2007 ranger 4.0 p0446 evap issues

[broncoll]

Hi all,
I have recently acquired a 2007 ford ranger with the 4.0 4x4 and a 5 speed manual. Previous owner was having issues tracking down some evap problem codes. He replaced the vent valve on canister, pressure feed back sensor, tps sensor, gas cap, and purge valve. I got it with codes p0453 and p0446. Pulled the bed and started to dig in. Found the sensor located on the frame rail between canister and tank was not connected properly. I believe this is the fuel tank pressure sensor but have not been able to confirm the name of it so please correct me if I am wrong. I also found two wires worn bare up by the front drive shaft. repaired those and connected fuel tank pressure sensor code p0453 cleared. P0446 still remains, I have confirmed the vent valve has 12v going to it, it opens and closes. What I have noticed now is that the tank builds so much negative pressure that when removing cap it about sucks it out of your hand. Also fueling was an issue taking 20 minutes for 20 dollars. I found that the vent valve was hot, I unplugged it and negative pressure as well as fueling is no longer an issue. It is staying closed all the time and unsure why. Does anyone know what tells the computer to open that valve? I suspect its the fuel tank pressure sensor located on the frame rail but I am not even sure if that is what that part actually is. Any help is really appreciated I for sure thought I hit a home run finding those bare wires. I need to get this truck inspected asap.

 

[RonD]

For the slow filling issue

Filler for 2007 Ranger: https://www.fillernecksupply.com/2006-2007-2008-2009-2010-2011-ford-ranger-fuel-filler-neck-pipe-tube-4l5z9034a/

See if this is what you have, just look up under the bed fender, Ford used two types

The smaller tube is the tank Vent that lets air out while you fill the tank using the larger tube
Not part of EVAP system just allows air out as gas flows in
If you look at the opening under gas cap you should see OPEN vent holes around the larger filler tube, and should feel air coming out as you fill up
If you don't feel the air coming out when filling the tank then vent is plugged somewhere, can be a kinked rubber hose on top if the tank
There is a separate Vent Hose connection on top of the tank, with "float valve" to prevent fuel from flowing OUT when tank is full


There should be negative pressure in the gas tank just after engine shut down, and quite a bit for 5 to 10min
So usually only noticed when stopping to fill the tank

There is a pressure sensor on the top of the tank, it tells computer how much negative pressure is in the tank and if tank is leaking pressure as well
So if there was too much pressure you would get a different code for that

Code list here: https://www.therangerstation.com/tech/obd-ii_trouble_codes/
Best to look up codes on a full list not just Google the one code
Computer has several codes to chose from for EACH sensor or control
So the ones it DOES NOT choose can mean as much as the one it does choose

EVAP codes are a pain to diagnose, lol, as you have found

Heads up
"New" does not mean what it used to, new just means NEVER EVER TESTED now-a-days, not "it works"
You get a warranty now, which means "YOU test it, and we will replace it if YOU find it doesn't work", this is much cheaper than Quality Control, i.e. testing parts before boxing and shipping

Ford(Or GM) Parts are way more expensive, because they are tested, car makers still require it because in the long run its cheaper to pay more for a tested part than to replace a cheaper part in the field, under warranty

 

[broncoll]

Sorry for the delayed response, below are my findings.
I was able to borrow a snap om scanner from a friend to command the canister solenoid on/off
Connected a noid light to solenoid plug and found that when turned on with the scanner light would illuminate but when turns off the light would dim slightly but not go completely out.
Located pin 13 on the pcm and tested from pcm directly even when commanded off I would still have ground on wire from pin 13.
Previously I found worn wires near front driveshaft one of wich is the blue and green so my suspicion is that somehow it has shorted to ground internally on the pcm.
I know with this year the pcm is "married" to the dash among other things. I found a company online that has a pcm and claims to send it preprogrammed to the current Vin. Not sure how legit that is but unless anyone knows better I may take the gamble rather than having my truck tied up at the dealership for who knows how long and a costly bill at the end.

 

[RonD]

May have to do that any way if PCM doesn't work with Cluster, odometer in PCM needs to match odometer in Cluster as well as doing correct "handshake" with key on
VIN doesn't have odometer reading, lol, so they probably can't do it

 

[broncoll]

That's kinda what a fear. Too good to be true type of thing lol. I guess I'll call the dealer tomorrow and see if I can get a quote. To you does it sound like it's the pcm being the issue? I isolated the circuit by testing right at pin 13 so to be I can't see it being anything else.

 

[RonD]

Well these type of solenoid circuits are hard to test because with key on the PCM checks for the 12v at the solenoid by reading 12v on the GROUND wire, in this case at pin 13
If it doesn't "see" the 12volts passing thru the solenoid it will set a Circuit Malfunction code
So pin 13 is not "a ground" like an on/off thing, its an internal circuit(PCM) to monitor that one solenoids wires and function
Each solenoid will have this type of circuit on its control ground wire connection to PCM

P0446 Evaporative Emission Control System Vent Control Circuit Malfunction
P0447 Evaporative Emission Control System Vent Control Circuit Open
P0448 Evaporative Emission Control System Vent Control Circuit Shorted


Not OPEN(so pin 13 has 12v with key on) and not SHORTED, is all P0446 tells you, lol

 

[broncoll]

Well Ron, I thank you for all of your information. After all the testing I was pretty confident it was the pcm. After replacing it my evap codes cleared and monitor completed. However now I have a p0420 and p0430. I'm assuming maybe this monitor never had a chance to complete due to the evap issue? Surely am stumped. I didnt have those cat codes with the old computer but now I do. Very strange.

 

[RonD]

P0420 Catalyst System Efficiency Below Threshold (Bank 1)
P0430 Catalyst System Efficiency Below Threshold (Bank 2)

These are downstream O2 codes on a V6/V8 engine

After engine is warmed up check the voltage on these O2s, should be fairly steady and 0.75-0.85v