EVAP system code, WTF!

I have an EVAP system code that I can't seem to fix and am looking for some other advice.

The car in question is a 2006 Mazda3, 161k. Car had the code when I bought it cheap, trying to get it fixed. Code is a P0446, which is a Evaporative Emission Control System Vent Control Circuit Malfunction. First, the gas cap was replaced with a known good cap, no change. Second, I replaced the Evap purge solenoid as it was easy and fairly cheap and seemed to be an occasional failure point on the forums. No change. Third, I replaced the EVAP charcoal canister (which involved dropping the rear subframe), and cleaned out the valve next to it which looked to be in good condition. No change. I've blown compressed air through the lines, I've looked at what I can see for leaks.

What am I missing?

My guess is to find a guy with a EVAP smoke machine.

Sounds like you might have to pay someone to for the use of an high end scanner that can cycle the vent, maybe a broken wire or a bad ECU.

Paul

Isn't there a recall out for this? Spiders nest inside the vent causes clogging.

Control circuit codes indicate an electrical fault, not a leak. They're all getting pretty good about that sort of thing. Either a corroded wire going to the vent solenoid or a bad solenoid, which is easy enough to check.

Knurled wrote: Control circuit codes indicate an electrical fault, not a leak. They're all getting pretty good about that sort of thing. Either a corroded wire going to the vent solenoid or a bad solenoid, which is easy enough to check.

+1.

The fault is vent control circuit manfunction. So either the valve is acting up, electrically, or the circuit is.

It's open or shorted, simple as that. Check to see that the valve is actually plugged in.

It's almost certainly going to be corroded wiring running to the vent valve on the canister.

Usually it's obvious enough that if you drop all the stuff around the vent valve and start feeling up the harness, you'll suddenly start squeezing crumbly ashes instead of wire at wherever the road salt and moisture likes to sit.