2003 Avalon P0441 P0442 P0446

[wleeb]

My wife's '03 Avalon cannot pass state inspection because it keeps throwing DTCs P0441, P0442 and P0446. I purchased a new OEM gas cap from Toyota and reset the MIL but it came back on a couple of days later.

I then took it to a mechanic and he performed a smoke test and didn't find any leaks but said there was a TSB out on the VSV for CCV valve so he replaced it and the MIL came back on about a week later.

I gave up on the mechanic and started systematically replacing the remaining parts in the vacuum loop one at a time but the DTCs came back every time.

To date I have replaced the following parts:

• VSV for CCV
• VSV for EVAP
• VSV for Pressure Switching
• Charcoal Canister
• Gas Cap

The only other parts that have not been replaced are the Vacuum Surge Tank and Vapor Pressure Sensor on the fuel tank.

I'm not sure what is going on? Any help would be greatly appreciated.

Thanks,

[TrailDust]

Just throwing this past thread out to you, which has a couple of worthwhile links in it.

[wleeb]

My wife got home this afternoon and I crawled under the vehicle and examined the vacuum hoses at the gas tank and noticed that the hose to the tank overfill check valve was completely off. This hose has a compression clamp, so I do not see how it could have worked its way off, maybe sabotage from one of the shops the car has been too? The codes had to have been coming from the loose hose since it would create a gross loss of vacuum.

Anyways, the vehicle is back up and hopefully no more DTCs.

[TrailDust]

Glad to hear you found that. Hopefully that will take care of the issue!