This P0440 is driving me nuts! Sanity check?

[4flyer]

So, I have been troubleshooting a P0440 code for a while now in my 2001. Once and a blue moon, a P0446 would also come up. My annual inspection is now overdue because of this.

Smoking gun? For two or so years now, the gas pump will turn off prematurely at some gas stations. I also had a bad habit of topping off the gas tank. I do NOT have a gas smell that many report.

I assume that it is the evap system so I have been going down the list.

I inspected all the hoses. They look alright. Not amazing though. There was a split on the end of a hose going into the engine bay from the charcoal canister. Looks to be still sealing but I put some silicone on the fitting to further seal for now.

I removed and inspected the charcoal canister. It looked fine and I could not find any cracks. While I do not have a vacuum gauge or pump, I did my best to go through the inspection routine in the FSM. No clear issues there. No fuel came out of the canister but it did have a slight fuel smell as I would expect. I tested the VSV valve that was with the canister assembly and was fine. I reinstalled the charcoal canister. Lo and behold, the code came back.

I now ordered a overfill check valve. I really don't want to drop the tank but I will if I have to.

Anybody suggest where to look next? Think it is the canister? Think it is the overfill check valve?

Thanks!

 

[2001 Limited 285K]

To get my '01 through inspection, I just bought an Actron and cleared the 440, 441, 446 codes. $50 and problem solved for a year. Mine are so sporadic that I haven't bothered to fix them because it seems like more trouble than it's worth. Especially dropping the tank and doing all this: GAS FUMES P0440 P0446 Fuel Check Valve Replacement Toyota 4Runner √ Fix it Angel - YouTube which I don't have the room or really the time to do. Although I do have a charcoal canister inspection on my list of things to do since it seems pretty easy to remove and inspect and fix if needed.

 

[jgue467]

So, I have been troubleshooting a P0440 code for a while now in my 2001......
Anybody suggest where to look next? ...

Have you replaced the gas cap?

 

[19963.4lsr5]

So, I have been troubleshooting a P0440 code for a while now in my 2001. Once and a blue moon, a P0446 would also come up. My annual inspection is now overdue because of this.

Smoking gun? For two or so years now, the gas pump will turn off prematurely at some gas stations. I also had a bad habit of topping off the gas tank. I do NOT have a gas smell that many report.

I assume that it is the evap system so I have been going down the list.

I inspected all the hoses. They look alright. Not amazing though. There was a split on the end of a hose going into the engine bay from the charcoal canister. Looks to be still sealing but I put some silicone on the fitting to further seal for now.

I removed and inspected the charcoal canister. It looked fine and I could not find any cracks. While I do not have a vacuum gauge or pump, I did my best to go through the inspection routine in the FSM. No clear issues there. No fuel came out of the canister but it did have a slight fuel smell as I would expect. I tested the VSV valve that was with the canister assembly and was fine. I reinstalled the charcoal canister. Lo and behold, the code came back.

I now ordered a overfill check valve. I really don't want to drop the tank but I will if I have to.

Anybody suggest where to look next? Think it is the canister? Think it is the overfill check valve?

Thanks!

The gasket surfaces on top of the tank can rust and cause a vacuum leak. There are two rubber gaskets.


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[19963.4lsr5]

Here is an example


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[4flyer]

Thanks for the info! For me, it was the charcoal canister!