P0446

P0446 - EVAP Emission Control System Vent Control Malfunction

CIRCUIT DESCRIPTION

DTC Detecting Condition:

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. 1pressure switching valve, or in the vapor pressure sensor itself.

Wiring Diagram:

INSPECTION PROCEDURE

HINT:
- If DTC P0441, P0446, P0450 or P0451 is output after DTC P0440,first troubleshoot DTC P0441, P0446, P0450 or P0451. If no malfunction is detected, troubleshoot DTC P0440 next.
- Read freeze frame data using TOYOTA hand-held tester or OBD II scan tool. 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 VSV for EVAP, charcoal canister and vapor pressure sensor.

Steps 1 - 2:

Steps 3 - 7:

Steps 8 - 11:

Steps 12 - 13:

Steps 14 - 16:

Steps 17 - 19:

Steps 20 - 21:

Steps 22 - 24:

TOYOTA hand-held tester

Steps 1 - 4:

Steps 5 - 8:

Steps 9 - 11:

Steps 12 - 14:

Steps 15 - 17:

OBD II scan tool (excluding TOYOTA hand-held tester)