Had service engine soon light on this morning. Pulled code P0455. Figured it might be gas cap. Confirmed cap was snug and I cleared the code to see if it will come back on. Went to fill vehicle with gas and when it was full fuel began to spill from under the vehicle. Fuel gauge says full and there is no active leak when it’s parked and off. Any thoughts?

2008 Nissan Pathfinder
5.6L V8

Thanks,
Ty

Define “full fuel”. If you don’t have the gas supply nozzle all the way inserted, or you keep squirting those last drops in, you overfill the filler pipe and gas will go down the vent tube.

Normally that gas will go into the charcoal canister and wreck havok with the filter elements in there, but if you have a stuck solenoid the liquid gas can go out the purge valve.

Of course, you might have a rusted through filler pipe which also would give you the leak/code.

Smoke test revealed a leak on the top side of the fuel tank. Lowered it down and the fuel pump was actually sitting a half inch above the locking mechanism. No work has been done on the fuel system since I’ve owned it. Pressure in the tank was high. Maybe the pressure built so much it popped the pump out of place. Purge valve seems like the likely culprit to me. Replaced the purge valve and I’ll see what happens the next couple of days.

I had an overpressure situation in my gas tank. It turned out to be the vent drain clogged with debris.