P0441

DTC P0441 EVAPORATIVE EMISSION CONTROL SYSTEM INCORRECT PURGE FLOW

CIRCUIT DESCRIPTION

DTC Detecting Condition:

The vapor pressure sensor, The VSV for the canister closed valve (CCV) and the VSV or the pressure switching valve are used to detect abnormalities in the evaporative emission control system.
The ECM decides whether there is an abnormality in the evaporative emission control system, based on the vapor pressure sensor signal.
DTCs P0441 and P0446 are recorded by the ECM when the evaporative emissions leak from the components within the dotted line in Fig. 1, or when there is a malfunction in either the VSV for the EVAP, the VSV for the pressure switching valve, or in the vapor pressure sensor itself.

P0441
The ECM closes the CCV and opens the VSV for pressure switching valve causing vacuum to increase in the entire EVAP system.
The ECM continues to operate the VSV for EVAP until the vacuum is increased to a specified point at which time the ECM closes the VSV for EVAR
If the vacuum did not increase, or if the vacuum increased beyond the specified limit, the ECM judges the VSV for EVAP and related components to be faulty.

P0446
When the vapor pressure rises to a specified point, the ECM opens the VSV for CCV. Pressure will increase rapidly because of the air allowed into the system. No increase or an increase below specified rate of pressure increase indicates a restriction on the air inlet side.
The ECM closes the VSV for pressure switching valve. This action blocks air entering the fuel tank side of system. The pressure rise on the fuel tank side is no longer as great.
If there was no change in pressure, the ECM will conclude the VSV for pressure switching valve did not close.






HINT:
Typical DTC output of each trouble pan

Wiring Diagram:

INSPECTION PROCEDURE

HINT:
- It DTC P0441 (Purge Flow), P0446 (VSV for CCV or VSV for Pressure switching valve), P0451, P0452 or P0453 (Evaporative Pressure Sensor) is output with DTC P0442 or P0456, first troubleshoot DTC P0441, P0446, P0451, P0452 or P0453. If no malfunction is detected, troubleshoot DTC P0442 or P0456 next.
- Read freeze frame data using OBD II scan tool or hand-held tester. Because freeze frame records the engine conditions when the malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio was lean or rich, etc. at the time of the malfunction.
- When the ENGINE RUN TIME in the freeze frame data is less than 200 seconds, carefully check the vapor pressure sensor.

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Hand-Held Tester

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OBD II Scan Tool (Excluding Hand-held Tester)