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P0446 code

i have a code p0446 for evap solenoid which is the solenoid mounted on the intake. does the code mean something is wrong with the solenoid itself or does the system see a less than expected vacuum reading in hose and throw the code for the solenoid itself? if there was a leak like a bad gas cap seal would i still get the code 0446? parts store said intake evap solenoid. there is a 2nd solenoid on the charcoal cannister near the gas tank. i changed both of these solenoids and still have the code after clearing system

Yes. The ECU can’t determine WHAT the problem is, just that it IS. I had this on my truck. Replaced gas cap, no change. Had the valve replaced on the engine. The code came back weeks later. Turned out ti be the pressure sensor in the tank.

From the Web:

Possible causes

  • Missing Fuel cap
  • Incorrect fuel filler cap used
  • Fuel filler cap remains open or fails to close
  • Foreign matter caught in fuel filler cap
  • Vent control valve harness is open or shorted
  • Vent control valve circuit poor electrical connection
  • Faulty vent control valve

All relate to an error in pressure readings. Any can cause the error.

Yes Sir… Mustang man nailed it here. A faulty tank pressure sensor? Man that sucks…

So…my advice is to read Mustang mans advice. That 446 code can be a pain in the ass because it actually doesnt ID any specific part…its more of a comment on the interaction between parts if that makes any sense.

OK…I’m not really helping here am I ? Sorry

sensor is on top of fuel pump assy? code is for solenoid. not the pressure sensor. so sensor is good but system does not like the pressure reading? so, the charcoal cannister has a solenoid. the intake manifold has a solenoid. and the gas tank has a pressure sensor. and its 90% probable that i have a cracked hose or fitting somewhere? its an 06 equinox

Actually it was pretty easy, I’d make my own access panel to replace the fuel pump already. Took all of 10 minutes! Darn glad I cut the hole, taking the tank out is a real pain!

LOL…Yeah dropping tanks was never my fav thing to have to do…for any reason. Anyway, I thought i was the only idiot er I mean creative person who dared these things.

No access port for the fuel pump should be a punishable crime in my opinion… I’m sure you know what I mean

How do you know this? Actually, you don’t and neither does the ECU. A bad sensor is a possible problem.

Mustang is correct (as usual) that 446 code doesnt point to a specific item… but a symptom within a system.


You can test the purge solenoid and vent valve by removing them and applying 12 volts and ground. You should hear the solenoid click, and you should be able to blow air through them when they’re open, and should not be able to blow air through them when closed. If I remember correctly, the purge valve is open when powered, and the vent valve is closed when power applied. Someone can correct me if I’m wrong.

I went through an evap system problem with my 05 Sierra. I had a different code though for a gross evap leak (P0455?, don’t recall for sure). I determined the purge valve solenoid was failed open. I replaced it with a Duralast “lifetime warranty” part (my bad), and the check engine light came on again in a few weeks. Upon testing with 12 volts like I mentioned earlier, the new sensor had failed. I replaced with oem and it’s been fine now for months.

Also, I was also able to take the charcoal canister apart and clean and inspect it. I’m not sure if this can be done on OP’s model. I also blew air through the lines with the solenoid and vent valve removed to make sure there were no obstructions. I used human air, not compressed :laughing:. Good luck.

i removed cannister near gas tank to check it. much is said online about symptoms like slow gas filling which i have. it was clean inside. the inlet hose from gas tank goes thru a square 2x2" rect box that has a silicone seal that i found was partially missing so i filled joint with silicone. is it still leaking? store said my manifold solenoid was issue and i got a boneyard one and both are 190ohms but i did not test them with 12v to see if they click. inlet hose seems closed on both.

Never listen to the store :stuck_out_tongue_winking_eye:. They told me fuel system cleaner might fix my gross evap leak code. Huh?

I would check the boneyard solenoid (and purge solenoid) with 12 volts while blowing through the hoses. Make sure they’re completely opening and closing. Entirely possible the boneyard unit is bad. It’s a pretty common failure, and generally causes nothing more than a cel. Lots of people ignore the light. Especially on a vehicle headed to the boneyard. The vent valve solenoid may be failed shut. Would explain the code and the difficulty adding fuel.