ODB II code P0440
 

I have a 2000 chevy blazer 4.6 l 2door 4x2 with 98K on it, and I need some help here. I'm not a mechanic genius, but can usually figure things out with help from the web. I'm getting a check engine light on my dash....i've already read the diagnostic chart https://blazerforum.com/forum/diagno...plained-35145/ although I'm a bit unfamilar with the evap emissions system. I've already replaced the gas cap, and while I thought that fixed it, it tripped the same code and dash light after 4 days of not doing that.

Anyone know what the likely issue is? Even though I realize all cars are different, and any variance of issues can happen case by case, I was hoping someone could tell me if something common happens with my year of blazer. If you have some info, and could tell me where the line or part is on my vehicle to look at, I'd highly appreciate your help.

Thanks in advance!!!

No idea if this will apply to you, but I believe that the it can also be set off by a clogged EVAP canister or tube. I had the exact same situation, where I set the code, replaced my gas cap and cleared it, but the code kept coming back. I tried everything including pulling and cleaning the box up above the spare tire (can't remember what its called), thinking I may have gotten water in it crossing a stream. None of those seemed to work. One day I was in a field and was spinning my tires pretty good in some mud (ie, high RPM) and the CEL went off, the code was gone and never came back. Going on 3 years now. I think I may have just had a clogged EVAP tube that somehow cleared or cleaned out.

I can't say that will help your situation but its my unscientific, non-mechanic 2 cents worth.

good thought
 

I've done some research and they've referenced checking this EVAP canister out for a possible clog. Any idea how I can get to this canister/tube? Someone told me they thought it was somewhere near the fuel tank? Any insight would help huge:icon_exclaim: I think this canister is worth a try.

The charcoal canister is a box behind the fender, outside the frame, behind the rear tire. There is a tube from there leading up to a box mounted on the frame up above the rear axle. When I worked on mine I unbolted the box up above the axle, disassembled it and cleaned it well. It has a foam filter that is to keep debris and dust from entering the system, and it can get clogged if it gets wet or too dirty. Cleaning this didn't immediatly fix my P0440 code, but it was a couple days after doing this, and then while reving the engine & spinning my tires that the CEL went off.

I personally didn't do anything to the charcoal canister, so I can't say how serviceable it is.

I'm tackling the evap. canister right now and can't figure out how to get the fuel lines off.

Check the condition of the filler neck assembly as well; these are prone to rust through and will trigger a p0440. This happened on my 97.