Code P0446 evap system electrical circuit

[Joserh12]

Check engine light on my 2015 Sierra 1500 came on today giving a P0446 evaporative emission system vent control electrical circuit code, and was trying to decide what’s the best way to go about it before buying any parts. Should I take it to the dealer or just any mechanic? Heard it’s a pretty common issue but not sure where to start or how to test anything. 

[durandetto]

Most common failure is the vent valve itself and the part probably costs less than the diag charge. If you know someone with a bi-directional scanner you can command it open and closed. If it makes noise more than likely it's fine. If not you need to check for power and ground at the solenoid while switching it. If no noise and good power and ground replace it.

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[bigoilman]

Before you get into it any deeper, make sure the gas cap is on tightly. Drive it a few times. If it doesn't clear, buy a new gas cap (they're cheap).

Edited April 6, 2020 by bigoilman

[lovecars]

Yes, Gas Cap

[tlaw91]

Gas caps have nothing to do with that that DTC.

Needs updated/rerouted EVAP CVS valve

It probably got junk in it, bad location from factory.

 

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[KWD2]

Just had this code come up today I cleared it with my scanner to see if it comes back on.  then going to try to tighten gas cap if not will replace canister they are not too expensive and the on the purge if it remains on 

[el_er1c]

3 hours ago, KWD2 said:

Just had this code come up today I cleared it with my scanner to see if it comes back on.  then going to try to tighten gas cap if not will replace canister they are not too expensive and the on the purge if it remains on 

Mine came on a few days ago and have been debating on taking it to a shop or trying something myself. Let me know it goes for you.

[KWD2]

On 12/17/2020 at 5:35 PM, el_er1c said:

Mine came on a few days ago and have been debating on taking it to a shop or trying something myself. Let me know it goes for you.

Actually it stayed off after i cleared it going see if it comes back on. Bought a $30 obd2 reader that will reset codes a few years back and has been worth every penny

[el_er1c]

15 minutes ago, KWD2 said:

Actually it stayed off after i cleared it going see if it comes back on. Bought a $30 obd2 reader that will reset codes a few years back and has been worth every penny

Thanks for the reply. The my check engine light started flashing today and the truck started shaking so going to take it to a shop tomorrow AM. 

[KWD2]

6 minutes ago, el_er1c said:

Thanks for the reply. The my check engine light started flashing today and the truck started shaking so going to take it to a shop tomorrow AM. 

Flashing is bad did you have the codes read?  sounds like you have more than a p0446 

[el_er1c]

2 hours ago, KWD2 said:

Flashing is bad did you have the codes read?  sounds like you have more than a p0446 

Only P0446 when I had it read so the others must have happened after. Doesn’t sound too exciting. Lol

[KWD2]

14 hours ago, el_er1c said:

Only P0446 when I had it read so the others must have happened after. Doesn’t sound too exciting. Lol

I had this happen in one of my gm's twice with the flashing and shuttering.  One time it was a bad coil pack the second time the cat conv went bad and clogged up the exhaust.  If it is a coil pack or spark plug it is not too bad on cost    

[el_er1c]

48 minutes ago, KWD2 said:

I had this happen in one of my gm's twice with the flashing and shuttering.  One time it was a bad coil pack the second time the cat conv went bad and clogged up the exhaust.  If it is a coil pack or spark plug it is not too bad on cost    

Took it to the shop this morning. The mechanic says cylinder 6 is misfiring so hoping it’s just the spark plug and/or coil pack. I’d hate to replace the cat converter 

[KWD2]

8 hours ago, el_er1c said:

Took it to the shop this morning. The mechanic says cylinder 6 is misfiring so hoping it’s just the spark plug and/or coil pack. I’d hate to replace the cat converter 

I'm glad to hear it is something cheaper