P0441
2AZ-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.
HINT
Unit expression
- (kPa-a [mmHg-a]) denotes absolute pressure.
- (kPa-g [mmHg-g]) denotes gauge pressure (relative pressure).
- On the Techstream, convert the unit of measurement according to the inspection procedure.
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 hybrid vehicle control ECU 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 hybrid vehicle control ECU 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 hybrid vehicle control ECU using the canister pressure sensor. If the stabilized system pressure is higher than [second 0.02 inch leak pressure standard x 0.2], the hybrid vehicle control ECU interprets this as the purge VSV being stuck open. The hybrid vehicle control ECU 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.
(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 hybrid vehicle control ECU interprets this as the purge VSV being stuck closed. The hybrid vehicle control ECU 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 hybrid vehicle control ECU monitors the purge flow by measuring the EVAP pressure change. If negative pressure is not created, the hybrid vehicle control ECU 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 hybrid vehicle control ECU 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 hybrid vehicle control ECU.
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
MONITOR RESULT
Refer to Checking Monitor Status Mode 6 Data.
CONFIRMATION DRIVING PATTERN
- Connect the Techstream to the DLC3.
- Turn the power switch on (IG) and turn the Techstream on.
- Clear the DTCs DTC Check / Clear.
- Turn the power switch off and wait for at least 30 seconds.
- Turn the power switch on (IG) and turn the Techstream on [A].
- Put the engine in inspection mode Component Tests and General Diagnostics.
- Start the engine and wait 15 minutes or more [B].
- Enter the following menus: Powertrain / Engine and ECT / Trouble Codes/ Pending.
- Read the pending DTC [C].
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.
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).
- Turn the power switch on (IG) and turn the Techstream on.
- Clear the DTCs DTC Check / Clear.
- Turn the power switch off and wait for 30 seconds.
- Turn the power switch on (IG) and turn the Techstream on.
- Enter the following menus: Powertrain / Engine and ECT / Utility / Evaporative System Check / Automatic Mode [D].
- After the "Evaporative System Check" is completed, check for All Readiness by entering the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
- Input the DTC: P0441.
- Check the DTC judgment result [E].
HINT
If the judgment result shows ABNORMAL, the system has a malfunction.
INSPECTION PROCEDURE
Refer to the EVAP System EVAP System.