Unveiling the Causes and Solutions for P0446 Evaporative Emission System

I was popping a 446 after every 120-150 miles or so. Now at 300 and no codes so still with fingers crossed. I also wanted to add my mpg went up from 16 to the ... Problems/Service/Repairs - PO446 Error Code - I know that this code is an emissions venting problem that can be associated with the gas cap, ... After a little research...looks like maybe the gas cap not on correctly...hopefully it is that simple anyway...will try that tonight, but any other advice will be ... P0446 is a diagnostic trouble code (DTC) for "Evaporative Emission Control System Vent Control Circuit Malfunction". This can happen for multiple reasons. P0446 Explained - EVAP Emission Control System Vent Control Circuit Malfunction (Simple Fix) · Comments123. DTC P0446 Evaporative Emission Vent System Performance How to fix P0446 EVAP Vent system performance code on a GM or Chevy truck. I recently purchased a cherry 2003 Tacoma Double Cab 3.4/Auto 4wd TRD. When I bought the truck the check engine light was on and I was given a new-in-box ... P0446 is an EVAP system code, and P0506 has to do with the Throttle Actuator Control (electric gas pedal) system. Does the purge vent normally stay open? Is this code strictly a diagnostic failure? If yes to both, I won't worry about this. This code can be triggered by an actual vent valve malfunction but can also be triggered by a leaky gas cap. By leaky, I mean the seal is ...