p0440 code coming up

well went to change my spark plugs ended up not getting any spark with old or new spark plugs. Finding out I may have some serious electrical issues. The EFI relay is now buzzing and cant get a spark. May have a short tearing the truck apart now. Weird thing is the EFI relay is starting up the fuel pump still. Relay is good but clearly buzzing. Tried other relays same thing cant figure this one out and nobody seems to know. Its definitely an electrical problem at this point. Now its winter and my truck is out of commission time to buy a second car to get around.

 

Well I had the same problem and went trough hell and changed a lot of stuff, the cap, injectors O rings, PVC valve, the tank filler neck, the canister (but that was bad, broke) and at last was something that nobody has mention. The gas pump gasket was bad, was cracked and like rusty from the tank. If anyone look at this please check the gas pump gasket.

 

Good tip!

 

So as far as the clicking noise in the fuse box. A ground wire was destroyed and not fully connected. So if you are having an issue with starting sometimes but not others and all fuses good it could be a ground wire. Check your ground wires. The hard to find ones.

 

When you say gas pump gasket are you referring to the gasket for your fuel pump or something else. Did you have to drop the tank to access this?

 

Yes, the gasket from the fuel pump. And yes, you have to drop the fuel tank. This thing was driving me crazy. After I changedon't this gasket the code went away. And the gasket was all cracked and broken around where the screws goes. Good luck, hope this helps.

 

Got my 2002 with 214K miles, filled up, and almost exactly 100 miles later got a P0440 - gas cap. Replaced the cap and cleared the code by disconnecting the battery. CEL stayed off.
100 miles after next fill-up, got P0440 - gas cap and cleared it with my code reader. CEL stayed off.
100 miles after next fill-up, got P0440 - gas cap and cleared it with my code reader. CEL stayed off.

So, 3 times in a row got CEL 100 miles after fill-up, cleared the code and it stayed off until 100 miles after the next fill-up.

Any thoughts or recommendations?

 

Pretty sure I'm also having the fuel pump gasket issue. 2001 4x4 Xtra cab. Last fall I slapped a bunch of gasket maker around it (so I didn't have to drop the tank) just to see if that would do anything. Cleared the code and it didn't come back for the whole winter, until today. I had always still smelled gas, so it makes sense that it wasn't solved.

I'm pretty convinced it's the fuel pump gasket. When dropping the tank, how do you unhook those fuel line connectors? The in-line ones. They look like little plastic things that are doomed to break. Thanks for any info

 

It takes several cycles for EVAP codes to cause CEL on. 100-150 mi and 1/2 tank gas or less.There is also a temperature differential required as well as engine on off cold and hot required.
Also quit disconnecting the battery to turn off CEL. When the problem is fixed the CEL will go off automatically.

 

The clicking is the purge selnoid next to fuse box

 

On the 6cyl 3.4L yes

 

I took my '02 PreRunner to a shop that smoke tested it and found 'something' leaking on top of the tank. The shop AND dealer both suspected the rollover valve (vent valve) on top of the tank. So, I bought a vent valve (~$105 OEM), the grommet for the vent valve, and the gasket for the sender/pump. I dropped the tank and found the entire top of the rollover valve cracked off except for one small bit of plastic still holding where the small tube comes out. I'm sure the rollover valve was the source of gas fume smell near the filler when I would park the truck. Also, the rollover valve grommet had radial cracks all the way around but not yet bad enough to cause a leak.
Entire job took 7 hours. Hardest part is unlocking the fuel line (special tool at AutoZone), and figuring out how to unlock the two electrical connectors. The last thing was unlocking the large hose that connects the rollover valve to the charcoal canister. By that point I was tired and frustrated and ended up breaking the lock on the hose. Fortunately, my Toyota dealer 3 miles away had a new hose in stock for $30.
I've got 62 miles on it and no P0440 code (previously I would have gotten the code within 40 miles of resetting it).

 

I think this is whats happened to mine I took it to a mechanic and they changed the canister but its still shaky on startup and has the po440 code

 

Were you getting a check engine light

 

I threw this code a few months ago. I tried the gas cap and I eventually solved it with a new vapor canister purge solenoid in the engine bay like others have mentioned. Took a few miles before the check engine light went away.

 

This is a 10 year old thread

 

Good catch. You were 40 min late from saving me from wasting my time