Help with Engine Code P0453 Evap Emission System Pressure Sensor/Switch High

[RLK1962]

Hello,

 

My 98 Subaru Impreza Outback Sport threw the code P0440 Evaporative Emission System  back in November.  After some research I checked the gas filler pipe and found it to be corroded with holes.  I Replaced the filler pipe (and sensor near top of filler pipe).  A few days later check engine light came back on.  This time with engine code P0453 Evaporative Emission System Pressure Sensor/ Switch High. 

 

Car seems to run fine, but, if I let the fuel level get below 1/4 to 1/2 tank I will sometimes have trouble filling the tank at the gas pump.  For some reason when I start pumping gas it will "shoot" out the filler pipe (like the tank is full).  I know the tank is low on fuel, but, for some reason pressure is built up inside and will not take anymore gas.

 

Before I drop the tank wanted to see if anyone has experienced this code/problem and get some ideas of possible causes.

 

Thanks ahead of time for the help!

 

RLK1962

 

[Fairtax4me]

If the sensor at the top is the one with the two small hoses leading to it, you probably switched the hoses by accident.

That's a valve that controls air flow out of the tank and will prevent the tank from venting properly while refueling.

 

There are some other valves and hoses that go to the charcoal canister that can clog or stick open/closed and cause problems, but the valve at the top of the filler is a common issue after replacement of the filler. Swap the hoses and see if that fixes it.

[Mattndew76]

Don't forget to jog your keys in the ignition two to three times to prompt the solinoid to vent the pressure. Most modern cars need this. Mechanic demonstrated this for me.

[Fairtax4me]

Don't forget to jog your keys in the ignition two to three times to prompt the solinoid to vent the pressure. Most modern cars need this. Mechanic demonstrated this for me.

This is NOT normal, and is a temporary fix at best for a failing or stuck solenoid. Modern cars do not need help making the emissions control systems work. Something is wrong with the components of the system if cycling the key actually helps.

[Gloyale]

Don't forget to jog your keys in the ignition two to three times to prompt the solinoid to vent the pressure. Most modern cars need this. Mechanic demonstrated this for me.

 

?????

 

Not a normal thing to need to do for subaru.

[RLK1962]

**UPDATE** Tried switching tubbings to sensor at top of filler tube as suggested.  Still getting same engine code P0453 Evaporative Emission System Pressure Sensor/ Switch High.  Tank was down to 1/4 and tried filling (slowly).  Again, after taking a quart or so, gas began spilling out of filler tube like tank was full (even though it wasn't). 

 

How sensitive is the charcoal cannister?  Was thinking of dropping it down and blowing out tubings that connect but don't want to "damage" it.  Seems like i have a blockage somewhere.