P0441
2ZR-FXE 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.
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 power switch is turned off. The purge flow monitor runs while the engine is running.
1. KEY-OFF MONITOR
5 hours*1 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.
HINT
*1: 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.
*2: If only a small amount of fuel is in the fuel tank, it takes longer for the EVAP pressure to stabilize.
(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 0.02 inch 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).
HINT
*: DTC P0441 may be stored if the hose between the purge VSV and canister is disconnected during evaporative emission control system operation.
(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 (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. 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 below 0.5 kPa (gauge) [3.75 mmHg (gauge)], 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
All
Key-off Monitor
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 power 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 power switch off and wait for 30 seconds.
5. Turn the power switch on (IG) and turn the Techstream on.
6. Put the engine in inspection mode (maintenance mode) Component Tests and General Diagnostics.
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.
HINT
- 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.
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 UNKNOWN, perform the following procedure.
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 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 operation) Reading and Clearing Diagnostic Trouble Codes.
14. Turn the power switch off and wait for 30 seconds.
15. Turn the power switch on (IG).
16. Turn the Techstream on.
17. Enter the following menus: Powertrain / Engine and ECT / Utility / Evaporative System Check / Automatic Mode.
18. After the Evaporative System is completed, check for All Readiness by entering the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
19. Input the DTC: P0441.
20. Check the DTC judgment result.
HINT
- If the judgment result shows NORMAL, the system is normal.
- If the judgment result shows ABNORMAL, the system has a malfunction.
21. If the judgment 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 EVAP System EVAP System.
INSPECTION PROCEDURE
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 DTC P0441)
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Turn the Techstream on.
(d) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
(e) Read the DTC.
Result
B -- GO TO DTC CHART SFI System
A -- Continue to next step.
2. PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE EGR STEP POSITION)
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Turn the Techstream on.
(d) Put the engine in inspection mode (maintenance mode) Component Tests and General Diagnostics.
(e) Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher.
HINT
The A/C switch and all accessory switches should be off.
(f) Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the EGR Step Position / Data List / Primary / Throttle Idle Position and MAP.
(g) 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.
HINT
- 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:
HINT
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
B -- GO TO EVAP SYSTEM EVAP System
A -- Continue to next step.
3. INSPECT EGR VALVE ASSEMBLY
(a) Remove the EGR valve assembly Removal.
(b) Check if the EGR valve is stuck open.
OK:
EGR valve is tightly closed.
NG -- REPLACE EGR VALVE ASSEMBLY Removal
OK -- GO TO EVAP SYSTEM EVAP System