I have a 2011 Ranger 4.0L from canada

My truck is throwing 2 codes, P0446 and P0453, both related to evap.
- Ive checked vapor canister -> not clogged
- Ive check vapor canister solenoid -> open and closes, fully
- Ive checked tube from gas tank to vapor canister -> also, not clogged

Here's what the code descriptions are:
P0446 - Evaporative System Vent Control Circuit Malfunction
P0453 - Evaporative Control System Pressure Sensor High Input

Ive erased the codes, but 2 remained, even if CEL was off, could this be why the codes always comeback? If not, HELP im flat out ion ideas

 

EVAP system codes take awhile to clear, up to 5 drive cycles, 5 warm up cool downs.

The computer runs a self check when truck is off, you can't force it to do it, it just does it when it feels like it, lol.
Best thing to do for now is to never left the tank get below 1/4, and don't fill it up, just fill it to 3/4.
Do this for next 5 drive cycles and see if CEL comes on.

 

Thanks RonD. I have tried, the truck has failed :P

Reset the CEL last night, started the truck only this morning and no light HOORAY!, I had to make a stop on the way to work; when I fired 'er up again, the CEL was back :'(

 

OK, then
P0446 is most common when fuel cap is off or not sealing tank
The Computer closes the vent solenoid then tests if tank can hold vacuum
If tank's pressure sensor say "no" then computer sets P0446

P0453 is the code for tank's pressure sensor voltage being out of range.
This could be a bad sensor or shorted wires, and it would also cause P0446 because test couldn't be completed.

Tank's pressure sensor is on top of the tank, but you can test the sensor:
Remove the gas cap(to remove any pressure in the tank), and turn on the key, with the OBD II reader hooked up use live scan to check the voltage of the Fuel tank pressure sensor, should be about 2.5v with gas cap off.
If it is then problem is not the sensor, if it is above 4v then could be wires or bad sensor, you will need to access sensors connector to find out which

 

Swet! Ill check that out this week-end. I've should have easy acces to that sensor, given that I got a 3'' body lift :P

 

check the filler tube and make sure the clamps are tight. look for any kind of dampness around the filler near the box and the tank. my explorer is throwing a code for evap cause my filler neck is rotted at the clamp at the top. maybe somthing came loose during the lift procedure.

 

Do you know where I can purchase this sensor, for under 300$

 

I would first see if the connector is OK.
I would check what years and models use the same sensor, then..........hit the wrecking yards for a replacement.

They would most likely use the same sensor on cars or trucks

 

im going to try this on the weekend thank you for sharing a simple test :)

 

I was throwing the same 2 codes on my 2007 4.0 ranger, I found the sensor located on the frame rail inline between the tank and canister was unplugged. plugged it in and p0453 has cleared but p0446 remains. Also repaired broken wires found by the front drive shaft. Now I have another issue. The tank never seems to vent, after a ride there is so much negative pressure that it just about sucks the fuel cap out of your hand when removing. I felt the valve at the canister and it was hot, it has 12 volts and closes as soon as the connector is plugged in. It is new and was replaced by previous owner. Obviously something is telling it to close. I am not sure what tho or how to track that down. I am not sure if the sensor on the frame rail is the Fuel tank pressure sensor and maybe that's at fault? Any help?

 

Fuel tank pressure sensor is on the top of the gas tank

There should be negative pressure in the tank for 5 to 10min after shutting off the engine, yes can be quite strong, usually only noticed when stopping for gas

 

Thank you Ron, I was hopping you would respond. Should the negative pressure be present even when the vehicle is running? I haven't had any luck getting that p0446 to clear. Would you know what that sensor on the frame rail is and what it does? I look at the top of the tank when bed was off and aside from the sender connection I did not see any other electrical connections.

 

Yes, should have highest negative pressure when engine is running and when driving, point of the EVAP system is to suck gas fumes out of the tank as the gas sloshes around, and burn said fumes in the engine via the vacuum pulling fumes from canister to intake

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

The computer(PCM) runs the system
3 wire pressure sensor on the gas tank
2 wire solenoid for Canister vent
2 wire solenoid for Purge valve, on the engine

The PCM opens purge valve, and uses engine vacuum to suck air from the charcoal canister
The Canister Vent solenoid should be off now, closed
Air is then sucked out of the gas tank and thru the charcoal canister to the purge valve and then into the intake to be burned

When you shut off the engine the computer closes the purge valve, but doesn't open the canister vent valve, so negative pressure is trapped in the tank

The 2 solenoids should get 12volts with key on, solenoids GROUND is controlled by PCM
So with key on the PCM should "see" 12volts passing thru each solenoid on each of the 2 ground wires, if not it will set a "circuit code" for that solenoid

Solenoid valves are CLOSED with no 12v or ground, so normal state is CLOSED
12v and ground are applied to open a solenoid

So with key off both should be closed

P0446 Evaporative Emission Control System Vent Control Circuit Malfunction
Could mean PCM is not "see" 12volts on its ground wire for the the canister vent solenoid

Key on(12v)-------------------------------solenoid--------------------------PCM(sees the 12v)

A solenoid(or relay) is just a coil of wire around a metal core, so 12v in = 12v out
If you ground the coil of wire then the metal core becomes a magnet, this would OPEN the valve(or close a relay)

PCM also uses PWM(pulse width modulation) on solenoids, it can Pulse the Ground, which is the same as lowering the Voltage, so using PWM it can hold a solenoid valve, 1/4 open, 1/2 open, 3/4 open, pretty much any open setting it likes
It uses the Pressure sensor on the top of the tank and PWM on Purge solenoid and Vent solenoid to set pressure and to see if it holds or drops when it shouldn't
i.e. P0442 Evaporative Emission Control System Leak Detected (small leak)
or P0455 Evaporative Emission Control System Leak Detected (gross leak)