DTC P0441 Evaporative Emission Control System Incorrect Purge Flow |
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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. |
| 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. |
| While ignition switch off | 2 trip | |
Purge flow | While engine running, following conditions successively met:
|
| While engine running | 2 trip |
DESCRIPTION
The description can be found in the EVAP (Evaporative Emission) System (Click here).INSPECTION PROCEDURE
Refer to the EVAP System (Click here).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.- 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 111 kPa-a (525 mmHg-a and 833 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. 60 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.
- 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). - 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). - 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 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).
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
Required Sensors/Components | Purge VSV and canister pump module |
Frequency of Operation | Once per driving cycle |
Duration | Within 20 minutes: Purge VSV stuck open/close Within 10 minutes: Purge flow |
MIL Operation | 2 driving cycles |
Sequence of Operation | None |
TYPICAL ENABLING CONDITIONS
Monitor runs whenever following DTCs not stored | None |
Atmospheric pressure | 70 to 111 kPa-a (525 to 833 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 |
Canister pressure sensor malfunction | Not detected |
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) |
Monitor runs whenever following DTCs not stored | None |
Engine | Running |
ECT | 4.4°C (40°F) or more |
IAT | 4.4°C (40°F) or more |
Canister pressure sensor malfunction | Not detected |
Purge VSV | Not operated by scan tool |
EVAP system check | Not operated by scan tool |
Atmospheric pressure | 70 to 111 kPa-a (525 to 833 mmHg-a) |
Battery voltage | 10 V or more |
Purge duty cycle | 8% or more |
TYPICAL MALFUNCTION THRESHOLDS
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) |
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 mmHg-g) |
MONITOR RESULT
Refer to CHECKING MONITOR STATUS (Click here).CONFIRMATION DRIVING PATTERN
- Connect the Techstream to the DLC3.
- Turn the ignition switch to ON and turn the Techstream on.
- Clear the DTCs (even if no DTCs are stored, perform the clear DTC operation).
- Turn the ignition switch off and wait for at least 30 seconds.
- Turn the ignition switch to ON and turn the Techstream on [A].
- Start the engine and wait 15 minutes or more [B].
- Enter the following menus: Powertrain / Engine and ECT / Trouble Codes [C].
- Read the pending DTC.
- HINT:
- If a pending DTC is output, the system is malfunctioning.
- If a pending DTC is not output, perform the following procedure.
- Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
- Input the DTC: P0441.
- 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 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).
- DTC judgment completed
- Turn the ignition switch to ON and turn the Techstream on.
- Clear the DTCs (even if no DTCs are stored, perform the clear DTC operation).
- Turn the ignition switch off and wait for at least 30 seconds.
- Turn the ignition switch to ON
- Turn the Techstream on [D].
- Enter the following menus: Powertrain / Engine and ECT / Utility / Evaporative System Check / Automatic Mode.
- After the "Evaporative System Check" is completed, check All Readiness by entering the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
- Input the DTC: P0441.
- 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.
- DTC judgment completed
- If the test result is INCOMPLETE or N/A and no pending DTC is output, perform a universal trip and check for permanent DTCs (Click here).
- HINT:
- If a permanent DTC is output, the system is malfunctioning.
- If no permanent DTC is output, the system is normal.