So I'm getting a cel code p0446 system vent control valve. I have one of the elm things with forscan and it's saying it can't complete the initial check and that it's likely a wire problem. I've checked everything and replaced the canister, the solenoid, and the purge valve with no help. My cap is new also. I took my bed off today for a better look because it's running like **** and getting BAD mileage. It's jerking at low rpms but only when in gear. I've also noticed it's shifting alot smoother which is weird. It's always shifted a little rough especially with the pedal on the floor. Any help would be greatly appreciated guys... Thanks

 

EVAP system diagram here: https://www.motor.com/wp-content/uploads/evap1_0317.png

P0446 EVAP System Vent Control Circuit Malfunction

Yes, possibly a wiring issue for the Vent valve which is on the charcoal canister as seen in diagram, in a 1995 and up Ranger that should be behind the gas tank

Find it and check its wires, follow them as much as you can
It would be helpful to know the year of the Ranger?

 

It's a 2007. I've replaced the valve or whatever at the canister and I don't see any wire issues. I currently have the bed off it. I've replaced about everything... So idk where to go other than a car lot and trade it in on something else. I live off this truck and need to be able to rely on it...

 

Since I took the bed off now I'm getting a p0232 p0316 and the p0446 and p1000. FYI guys...

 

Disregard the last cel post only p0446 and p1000 now

 

P1000 just means computer has been reset, or fuse 21 in engine fuse box is blown, see below

Below diagram shows wires to Vent valve
Grey/red wire should have 12volts all the time from fuse 21 in ENGINE fuse box
The other wire, green/blue, runs to the computer and should also have 12volts at the computer end when plugged into vent valve

Vent valve is just a solenoid, so a coil of wire around a metal core, so 12v IN and 12v OUT, the computer would Ground its wire to activate solenoid, but would "see" the 12volts when it wasn't grounded, and thats what sets Code P0446, no 12volts at the computer end of the circuit

Fuse 21(full time 12v)-----------(grey/red)-----------------Vent Valve----------------------(green/blue)------------------------------pin 13(computer)

2007 will have 3 computer connectors, C175B pin 13 would have the green/blue wire
Diagram of that connector here: https://photos.smugmug.com/Public-Ph...75B-conn-L.jpg

If you have 12v at pin 13 on C175B(vent valve plugged in) then Computer is the problem, which does happen, and would explain any other engine running issues, because P0446 wouldn't effect engine operations, but a faulty computer would
If you don't have 12v at pin 13 then that wire is broken

I use a sewing needle to pierce wires to read voltage or ohms, it won't hurt the wire, you can also get Volt/Ohm meter probes with "needle" ends to pierce wire the same way

 

You're the greatest I'm checking now and I'll get back and update ya. Thanks alot that makes so much more sense now...😁

 

Ok so here's where I'm at... I checked all the wires and such and unplugged the pcm hunting for damaged wire. While doing this, I checked the wire at the solenoid and it had 12v to it!! I plugged everything back up and started it, no CEL... Imagine my joy!!! Only to restart truck later and see that stupid *** light again. It did this last night when I unplugged and reconnected it in the dark. I hope it's not the pcm.. but I have a junk 07 if they are interchangeable... What do y'all think??

 

No, not interchangeable as far as just the PCM
You would need to swap instrument cluster(PATS) along with its matched PCM, and then swap the ignition key cylinder so you could use the transponder key that matches the new clusters

2004-2011 Rangers had PATS "module" in the new Digital Instrument cluster(HEC)
These HEC clusters are "married" to the PCM at the factory so people can't swap in lower mile odometers to scam buyers
So with key on the PATS test for correct key is done, and PCM and HEC "handshake" to make sure there were no changes, then PATS "tells" PCM "its OK to START"

If there is a Local Ford Dealer you can call and give them your VIN, they can look up any service updates for the PCM regarding that code
Also ask how much to swap in a PCM that you already have, they will have the software to match "new" PCM to old HEC, "marry" them, like at the factory, they won't guaranty it will solve the problem, so its a "no warranty" repair

You can look over at the Forscan forum
Forscan is a software that can "talk" to Ford PCMs via the OBD2 port, I had read that you can "sync" new PCM or HEC using this software, its not expensive, but need a laptop and the OBD2 to USB cable for hook up

 

I actually have the forscan software setup although I'm not completely literate with it. That and The Ranger Forum is how I've gotten to the thought of having a broken wire going to the solenoid at the canister. But it's starting to make less sense. I swear it seems like I get 1 step ahead or get something figured out and something else completely irrelevant screws up. I'm beyond tired of chasing this issue.🤬🤬🤬🤬😡😤

 

Here is what I found when I took the computer and electrical tape off the wires to the computer...

looks like somebody has had ahold of some of these for whatever reason... Sheesh...

 

Surely this isn't supposed to be like this... How do I even fix this horse ****???😡


the 2 wires coming out of this "connection" go to the ground stud...

 

Yes, looks like some non-factory changes were made, but...................I have never unwrapped a 3 plug PCM wiring harness, so maybe that passes as Factory job

 

Good God I hope not. It was definitely tape tho. I really don't even know where to start to try and fix this. The forscan thing on my laptop was saying it's likely a ground issue and this by far makes the most sense of what I've found. So idk I may just replace what I can as properly as I can and go from there...

 

Well the 12volt wire at the Vent Valve tested as OK with key on, so yes, it would be a Ground issue, the "other" wire at the Vent Valve is the ground wire, controlled by the computer
Can't remember if you ever tested the vent valve, you can test it with 9v battery, or 12v and ground to make sure it "clicks" open and closed, no polarity, as long as it has + and - it should "click"

 

I test both of them like that right?? The one at the canister and under the hood correct? I went ahead and got a nicer multi meter rather than the 3 dollar one from harbor freight lol

 

I've also noticed the other OBD2 reader says there's like 5 other monitors that aren't reading now. Like the hcat egr etcWtf???

 

That reads like a fuse issue, check fuse 43 in engine bay fuse box, 20amp, may have blown because of testing

 

So all my fuses are good. I've recently noticed it keeps getting a cylinder 2 misfire. So I change the plug and it helps but goes back to bucking at low rpms within a week. So I did some random reading on that issue with the 13 mpg and sensors not being ready and decided to change the forward o2 sensor and plugs, wires, and coil pack. Finally a vast improvement!! It will actually downshift when you stand on it now!! Oh and one other thing is on the forscan thing is I can bring up the evap testing commands and physically force one if the solenoids to go to closing and it starts to run like **** and die. I don't feel I know enough about the live data or the 5 volt reference to be able to pinpoint an issue. However it IS running much better but still have the cel. Any suggestions??