Check engine light!

When you have the time, please post or PM your vehicle information. I need year, make, model, body style, 2wd/4wd, transmission (auto or manual) and if you have ABS. Yeah, it's a lot of what seems irrelevant info, but to "build" your truck in the diagnostic charts, it asks for all of this.

 

It's a 2004 Toyota tacoma 2wd double cab automatic transmission. And yes I have ABS. Thanks for all you're doing to help!

 

ABS?

2004 probably does

 

So this is going to take some time for self diagnostic. A P0456 is for a very small evap leak. I know you have started off with some things already, but I am going to list the general checks to run:

1. fuel cap (is cap OEM? Seal condition good?)
2. filler neck (Is the sealing surface on the filler neck dirty?)
3. vacuum hoses (inspect ALL hoses for leaks, damage, pinched hose)
4. test purge valve at engine

• disconnect electrical connector of purge valve.
• disconnect vacuum hose that does NOT lead to engine
• start engine
• is there vacuum present at the purge valve that you disconnected the hose from?
• if ANY vacuum is present, the purge valve is bad.

Let's start with that and go from there.


The purge valve is also called the VSV for EVAP. The vent solenoid is commonly called the VSV for CCV.

 

Antilock braking system! And yes it does, thanks!

 

Well, there's no vacuum present at the purge valve at all!

 

I wrote that literally a second or two after you edited your description to include whether it had ABS or not

Hope you get it worked out!
And welcome to TW!!

 

I edited my description to add a thank you to bamatoy1997 for all he's doing to try to help me. I've known my truck has had ABS since I bought it years ago. Just because I'm a girl, doesn't mean I don't know anything about my truck. Anyways, have a nice day!

 

...I think there's some miscommunication here



Your (unedited) post didn't specify whether or not you had ABS, which is one of the things Bama had asked you
So, my message "ABS? 2004 probably does" was to remind you to include that info; so you'd get as quick of a response as possible
But, you apparently realized that and beat me to the draw with the edit, which added "and yes, I have ABS. Thanks for all you're doing to help!", before my post hit the thread: AKA: "I wrote that literally a second or two after you edited your description to include whether it had ABS or not "


Has nothing to do with being a girl or thinking you didn't know
Just cause I'm a guy doesn't mean I think girls don't know anything about their trucks

Still hope you get it worked out soon!
Take care

 

ok, need a bit more detail please. When you say there is no vacuum at all, at what point did you test it? There will be no vacuum of course if the engine is not running. Did you do exactly the same test as described? No, not calling you out as a girl, I promise. It is just when doing a long distance diagnostic like this I like details so that I can be 100% sure before I recommend replacing anything.

 

Yes, the exact test was done step by step and the engine was running.

 

OK, then we should be able to pretty much eliminate the Purge solenoid as the fault. Did you inspect all of the vacuum hoses, even down to the Charcoal canister? Next would be to find the vent solenoid and inspect it for dirt, or mechanical problems. Those are harder to test because they are a normally OPEN solenoid, instead of normally closed. You would need to find a way to energize the solenoid while blowing into one end of it and see if any air passes.

Sorry for the delays. I have been busy at the shop, and trying to help several members on here as well.

 

Tested both valves by the fuse box and they both opened and closed tightly. I assume that the valve with the long hose going to the air filter is the vent valve?

 

OK. Now the bad part, the pressure switching valve is located on top of the fuel tank, next to the large charcoal canister. That would be the next solenoid to test for operation. If you can't find any problem there, then that is the best I can offer for online diagnostics. A smoke test would need to be performed at this point to check all seals.

 

Do you have a diagram or know where I can find one of an evap system for an 04 Tacoma?

 

I know this thread is a few months old, but did you find the solution?

In the assumption that you did, what was the final test/outcome?

 

Sorry for missing that you replied so long ago Julie. I am guessing you found the problem. If not, let me know and I can get back on helping you.