I have a 2007 F-150 STX 4x4 4.6L V8

The CEL code P0446 just will not go off. I took it into AutoZone and they gave me this description:

Definition:
EVAP(evaporative emission system) purge/vent solenoid circuit condition
Explanation:
The solenoids and system wiring are monitored for opens or shorts
Probable cause:
1. Purge or vent solenoids defective
2. Check connector and wiring
3. Fuel saturated vapor canister
4. Failed EVAP vent solenoid

I've taken it in to the dealer, and they determined it was a wiring problem. So they replaced the entire wiring harness(under warranty), the light DID turn off for a while, but it came back within a week. This was a few months ago, I just haven't taken it back in.

I've noticed that when I'm parked on somewhat of a steep slope the light will turn off. But as soon as I get back on the road and turn it off, the light turns back on. I'm wondering if it's just not mounted on right? I don't think it can still be a wiring problem considering they replaced the wiring harness.

I'd just like some leads so I know where to start. I've tried searching for some sort of diagram to show me where the purge/vent solenoid is at, but I haven't been able to find it. So if someone can at least guide me around the engine or something like that.

If you have any further questions that might help me out just ask. Thanks.

 

try installing a new gas cap

p0446indicates that self test has detected the evap systemhas excesive vacuum or vent control malfunction

possible causes are blocked or kinked hoses

contaminated canister

restricted canister

purge valve stuck

vref open to ftp sensor

damaged ftp sensor

 

Still on warranty? Take it back in.

 

Sorry I forgot to mention that I've already replaced the gas cap. I picked one up at AutoZone.

Is there any sort of diagram out there that I can use to go around and look?



The time I took it in they said that if it was the purge/vent solenoid it wouldn't be covered under warranty. But I've recently learned about the Emissions Warranty but I couldn't get a good answer on if that would be covered.

 

Take it to another dealer.

 

auto zone gas caps are no good. i bought one for my truck and had to get it smogged, the autozone gas cap did not pass smog. maybe try buying one from ford? just a thought