Hello people... new to this thread.
I have a 2006 GMC Sierra crew cab; 5.3L, Z71. About a year ago, it threw the P0446 code. I replaced the canister at that time. Since then, the CEL comes on about every 3 months with the same code. I would just clear the code and not worry about it. Now, it is time to get the bi-annual emissions test. I stopped by the GMC dealership and picked up another solenoid kit ($180 - ouch) and plan to put it on in the next few days. I assume the replacement solenoid I installed is bad but (being an electrical component) they won't take it back. I plan to blow out the line and replace the unit and canister. Is there anything else that I should do while under there?
Question: What does this silly solenoid do? Does it serve any useful purpose or is it just un-necessary complication? Seems to me that a simple check-valve to allow a little air in when needed as fuel is being drawn out would suffice. <Gripe off>
I have been a member of several other forums and appreciate the opportunity to learn from you guys. This thread has been particularly helpful :great:
The first thing that needs to be checked with P0446 is if the fuel tank pressure sensor is reading correctly, with the fuel cap off it should read atmospheric pressure. If it reads correctly the vent solenoid is the likely culprit.
this code can be from operating in dusty off road conditions or overfilling the fuel tank then parking after a short ride in a hot/warm area. avoid parking with the front end down when full..
the vent lines get fouled with charcoal from the canister , when the overfill cause is responsible.
Thanks for the replies. Here is an update to my original post. I got under the truck to replace the unit and realized that the hose had a crimp in it. I cut a longer piece and used a wire tie to hold the longer hose away from the driveshaft. I reset the code and have driven it for the last week. I put the code reader on it and there are no pending codes. The problem is fixed. :great:
Hello, new to the site. I have the PO446 code on my 2000 Silverado 4x4 extended cab long bed. Tried to locate the canister but not sure I found the correct part. It was in between the cab and bed on top of the gas tank. Really hard to get to and wasn't able to disconnect it to try and blow it out. Can anyone post pictures of location and how to get it loose and disconnect the hoses for this year of truck? Thanks
I'm working on this issue in my 04 3500 6.0L. I have a P0446 & P0452 codes. Both the vent solenoid and fuel tank pressure sensor are new. The vent solenoid is the updated style with filter and the pressure sensor came with the new sending unit that I installed. The old unit was rusted out and leaking fuel everywhere. Thanks!
If one of the plastic lines were pinched, can you engineer a patch with regular vacuum line? I'm not sure if this is the reason for the p0446 code coming up once in a while, but I've checked everything and clean out as much as I can. The code started popping up when I replaced the fuel pump a few weeks ago. All the connections are solid. Also... everyone has pics of round canisters. The one on my Denali is like a rectangle-box. It's mounted forward on the side of the fuel tank. Attachment 56323Attachment 56324Attachment 56325
go to the dealership and get a new line. this is not that expensive. 30 uSD..
easy on these lines with these SUV types the lines must be carefully positioned on a tank drop/install..
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with the pickup the canister is not on top of the fuel tank. the canister is between the fuel tank and frame rail. you will see hoses of 3 different sizes going to it . using tools to release the lock ring these slide off. if the hoses are with black crap inside you will need to clean replace these lines and the canister. do not over fill gas tank then park the vehicle..or fill up the fuel tank and put in a heated garage.
Originally Posted by EllenH