CHARCOAL CANNISTER and OXYGEN SENSOR REPLACED & did a SMOKE TEST too.............

I have a 2002 Tacoma 3.4 (4x4) and my truck failed our STATE EMISSIONS......The check engine light has been on for a while and I had it SCANNED and P0440 code came up.....

• The repair shop did a "smoke test" and it was determined that I needed to replace my Charcoal Cannister, in which I did.... I also replaced the oxygen sensor (the one near the catalytic converter) (I also replaced the GAS CAP too....with a FACTORY toyota gas cap from the dealer) In fact all of my parts I purchased from my local TOYOTA dealership.

3 days later, my check engine light came back on and had it scanned again and the same code re-appeared (P0440) and it also said: EVAP CONTROLLER.



My question is: I am not familiar with an EVAP controller, (do I have 1 or 2 EVAP controllers) and where are they located (Its not part of the Charcoal Cannister that I just bought is it?

How expensive are they? How much would the labor costs be?





Thank you!!!

 

Hi Frank, I am sorry to read about your problem. You did a smart thing letting them smoke check your system and this may not be a hard problem to fix. Here is a link to a picture that shows your VSV for Evap . The VSV valve is usually mounted on the fenderwell area, at least by the picture. There should be two VSV valves close together, both go to the canister. One easy way to trace them is to look for a medium size vacuum hose near the EGR valve on the rear of the engine, that runs over to the fender area and connects to one of the VSV valves.
You can remove them one at a time, and if you have a multimeter, set it to measure Ohms and see if it has a open or closed circuit. Unplug the wires that go to the VSV valve and check the wires of the VSV and if the Ohm meter reads an Open circuit the numbers will more than zero. If the valve is bad, it will trigger your light again. I do not know how much those valves are, but there should be almost no labor to replace them. I don't know how soon you need to retest to get your Emissions sticker. If you have the time and find out which of the two are bad, you can order it on line and save some money. I hope this helps, Good luck.

 

Thank-you for the helpful information!!!I really appreciate it!

 

I also had a similar issue and read plenty about having the charcoal canister replaced and the light coming back on a few days later... So after testing all of the VSV's and trying to do some vacuum tests on certain portions of the Emissions system and not being able to determine anything concrete I decided to find a good independent mechanic to tackle the job. They were able to pressurize the system and spray soapy water onto some of the hoses and components to see if anything bubbled - pointing to an air leak. Turns out it was the rollover valve on my gas tank that was giving me a leak in the system. Now he did say that it was an odd part to fail but it seems he was able to pinpoint. So maybe have someone look at the vehicle and test portions of the tank to see if the leak is there.

BTW I had a P0440 and a P0446 so i'm not saying you have the same problem but just trying to help provide any input that my solve the issue....

Like Ga Tacoguy said, check the VSV's first and see if that is the issue... then maybe start checking the tank.

 

UPDATE:

Well, after I replaced the Charcoal Canister and the Check light came on 3 days later!!!!!!!!

I took it back to the shop and they still couldn't figure it out.

So, I decided to take it to another shop, my local toyota dealership. They worked on it for 4 hours, testing a bunch of things and they couldnt find the problem. They want me to bring it back and leave it so they have more time to work on it.

The next thing that the Dealership wants to do is to DROP the GAS TANK and PRESSURE TEST it and also check all of the lines and hoses that connect to it. They will also check the seal around the sending unit etc.

If anyone else experienced this or has any suggestions, please feel free and let me know.........

THANK YOU

 

I forgot to mention that the VSV valve was tested and was fine. Also numerous things were tested as well as a SMOKE TEST was done to detect any possible leaks.....

As mentioned above, I will tell the Toyota Dealership technician to check the rollover valve on my gas tank so see if that was giving me a leak in the system.