When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hey everyone! My 2007 2.3L gave a code P0446 : Evaporative Emission System Vent Control Circuit. First thing I did was buy a new vent solenoid, since it was cheap and easy enough to pop in.
Check enging light came back on after being reset, so I got underneath to test the solenoid as past threads suggested. The solenoid works (properly closes) when tested with a 9V battery, but does not when plugged into the truck's wiring with the key turned on. (I can still blow through the solenoid with the key on, so it doesn't appear to be closing).
So that means power isn't getting back there... What should my next step be?
Fuse 21 in engine bay fuse box, 10amp, supplies 12volts to Vent valve all the time, it is also use for "Keep Alive Power"(KAPWR) for computers memory
So if you don't have 12volts on the grey/red wire at the Vent Valve then fuse is blown or wire is damaged, again this is not key on power, it should have 12v anytime battery is connected
The Green/blue wire at the Vent valve is the Ground supplied by computer to open or close the Vent, and its also how the computer "knows" there is a Circuit Malfunction(P0446)
With key on computer boots up
The Vent valve is a solenoid so is just a coil of wire around a metal core that becomes a magnet with 12v and Ground, so 12v IN = 12v OUT
After boot up the computer should see the 12volts on pin 13(green/blue wire) as the 12v passes thru the Vent valve's coil from the grey/red wire
If not then P0446, which means no 12v at pin 13
It could be the green/blue wire is bad, so test if you have 12v on the grey/red wire at Vent valve first, if so then problem is the green/blue wire
Wow, thanks for this super helpful response. Fuse 21 did not appear blown, so I tested the wires- red/gray had no voltage, so I traced it back, and sure enough I found this at one of the connections:
Do I have to buy some sort of wiring kit? Could I solder?
There are several type of connectors and so several Video how-tos on doing each kind, but not hard at all
You may be able to solder it but probably need to remove the pin to do it or you will melt connector so even more issues, lol
You can buy new pins that crimp on to the wire as well but have to buy 25 to 50 at a time
Wrecking yard might be a place you could cut out connector with similar pins but with extra bit of wire attached to pin so you could solder that to current wire and insert pin into connector
Take lots of pictures in case other wires in connector accidentally come out, ask me how I know "now" to do that, lol
Fuse 21 in engine bay fuse box, 10amp, supplies 12volts to Vent valve all the time, it is also use for "Keep Alive Power"(KAPWR) for computers memory
So if you don't have 12volts on the grey/red wire at the Vent Valve then fuse is blown or wire is damaged, again this is not key on power, it should have 12v anytime battery is connected
The Green/blue wire at the Vent valve is the Ground supplied by computer to open or close the Vent, and its also how the computer "knows" there is a Circuit Malfunction(P0446)
With key on computer boots up
The Vent valve is a solenoid so is just a coil of wire around a metal core that becomes a magnet with 12v and Ground, so 12v IN = 12v OUT
After boot up the computer should see the 12volts on pin 13(green/blue wire) as the 12v passes thru the Vent valve's coil from the grey/red wire
If not then P0446, which means no 12v at pin 13
It could be the green/blue wire is bad, so test if you have 12v on the grey/red wire at Vent valve first, if so then problem is the green/blue wire
Diagram below
-nvm-
Last edited by Daniel105047; Dec 26, 2025 at 07:22 PM.
Reason: Delete
