLACE TRAP CANISTER WITH PUMP MODULE
10. CHECK DTC
(a) Check the DTCs that were present in the EVAP system check.
OK:
P0441, P0455 and/or P0456 are present.
NG -- CHECK DTC
OK -- Continue to next step.

11. CHECK INSTALLATION CONDITION OF FUEL CAP
(a) Remove the fuel cap.
(b) Reinstall the fuel cap.
(c) Clear the DTCs DTC Check / Clear.
(d) Enter the following menus: Powertrain / Engine and ECT / Utility / Evaporative System Check / Automatic Mode.
(e) After the system check is finished, check for pending DTCs.
HINT: If no DTC is present, this indicates that the fuel cap is loosened.

OK:
No DTC is present.
OK -- REPAIR COMPLETED
NG -- Continue to next step.

12. LOCATE LEAK POINT
(a) Disconnect the vent hose (fresh air line) as shown in the illustration.




(b) Connect the pressure gauge and air pump as shown in the illustration.
(c) Pressurize the EVAP system until the pressure reaches 24 to 28 mmHg.
(d) Locate the leak point.
HINT: If the EVAP system has leakage, a whistling sound may be heard.

OK:
The leak point is found.
OK -- REPAIR OR REPLACE LEAK POINT
NG -- Continue to next step.

13. CHECK FUEL CAP
(a) Check that the fuel cap meets OEM specifications.
HINT: If an EVAP tester is available, perform the fuel cap test according to the tester's instructions.

OK:
Fuel cap meets OEM specifications.
NG -- REPLACE FUEL CAP
OK -- Continue to next step.

14. CHECK OPERATION FOR PURGE VSV
(a) Enter the following menus: Powertrain / Engine and ECT / Active Test / Activate the VSV for EVAP Control.
(b) Touch the purge VSV to feel the operating vibration.
OK:
The purge VSV (EVAP VSV) is operated by the Active Test.
NG -- CHECK HARNESS AND CONNECTOR (PURGE VSV - ECM)
OK -- Continue to next step.

15. CHECK INTAKE MANIFOLD PRESSURE




(a) Disconnect the purge VSV hose that is connected to the throttle body.
(b) Allow the engine to idle.
(c) Check that the hose has suction using your finger.
OK:
The hose has suction.
OK -- REPLACE PURGE VSV
NG -- REPLACE HOSE (PURGE VSV - THROTTLE BODY)
16. CHECK DTC
(a) Check the DTCs that were present in the EVAP system check.
OK:
P0451 is not present.
NG -- CHECK TRAP CANISTER
OK -- Continue to next step.

17. CHECK OPERATION OF VENT VALVE
(a) Enter the following menus: Powertrain / Engine and ECT / Active Test / Activate the VSV for Vent Valve.
(b) Touch the pump module to feel the operating vibration.
OK:
The vent valve is operated by the Active Test.
NG -- CHECK HARNESS AND CONNECTOR (CANISTER PUMP MODULE - ECM)
OK -- CHECK TRAP CANISTER
18. CHECK HARNESS AND CONNECTOR (PURGE FLOW SWITCHING VALVE - ECM AND EFI M RELAY)
(a) Check the harness and the connectors between the purge flow switching valve and the ECM.





(1) Disconnect the V8 purge flow switching valve connector.





(2) Disconnect the E7 ECM connector.
(3) Measure the resistance according to the value(s) in the table below.
Standard resistance (Check for open):






Standard resistance (Check for short):






(4) Reconnect the purge flow switching valve connector.
(5) Reconnect the ECM connector.
(b) Check the harness and the connectors between the purge flow switching valve and the EFI M relay.
(1) Disconnect the V8 purge flow switching valve connector.





(2) Remove the integration relay from the engine room relay block.
(3) Measure the resistance according to the value(s) in the table below.
Standard resistance (Check for open):






Standard resistance (Check for short):






(4) Reconnect the purge flow switching valve connector.
(5) Reinstall the integration relay.
OK -- REPLACE ECM
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
19. REPLACE PURGE FLOW SWITCHING VALVE
(a) Replace the purge flow switching valve Locations.
NEXT -- PERFORM EVAPORATIVE SYSTEM CHECK
20. CHECK FOR VENT HOSE CLOG
(a) Turn the power switch OFF.




(b) Disconnect the vent hose (fresh air line) as shown in the illustration.
(c) Allow the engine to idle.
(d) Enter the following menus: Powertrain / Engine and ECT / Active Test / Activate the VSV for EVAP Control.
(e) Turn the purge VSV (EVAP VSV) ON and check the EVAP pressure (VAPOR PRESS) for 10 seconds.
OK:
EVAP pressure is higher than 755 mmHg.
OK -- CHECK AND REPLACE VENT HOSE OR CANISTER FILTER
NG -- REPLACE TRAP CANISTER WITH PUMP MODULE
21. CHECK HARNESS AND CONNECTOR (CANISTER PUMP MODULE - ECM)




(a) Disconnect the V7 canister pump module connector.




(b) Disconnect the E7 ECM connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance (Check for open):






Standard resistance (Check for short):





(d) Reconnect the canister pump module connector.
(e) Reconnect the ECM connector.
OK -- REPLACE ECM
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
22. REPLACE TRAP CANISTER WITH PUMP MODULE
(a) Replace the trap canister with pump module Removal.
NEXT -- PERFORM EVAPORATIVE SYSTEM CHECK
23. CHECK FOR VENT HOSE DAMAGE
(a) Check for hose damage as shown in the illustration. If necessary, replace the vent hose.





NEXT -- REPLACE TRAP CANISTER WITH PUMP MODULE
24. REPAIR OR REPLACE LEAK POINT
NEXT -- PERFORM EVAPORATIVE SYSTEM CHECK
25. REPLACE FUEL CAP
NEXT -- PERFORM EVAPORATIVE SYSTEM CHECK
26. CHECK HARNESS AND CONNECTOR (PURGE VSV - ECM)




(a) Disconnect the V1 purge VSV connector.




(b) Disconnect the E5 ECM connector.
(c) Check the harness and the connectors between the ECM and the purge VSV connectors.
(1) Measure the resistance according to the value(s) in the table below.
Standard resistance (Check for open):






Standard resistance (Check for short):









(d) Remove the integration relay from the engine room relay block.
(e) Check the harness and connectors between the purge VSV connector and the EFI M relay.
(1) Measure the resistance according to the value(s) in the table below.
Standard resistance (Check for open):






Standard resistance (Check for short):





(f) Reconnect the purge VSV connector.
(g) Reconnect the ECM connector.
(h) Reinstall the integration relay.
OK -- REPLACE ECM
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
27. REPLACE HOSE (PURGE VSV - THROTTLE BODY)
NEXT -- PERFORM EVAPORATIVE SYSTEM CHECK
28. REPLACE PURGE VSV
(a) Replace the purge VSV Locations.
NEXT -- PERFORM EVAPORATIVE SYSTEM CHECK
29. CHECK HARNESS AND CONNECTOR (CANISTER PUMP MODULE - ECM)




(a) Disconnect the V7 canister pump module connector.




(b) Disconnect the E7 ECM connector.
(c) Check the harness and the connectors between the ECM and the canister connectors.
(1) Measure the resistance according to the value(s) in the table below.
Standard resistance (Check for open):






Standard resistance (Check for short):









(d) Remove the integration relay from the engine room relay block.
(e) Check the harness and connectors between the canister pump module connector and the EFI M relay.
(1) Measure the resistance according to the value(s) in the table below.
Standard resistance (Check for open):






Standard resistance (Check for short):





(f) Reconnect the canister pump module connector.
(g) Reconnect the ECM connector.
(h) Reinstall the integration relay.
OK -- REPLACE ECM
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
30. REPAIR OR REPLACE HARNESS OR CONNECTOR
NEXT -- PERFORM EVAPORATIVE SYSTEM CHECK
31. REPLACE ECM
(a) Replace the ECM Removal.
NEXT -- PERFORM EVAPORATIVE SYSTEM CHECK
32. CHECK AND REPLACE VENT HOSE OR CANISTER FILTER
NEXT -- PERFORM EVAPORATIVE SYSTEM CHECK
33. REPLACE HOSE (PURGE FLOW SWITCHING VALVE AND FUEL TANK)
NEXT -- Continue to next step.

34. PERFORM EVAPORATIVE SYSTEM CHECK
(a) Turn the power switch ON (IG).
(b) Enter the following menus: Powertrain / Engine and ECT / Utility / Evaporative System Check / Automatic Mode.
(c) After the system check is finished, check for pending DTCs.
OK:
No DTC is present.
NG -- CHECK DTC
OK -- Continue to next step.

35. PERFORM EVAP MONITOR DRIVE PATTERN
(a) Check that the following conditions are met:

- Fuel level is 1/8 to 7/8.
- Engine coolant temperature (ECT) is 4.4 to 35°C (40 to 95°F).
- Intake air temperature (IAT) is 4.4 to 35°C (40 to 95°F).
- Difference between ECT and IAT is less than 7°C (44°F).
(b) Enter the check mode. Enter the following menus: Powertrain / Engine and ECT / Utility / Check Mode.
(c) Allow the engine to idle until the ECT is 75°C (167°F).
(d) Drive the vehicle at 30 mph (48 km/h) or faster and maintain that speed for 60 seconds or more.
(e) Stop the vehicle. Do not turn the power switch OFF.
(f) Check that the EVAP monitor status is complete. Enter the following menus: Powertrain / Engine and ECT / Monitor / Evaporative System.
(g) If the EVAP monitor is incomplete, drive the vehicle at 30 mph (48 km/h) or faster and maintain that speed for 120 seconds or more. After that, recheck the EVAP monitor status.
(h) Check for pending DTCs.
OK:
No DTC is present.
NG -- PERFORM EVAPORATIVE SYSTEM CHECK
OK -- REPAIR COMPLETED