Evaporative emission system vent control circuit malfunction
The ECM commanded the vent valve and did not see the electrical or pressure response it expected. This is a circuit and component fault rather than a leak measurement.
The vent control circuit reads outside its expected range during the monitor, or the valve does not respond to command.
Generic SAE definition. Manufacturers extend and sometimes override these, so the enhanced code on the vehicle in front of you may be narrower than what is written here.
This is the list every other P0446 page will give you. Read it, then read the part underneath it.
Every one of those 4 causes is now a decision somebody in the bay has to make, under a clock, on a car a customer wants back today.
We could mock one up. We’re not going to. A fabricated example of our own product’s output is exactly the kind of thing this page is criticizing. Verdicts appear here as the pilot produces them on real vehicles, with the evidence they actually stood on.
The pilot runs on your existing scan tool and your live repair orders. Bring us a car that's throwing this code.