SC 430 Code P0440 and P0446
 

Check engine light came on and Codes P0440 and P0446 are indicated. Has anyone had experience with these? I had just made a 1350mi trip and everything was fine. When I started back home the check engine light came on - the out-of-town dealership told me they thought it was the gas cap. They reset the indicator and all was well until I got home and the check engine light came on again, this time the local dealership told me it was the charcoal cannister and charged me $1,100. to replace it. The next day the check engine light came on and now they are going to replace the gas cap (at no-charge)!! They had to order the gas cap and said it would be OK to drive - this time when I left I had the VSC and VSC-off lights come on in addition to the check engine light. I am thinking that the dealership should have started with replacing the gas cap which is maybe $50. and if that didn't work, then look for other solutions.

open the hood, on the driver side valve cover, there is an evap line with a green cap, inspect the hose for disconnect or cracked. It leads to the purge solenoid of the EVAP.

Your Vent valve is on the passenger side of the valve cover, it's a solenoid that hooks up to the intake. The VSV itself could be defective or you got some broken hoses.

The search function is my savior. I just got this same code today:p0440, I came across this thread and low and behold, I checked the first thing mentioned regarding the EVAP line with the green cap and the line was disconnected.my check engine light is gone for the time being because I already erased the codes so hopefully it doesn't come back. Thank you GS4_FIEND!!!!

Me too
 

@sLOWaristo Did your fix attempt resolve your issue?

@SC43062 My scenario is similar just different solutions were tried. Ahhh these evap issues are so frustrating. I went to my car guy 4x over this! Started with generic P0440 error.

1st time, he replaced the fuel cap, code returned. Cleared the code but P0440 returned.
2nd time, he replaced one of the evap hoses. Cleared the code and same code returned.
3rd time, he dropped the fuel tank, did smoke test which turned out ok no leaks and replaced the overfill valve because it looked worn out. Cleared code. Two days later, I got these codes below!

P0440 (current)
P0446 (current)

P0440 (pending)
P0441 (pending)
P0446 (pending)

Car guy introduced new codes! I am really annoyed. Not just the original code but 2 new ones, P0441and P0446. So 4th time, he checked all the hoses and replaced the ones he didn't replace the 2nd visit. I don't remember him doing the one with green cap on the passenger side like another member mentioned here. He cleared the codes and I drove over 100 miles but now the P0440 and P0446 returned both showing as current codes and also pending codes. What is going on!

I don't want to bring my car back again yet so I will attempt to check the green cap. Ugh. It's been 10 years since this thread was opened so I hope I can get some helpful advice and tips from whoever sees my post.

EVAP Codes 440, 441 & 446
 

Aloha,
having same issues with my 2002 SC430, with
approximately 86k miles. Been having issues for
past couple of years & Low gas mileage aswell.
When I drive for longer distance than normal check engine light doesn't come on until the next time I use the vehicle. My normal commute to work is only about a mile to work in each direction & no CEL comes on at all. Again only after longer distances. I'm researching now to narrow down the possibilities & am hoping I can fix it with just changing the Vapor canister purge valve Doorman part # 911-488 or I believe the Vacuum Switching valve/ vent valve. Charcoal canister price new over $700. Used anywhere from 100 to 300 buy you never know how much mileage donor vehicle had;
probably more then mine. I suggest to keep researching on line & look at different videos before bringing to shop; who will probably do the same thing. Good luck, Happy Blessed Holidays & God Bless You & Yours.

Thanks @Lexsalot that's so early for your car to be having issues at 86k miles! Too late, I dropped my car off on Tuesday and have not heard from my car guy yet. Maybe he is still figuring out what the issue is since he tried all the other fixes. Who knows but he better resolve it bc I do not want to bring it back again. The remaining possibilities from my research is the vapor pressure sensor or the solenoid from the charcoal cannister or the entire thing. What a headache. Good luck to us!

Replacing charcoal cannister
 

After having my SC430 in the shop for 2 weeks now, my car guy is replacing the charcoal cannister and he just called saying it is all done today. He tested everything possible but only the likely thing is the charcoal cannister. What an expensive repair! This better be the thing that makes these codes go away!!! I will report back after driving for a bit after the repair and clearing the codes.

Both error codes came back!!
 

Oh my goodness this is madness!! These codes are stubborn. What in the world! I have been researching and asking around. My car guy is stumped. Other people say this is very unusual to still be an issue since there is no leak and all the big stuff has been replaced. Ugh!!