DTC P0446: Evaporative Emission System Vent Control Circuit

WARNING: This page does not describe the selected car, but rather 33 other vehicles, including the 2010 Mercury Mountaineer, 2010 Mercury Milan, 2010 Mercury Mariner, 2010 Mercury Grand Marquis, and 2010 Lincoln Town Car. However, it is still accessible from the selected car via links, so may be relevant.

DTC P0446: EVAPORATIVE EMISSION SYSTEM VENT CONTROL CIRCUIT

Description:	Monitors the canister vent (CV) solenoid circuit for an electrical failure. The test fails when the signal moves outside the minimum or maximum allowable calibrated parameters for a specified canister vent duty cycle by powertrain control module (PCM) command.
Possible Causes:	VPWR circuit open KAPWR circuit open (vehicles equipped with engine off natural vacuum (EONV) EVAP leak check monitor) CV solenoid circuit short to ground Damaged CV solenoid CV solenoid circuit open CV solenoid circuit short to voltage CV solenoid circuit short to KAPWR (vehicles equipped with engine off natural vacuum (EONV) EVAP leak check monitor) Damaged PCM
Diagnostic Aids:	To verify normal functioning, monitor the EVAP canister vent solenoid signal PID EVAPCV and the signal voltage (PCM control side). With the valve open, EVAPCV indicates 0% duty cycle and a voltage approximately equal to battery voltage. When the valve is commanded fully closed, EVAPCV indicates 100% duty cycle, and a minimum voltage drop of 4 volts is normal. Output test mode (OTM) may be used to switch output on/off to verify function.
Application	Key On Engine Off	Key On Engine Running	Continuous Memory
All	GO to PINPOINT TEST HX .