Greetings, please forgive this longwinded story. On a recent 1000 mile trip in my 96 850, I noticed during a gas fill up, that after I was done, I had gas dripping pretty heavily from under the car, from the top of the gas tank where the fill pipe connects to the tank. It dripped for a few minutes, then tapered off. I chalked it up to overfilling up into the neck, and coming out an overflow valve on the tank.

A couple hundred miles later, the check engine light comes on, the readout on my generic OBD II scanner reading P0440, EVAP emission control failure. Some others on this board have also reported that as error 315 on Volvo scanners I think.

I've read about filling the charcoal canister with liquid and triggering these codes when you religiously overfill, but after several code resets, and several tanks later, the light keeps coming back. I've made sure to stop overfilling by the way. If I had gotten liquid into that canister, would gas have come out from the rear tank area? I'm not sure where the canister is located. Can I inspect it for liquid?

I need to pass a state inspection in the next few weeks, so I've got some questions. First, what constitutes a "drive cycle" with these Volvos? Is an entire drive cycle required to get the "ready" status for all OBD II systems?

Second, any theories about the overflow dripping incident and how it might relate to my recurring error code? I've been pouring over previous posts, and haven't found a story with these codes that quite fits my circumstances.

Thanks for any help everyone!