p0440 code coming up

My 02 tacoma 2.7 keeps coming up with this code. I reset it and two days later it pops again. my reader says it's - powertrain evaporative emission control system. Everyone i have questioned about it says it could be a simple gas cap leak to a major emission issue. Nothing is wrong with my truck. It runs exactly like it did before this code came up. The only thing i think is odd is that i can smell fuel when i get out of my truck. i'm not leaking any i can just smell it. any help would be great. I did the simple thing and tightened my gas cap but the code still comes up after i clear them.

 

"Everyone" is correct.

Most common cause of a CEL is the gas cap is not tightened until it clicks.
2nd most common cause is aftermarket gas caps that don't properly seal.
3rd most common cause of that code is the owner is in the habit of topping off the tank. This causes liquid fuel to get into the evap canister, saturates the activated charcoal, and it can no longer do it's job... system fails the test and throws the code.

 

Best simplified explanation ever.

 

50% of the time its a gas cap, but since you are smelling fumes I bet it is your charcoal canister. It could be a solenoid valve that's attached to the canister or a bad relay/fuse that's not allowing the valves to open/shut properly... but I'd bet a dollar it's the canister itself. When you buy the canister, it'll come with a new CCV solenoid.

 

Where's the canister on the 1st Gen?
2nd Gen it's above the tank in the rear.

 

It's above the front driver wheel well.

 

I got this code too, two days after driving mine home from the dealership
Turns out that my Purge Valve was completely disconnected
I plugged it back in, and after I took a 30 mile trip, the light went off and has never came back on
...Doubtful yours is unplugged; but, it might be going bad

Here's some other things to try:

With a P0440 OBD-II trouble code, diagnosis can be tricky at times. Here are some things to try:

• Remove and reinstall the gas cap, clear the code, and drive for a day and see if the codes come back.
• Inspect the EVAP system for cuts/holes in tubes/hoses
• Inspect for damaged or disconnected hoses around the Evap purge solenoid
• Check and/or replace the sensor
• Check and/or replace the purge valve
• Have a professional use a smoke machine to detect leaks

 

Thank you all for the replies. I only fill my tank till the nozzle clicks. i hate people that fill the neck of the tank. Doubt it's the cap. I always tighten it till it clicks three or four times. Might be a bad seal on the cap but i'll check the connections and lines of the system and check the canister. My local dealer is going to smoke the system when i bring it in for my recall on my spare tire carrier.

 

Good info-never thought of the overfill going into the canister-Nice.

 

Alright, cleared the codes and filled up this afternoon. Cleaned the cap o-ring and cleaned the filler neck spout. when i pulled into the driveway i smelled fuel again but it'll take a day or two for the code to pop if it does. Hopefully it is just the cap because i really don't want to spend 260.00 on a new canister.

 

Probably the canister... I know sucks, but at least it comes with the two New valves

 

If you're still smelling fuel, the code will come back.

 

I wonder if he found the issue?

 

I haven't brought the truck to the dealer. When i first bought the truck six months ago it idled odd. Some times it idled at 700 rpms but most of the time the idle was fast like 1650-2000. Now that this fuel smell and check engine light came on, my truck idles smooth as 650 and i am getting better fuel mileage. Mileage might be coming from the warmer weather we are getting in wisconsin but i really don't want to spend the 260 dollars on the canister just to get rid of the light right now. everyone tells me it's the canister.

 

I had the same issue on my 02 taco. It's a 2.4 liter 4 banger. I was smelling fuel and checked the canister. It was saturated and a valve on the canister wasn't working. I bought a new canister and replaced it myself. I also still have a 440 code active. A mech hooked it up to his laptop and showed me the live diagnostic for the entire evap system. The fuel vapor pressure sensor (which sits in the top of the tank) is flatlined at a reading of .02 psi. It won't "read" any other pressure in the system.
So now I'm replacing the sensor.

 

I've also had this code come up on several occasions after switching brands of gas

I've got the code on 93 Conoco Non-Ethanol and 92 (or 93, can't remember) Mobil
I've NEVER got it on Chevron 92

 

any updates on this? replaced my charcoal canister and gas cap (all OEM) and still getting this p0440 and now i cant get my truck registered!!

 

Did the canister come with new solenoid valves? If it did the only thing I can think of is a fuse/relay isn't activating a valve or the canister isn't hooked up right. I know a dude that forgot to hook up the tiny hose.

 

yeah the canister came with all new stuff... same light is on so im guessing i now have 2 working canisters haha lucky me. and im pretty sure i got it all hooked up right, there were no hoses left over!

 

wanted to find out if the above guy got it fixed because im having almost the exact same issue and would love to narrow it down to not the charcoal filter. Gas cap on mine is good. Hoses do not seem bad either.