not ANOTHER p0446 code!

Yep, It is ANOTHER thread about some EVAP system codes lol. I need to know a few specifics things. Can't seem to find them anywhere else.

Anyways my truck keeps throwing P0441, P0442 and P0446 codes. I erased them, and they come back after about 15 miles of driving. Latest time only P0442 and P0446 came on.

Gas cap is in great shape and an OEM Toyota one. All the vacuum lines looked great. Pulled all 3 of the VSV and bench tested them (hooked them up to power and confirmed that they allow/cut off air when correct voltage is applied)

Next step according to fsm is the canister. This is a very expensive guess, but seems likely after everything else I have looked at checks out. Anyone know of a way to bench test the canister on my truck? (04 3.4L Manual)

Any other advice would be great! feel free to ask me any questions I have not been in for an official smoke test. I know I should go do that in case of a leak, but everything looks great!

 

Take it to a mech shop and get them to smoke ur evap system. It will show any signs of leaks from it

 

does a bad O2 sensor throw that code?

 

Not for evap no two completely different systems

 

I was going to go get a smoke test as a next step, assuming there is no bench test for the late style canister that is on these trucks. I have yet to do it, Let you guys know if I figure it it out and the results!

 

When you can't find an obvious problem, then a smoke test is always the best answer. Better y to pay a few bucks to get it tested and KNOW what to replace, than to guess at it and be wrong in an expensive way. Canisters are not cheap, and while not impossible, rarely fail a leak test.

 

Bill has arrived, any questions ask this gentleman he knows his stuff

 

Okay small update folks,

I have driven my truck about 60 miles since the 3 VSV bench tests. No light yet! Before it had been coming on every 15-20 miles consistently. I know it can take a couple hundred miles for an EVAP code to come back on, but fingers crossed I don't see it again.

I wonder if one of the VSV's maybe was semi frozen and jolting it a few times loosened it up? Also, could have been one of the hoses on one of them that was starting to come loose and when I put it back on it made it air tight again.

OR another thought. This time around, I used the OBD2 scanner to clear my CEL codes. Whereas before I only unhooked the battery for a few hours. The OBD2 scanner was showing the P0442, P0446 and was showing 3 "banked" codes as well (P0441, P0442 and P0446) I assume "Banked" means it was from last time? I am not sure though. Can anyone elaborate? For now, I will drive on and report back when/if it comes back on (course now that I post this, it is sure to)

 

Typically disconnecting the battery will clear the codes. P0441, 0442, and 0446 all are called "B" codes, which means that they have to fail twice in consecutive tests before setting a light. It may be possible that your testing and disconnecting things may have fixed the problem. It could have been a simple bad connection. Hard to tell until you get enough drive cycles. If you want to try forcing it into a test here is what you can do: Make sure your fuel level is above 1/4 tank, but less than full. Allow engine to sit overnight and cool down completely. Start the truck, let it idle for a minute then go drive the vehicle on the highway for a good steady 10 minutes, around 45MPH or more. Don't gun it, or decelerate a lot. Try to keep a steady speed. Finish the day and return home, let it sit overnight again and perform the same test again. All you have to do to force the test is start in the morning with a cold engine, and on the FIRST drive of the day, have a steady acceleration and drive time. Driving to the gas station at the corner and turning off the engine to go grab a soda will cause the system to reset the basic test until the next "cold" engine restart. The rest of the day you can drive however you want.

 

It's a shame I live 3 miles away from work or could do this in the morning lol. I will definitely try it asap! Thanks for the info man. I'll let you know shortly!

 

Here we are a good 3 days later. Had the chance to run it first think in the morning steadily on the highway and nothing has come back yet. Looks like I got lucky messing with some of the connections or something Let you all know as soon as it comes back from me jinxing it just now