P0457 not gas cap, purge valve?

210

Asked by Patrick Jan 24, 2019 at 02:48 AM about the 2008 Subaru Forester 2.5XT

Question type: Maintenance & Repair

This past Summer of 2018 just bought a 2008 Subaru Forester automatic,
2.5L Pzev with 116,000 miles.  Keep getting P0457 code when gas tank
goes below 1/4 tank.  Changed gas cap, no obvious loose hoses up top, but
still get coden.  Only getting 22mpg, not sure if this is normal.  Car hard to
start after full-tank refueling.  Could it be the purge valve solenoid?  Where is
located, easy access?  Any ideas would be great, thank you!

9 Answers

1,570

There are 2 valves on top of your gas tank. They are notorious for getting small cracks in them and setting this code. Even smoking the system it’s almost impossible to see the smoke because they are directly on top of the tank up against the body. If only one is cracked just replace them both because the other will crack very soon. You will have to drop the tank to replace them which requires removing exhaust, driveshaft, and lowering rear cratle. I suggest having a dealership do the repair for you. It isn’t cheap because it’s labor intense. The parts are inexpensive

13 people found this helpful.
210

Is this my Purge Valve solenoid behind the alternator?

6 people found this helpful.
1,570

Your purge control solenoid is what is pictured behind the alternator on the manifold. Have you checked the drain valve and canister assembly? It’s under the car. It’s mounted to the body, if you go to the fuel door facing the car it’s under the bumper about 6” to the left of where the fuel door is. In the diag tree from Subaru is this order -Check fuel filler cap ensure it is a Subaru OE inspect the rubber gasket around the threads. Is the cap secure -check drain valve -check purge control solenoid valve -check pressure control solenoid valve -check EVAP control system line -check Canister -check fuel tank roll over valves Photo attached is the canister assembly with drain valve as part of the unit. View is looking toward passenger rear tire from rear differential

15 people found this helpful.
1,570

The pressure control solenoid is mounted separately above the canister see photo

4 people found this helpful.
210

Having trouble figuring out from the diagram where the canister is located? I believe there is a "Vent Valve" on the charcoal canister underneath near rear of vehicle. Was thinking the "Purge Valve solenoid" might be the reason for hard starting when fill-up and the evap P0457 code. Thought changing Purge Valve might be first step, easier step before smoke test.

4 people found this helpful.
210

Have read that the drain valve on the canister in rear of car could be the cause of the issues I am having. Think to remove that valve, may have to replace the whole canister assembly, that is why I was going to try the Purge valve first if it was in an easy location. Thank you!

3 people found this helpful.
210

Okay, changed the Purge vent solenoid behind the alternator, this fixed my hard-starting after refueling, but did not fix the P0457 code. No apparent cracks in the charcoal canister or the hoses to it. If the Charcoal canister is bad, do I have to change the whole thing, or is the "drain valve" a part of the canister that can be removed? There are small clips on the charcoal canister where it seems like certain sections could be removed.

8 people found this helpful.
20

Hi everyone. Greetings from mexico I own an forester 2007 xsl I dont have any code, instead i have incompleted evap test cycle, AND that disable my Cruise control. ITS a kind of soft mil, that eventually appears when test cycle finish then just blinking Cruise light not check engine. AND in test mode appears, 0.020" leal, 0.040" leak, AND 0.090 leak un my car test I am pretty sure that drain Valve Is leaking. I disassembled AND checked, no dirt on diaphragm, AND proceed to replace orings Info about that Is value

2 people found this helpful.
20

I Will get spares AND i Will send result. Also i checked function for solenoid. It was good

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