Symptoms

- Engine Light ON (or Service Engine Soon Warning Light) - Possible a noticeable fuel odor caused by the release of fuel vapors

Possible Causes

- Missing Fuel cap - Incorrect fuel filler cap used - Fuel filler cap remains open or fails to close - Foreign matter caught in fuel filler cap - Incorrect fuel tank vacuum relief valve - Leak is in line between intake m

When Detected

- Pressure in charcoal canister and fuel tank does not drop during purge control (2 trip detection logic) - During purge cut off, negative pressure incoming in the charcoal canister and fuel tank will not stop. (2 trip detection logic)

Description

The vapor pressure sensor, Voltage Solenoide Valve (VSV) for EVAP, Voltage Solenoide Valve (VSV) for canister closed valve (CCV) and Valve Solenoide Valve (VSV) for 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. Diagnostic Trouble Code (DTC) P0441 is recorded by the ECM when there is a malfunction in either the VSV for EVAP, the VSV for pressure switching valve, or in the vapor pressure sensor itself, or when evaporative emissions leak from the components within the dotted line in Fig. 1 below. 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 EVAP. 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. Source: Toyota