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!

Given the lack of evidence for a broken evap line on the gas tank, I've thought about the evap solenoid valve near the front of the engine compartment. Mine appears to be clicking and working while the car is running, but can these valves still go bad and trigger that P0440 error message? Is there another component in the evap system that can fail as well? I've already check the seal of my gas cap, it seems to be fine.

Any ideas?

I had a similar problem with my 96 850. Appeared as if the leak was coming from the filler neck. But it wasn't. had to drop the tank and found a small (mabye 6-8") rubber hose on the top of the tank that was split. I don't know the code that it threw, but it eventually did.

Good luck!

There is a vent hose for the tank in the same location. sounds like it cracked and needs to be replaced. That will also keep the tank from being pressurized and trigger the code.

Klaus
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The 164 has a new home, all I am left with are a 95 854T and a 98 V70R :)

Both problems are the same. You have a broken evap line off of the filler neck.

...Lee

Ozark, do you think that evap line is connected to the filler via one of those rubber elbows that always crack and break on 850's?

Is there a way to get to that without dropping the gas tank?

>>Is there a way to get to that without dropping the gas tank? <<

I'm not sure, do you have a wagon or a sedan? Let me know and I will look it up in VADIS for you. It also helps to know if it is a turbo or not and what transmission you have.

...Lee

Thanks for your willingness to help Lee. The car is a non-turbo wagon with a manual transmission.

It looks like you can. VADIS shows the line having its connection point directly above the fuel filter. You may need to remove the rollover valve from the frame to gain access to it.

...Lee

Forgive the simplicity of my question. I've gotten to the top of the tank from inside the car in my old 245, but never in my 850. I presume it's the same? Carpet/wood panels off, and some screwed in metal access cover that allows access to the fuel filter, evap line, and in tank pump wiring?

Actually, you get to it from the bottom. Once you get the rear on jack stands you need to locate the fuel filter which is mounted to the frame rail just in front of the tank. The rollover valve should be bolted to the rail next to it. It you look above the rollover valve and the filter you should see the evap line.

There are two access caps, under the carpet, behind the rear seat but those are access to the fuel pump and the fuel level sender.

...Lee

Lee, I've had a chance to do a thorough search for cracked evap lines. I located the fuel filter and rollover valve, and managed to trace the evap line up to the top of the tank, but it disappears very quickly between the top of the tank and car chasis. I didn't see any cracked lines or elbow in the lines I could get to.

I removed both access caps under the carpet and did some line tracing there as well. I found where several of them go into the tank through a rubber elbow, but everything looked in good shape. One of the elbows even looked like it had been replaced at one point; soft and supple rubber all around.

If there was a leak through those lines, it had to come from the top of the tank, because I saw it initially dribble out down the right rear of the tank, where that natural valley in the tank top funnels overflow. However, the top of the tank looks bone dry. I'm beginning to think the overflow I saw was a one time, too much top off deal, and was coming from the fill cap space, and not the tank.

At any rate, the error code still fires, and without evap line cracks, I'm out of ideas. Anything else come to mind?

Lee, thanks so much for the prompt information, its exactly what I needed to make this a quick and easy fix. Given the evidence, I'm almost positive that line is cracked, or off, and thats what firing the code.

Brickboard is amazing, I let you know how it goes Lee.