Circuit Description
WARNING: This page is about a different car, the 2004 Toyota Corolla. However, it is still accessible from the selected car via links, so may be relevant.
The vapor pressure sensor, VSV for canister closed valve (CCV), 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.
DTCs P0441 and P0446 are recorded by the ECM when evaporative emissions leak from the components within the dotted line in Fig 1 below, or when there is malfunction in both VSV for EVAP and VSV for pressure switching valve, or in the vapor pressure sensor itself.
DTC DETECTION CONDITION
| DTC No. | DTC Detecting Condition | Trouble Area |
|---|---|---|
| P0441 | Pressure in charcoal canister and fuel tank does not drop during purge control (2 trip detection logic) |
|
| During purge cut-off, pressure is very low compared with atmospheric pressure (2 trip detection logic) | ||
| P0446 | No rising the fuel tank pressure when commanding the CCV open after an EVAP leak test | |
| No changing the fuel tank pressure when commanding the pressure switching valve for the check after the EVAP leak test | ||
| A high negative pressure (vacuum) does not occurs in the system when commanding the VSV for EVAP open with the CCV closed |
HINT:
Typical DTC output of each trouble part.
TROUBLE PART
| Trouble part | Typical DTC output ((1)) | |||||
| Small Leak | P0442 and/or P0456 ((2)) | |||||
| Medium Leak (ex: Vacuum hose loose) | P0442 | |||||
| Large Leak (ex: Fuel tank cap loose) | P0441 and P0442 and P0446 | |||||
| VSV for EVAP | Open Malfunction | P0441 | ||||
| Close Malfunction | P0441 and P0442 and P0446 | |||||
| VSV for CCV | Open Malfunction | P0441 and P0442 and P0446 | ||||
| Close Malfunction | P0446 | |||||
| VSV for Pressure Switching | Open Malfunction | P0446 | ||||
| Close Malfunction | P0441 and P0442 and P0446 | |||||
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