I just bought a used 2002 Chrysler T&C. After a week of driving I got the cel code P0455. I have read tons of threads about this and it seems to be a common issue. What I am wondering is if this would have an affect on gas mileage? I don't see how it could be we are only getting 13 MPG which seems really low. We typically let the tank run down below 1/4 before we fill it. Doing this we were right around 13 MPG each time. Last time I filled it up at about 3/4 tank and got 18 MPG. This doesn't make any sense. I have read a possible problem that would create code P0455 is a rusted filler neck. Would this or anything else that would cause the P0455 code impact gas mileage in this way? It may have just been a fluke to get 18 MPG. The 13 MPG was pretty common over the last 5 fill ups. Any help would be greatly appreciated.

Ray

 

Well 1st off, what does P0455 translate to? Do you reset the MPG everytime you fill up? Do you have auto climate control? Also.. have you hand calculated the mileage? I am assuming here you are going by the overhead computer which can be off but usually on the high side.

In our Pacifica and T&C around town we can get the 13's if we use that darn auto climate control which seems to use the A/C compressor even when it does not need to. We typically get 15+ in both vehicles if we control the temp on our own for around town driving. On the highway these vehilces get 21 (van) to 24 (pacifica) mpg but we don't drive over 70 to get these freeway miles.

 

P0455 is a large EVAP leak. Check all the hoses and connections to insure that all are tight and not cracked. I do not know for certain if it could effect mileage, but guess I would not be surprised if it did. 454 is right, the overheads can vary quite a bit, I come to expect about 10% on my Aspen and about the same on my Durango. Best bet is to calculate it to see what you are really running.

 

I hade the same code proble and replace the filler neck (was so rust, my God) problem solved, lights go off

 

The most frequent cause of a P0455 code (large leak in evap system) is probably a faulty or improperly secured gas cap. To the extent that you may be evaporating gas into the atmosphere, your gas mileage will decrease as a result. It shouldn't be that big an effect, I wouldn't think.