Code P0456 - When its not the gas cap

[McGyver9]

So I guess I can't post pictures either yet?

 

[McGyver9]

Uggghhhh

 

[McGyver9]

4Runner - Google Photos

 

[McGyver9]

What did you find out?

I’m going to my mechanic on Thursday. I need to try saving a few bucks by giving him ideas to check out. I’m on my 3rd gas cap to resolve lights being on. This time, it’s not the gas cap. I have no pressure release when taking cap off. Help, please.. thank you in advance.

 

[fatherdoug]

well its been weeks and no more light!

Anyone who has evap issues, this is a MUST READ:

Be a Toyota leak detective - Automotive Service Professional

The system is more complex that I had thought. It does tests after the car has been off for 5 hours, thats why the light comes on in the morning.

Excellent information! Would it be possible to make this a sticky at the top of the forum?

 

[RML17]

What did you find out?

Brake light switch.

 

[Ron_Mexico]

So on Saturday night when I went to fill the gas tank I dropped the gas cap on the concrete ground. I checked for any signs of damage on the cap but didn’t see anything noticeable. Today when I’m leaving work check the engine light is on and did a scan. I get a code P0456, I’m not sure if it’s coincidence or I damaged the gas cap by dropping it the other day. There was no check engine light this morning. What do you guys think? I cleared the code and put the old gas cap back on. I’m currently awaiting to see if code comes back on.

 

[AuSeeker]

So on Saturday night when I went to fill the gas tank I dropped the gas cap on the concrete ground. I checked for any signs of damage on the cap but didn’t see anything noticeable. Today when I’m leaving work check the engine light is on and did a scan. I get a code P0456, I’m not sure if it’s coincidence or I damaged the gas cap by dropping it the other day. There was no check engine light this morning. What do you guys think? I cleared the code and put the old gas cap back on. I’m currently awaiting to see if code comes back on.

The gas cap should have tether that's attached to the vehicle so you can't drop or loose it, I would get a OEM replacement if only just for the tether.

 

[Ron_Mexico]

The gas cap should have tether that's attached to the vehicle so you can't drop or loose it, I would get a OEM replacement if only just for the tether.

The tether is still on gas cap, the other end attached to the fuel door popped off, allowing the cap to fall to the ground.

 

[TTucker]

Thank you for this post.

 

[Smitty4thGen]

Hello all. I dont mean to hijack but the op is kinda old. My 04 has the evap codes and i have replaced gas cap, the valve by the intake manifold (sorry the name escapes me) and all the hoses under the hood but the codes keep returning.

I bought a smoke machine and tested it today. The smoke was venting from the fuel fill area but NOT the cap. It seems to be coming from around the base of the fuel fill neck.

I cant find any other instances of people experiencing this and i dont know if i need to replace the whole filler neck or if there are smaller parts i can replace to maybe fix the leak???

Thanks in advance!!

 

[AuSeeker]

Hello all. I dont mean to hijack but the op is kinda old. My 04 has the evap codes and i have replaced gas cap, the valve by the intake manifold (sorry the name escapes me) and all the hoses under the hood but the codes keep returning.

I bought a smoke machine and tested it today. The smoke was venting from the fuel fill area but NOT the cap. It seems to be coming from around the base of the fuel fill neck.

I cant find any other instances of people experiencing this and i dont know if i need to replace the whole filler neck or if there are smaller parts i can replace to maybe fix the leak???

Thanks in advance!!

The only way to know where the leak is, is too locate the exact point of the leak..."seems to be coming from around the base of the fuel fill neck" is not exact enough for anyone to help you, something is either cracked, loose, has a hole in it, etc., you have the smoke machine so it should be rather easy to find the exact point of the leak, no one can find it for you on the forum, we can't see where the smoke is coming out.

 

[Jakeepoo3]

Nice trouble shooting original guy. I'm sure this thread has helped many folks out there that know their gas cap is good. Now on to the even more fun part. EVAP system delete For all you guys out there focused on performance and not having filthy fumes entering your a/f. F_cking up your engine with deposits and causing cats to go bad no matter how well you maintain everything. Well, it's easy on a truck like my 94 Cherokee XJ which does not monitor the EVAP system. Just tear it out, cap the vacuum inlet on intake manifold, and seal tank with a vented gas cap. Now how to do it on the 5th gen?? Getting rid of it is easy but how will we convince the computer everything is normal.. I haven't gotten into the electrical/computer part of this yet. Once I do figure this out I will delete the trashcan system. No, I don't care about the law. Please don't mention that as these laws are for sheep who neglect and can't understand maintaining pcm inputs and Stoichiometric ratio. Thinking on how to trick the computer.. simulator, diy tuner?? I want this crap out of my truck.

 

[Smitty4thGen]

The only way to know where the leak is, is too locate the exact point of the leak..."seems to be coming from around the base of the fuel fill neck" is not exact enough for anyone to help you, something is either cracked, loose, has a hole in it, etc., you have the smoke machine so it should be rather easy to find the exact point of the leak, no one can find it for you on the forum, we can't see where the smoke is coming out.

i had trouble uploading here so i put the video on youtube. here is the link:

IMG 3714 - YouTube

 

[Smitty4thGen]

The only way to know where the leak is, is too locate the exact point of the leak..."seems to be coming from around the base of the fuel fill neck" is not exact enough for anyone to help you, something is either cracked, loose, has a hole in it, etc., you have the smoke machine so it should be rather easy to find the exact point of the leak, no one can find it for you on the forum, we can't see where the smoke is coming out.

i had trouble uploading here so i put the video on youtube. here is the link:

IMG 3714 - YouTube

 

[AuSeeker]

i had trouble uploading here so i put the video on youtube. here is the link:

IMG 3714 - YouTube

That video still doesn't help anyone here to help you find the source of your leak, here's a photo of what you can't see looks like, take your pick as to where the leak is because that's all we can do from your video.

 

[Jakeepoo3]

That video still doesn't help anyone here to help you find the source of your leak, here's a photo of what you can't see looks like, take your pick as to where the leak is because that's all we can do from your video.

Right I can't tell if it's coming from underneath with that video. Can you look under that spot to see if it's rising from another area? Bust out some tape or something if you can't see. Tape or whatever works to check all the seems joints and what not. You might have to get under the truck..