P0455 - Should I fix it?

[prwood]

My '01 V70 has had a P0455 code on it ever since I bought it in 2015. I know there is plenty of documentation on this site about how to diagnose and fix the P0455 code. However, most of those questions are asked in the context of cars needing to pass an emissions test. With my car, at this point, it is no longer required to pass emissions tests due to its age (in MA if it's older than 15 years it's exempt from emissions, but not safety). So I don't have *that* reason to fix it. In the past we have taken some steps to try and address it (replacing gas cap, replacing EVAP valve mounted on top of radiator fan cowl), but it has eventually come back, so we haven't put any further effort into it at this point.

My question is, other than being able to pass an emissions test, is there any other reason to fix it? Do any of the problems that would cause the P0455 code affect safety, performance, or fuel economy in any significant way?

[abscate]

If you don't smell any gas around back of the car on a hot day, ignore it and drive on. Im pretty green, but this system is so sensitive a tiny leak will throw a code which you can chase for years. My 1999 sometimes doesnt go ready for 2000 miles - then throws P0455 about half the time.

[kranz]

I have this code as well on my '98 V70. I checked all the obvious and easy stuff to no avail. I am now old enough to apply for the senior exemption from the annual Georgia emissions check. But I have to limit my mileage on this car to 5K per year. This is not a problem as it is a 3rd car. Car seems to run fine, so I've felt no urgency to find the source of the code. I suppose I'll get around to it eventually.

[Georgeandkira]

There are long and short hoses, a filler neck, a purge valve, a charcoal canister, sensors, the gas cap and many points of coupling.

It's too bad they don't just prescribe replacing the whole lot. If it was reachable it wouldn't cost that much.

Try smoke detecting a pinhole leak.

[abscate]

I have this code as well on my '98 V70. I checked all the obvious and easy stuff to no avail. I am now old enough to apply for the senior exemption from the annual Georgia emissions check. But I have to limit my mileage on this car to 5K per year. This is not a problem as it is a 3rd car. Car seems to run fine, so I've felt no urgency to find the source of the code. I suppose I'll get around to it eventually.

Thats just peachy...

The problem with these cars evap cycle on the P80 + bastards is the sensitivity of the cycle to drive conditions.

If you do any of the following

Full throttle (more than 3/4)
AC on
Exceed 60 mph
Less than 1/4 or more than 3/4 tank gas

your drive cycle is cancelled and you wait another one to go ready.

Sometimes I drive a month without not doing all four of these...

[prwood]

wasIf you don't smell any gas around back of the car on a hot day, ignore it and drive on. Im pretty green, but this system is so sensitive a tiny leak will throw a code which you can chase for years. My 1999 sometimes doesnt go ready for 2000 miles - then throws P0455 about half the time.

So, today was a bit hotter than normal, and lo and behold, I did smell fuel when I walked behind my car. I also got a message on the dashboard "FUEL FILLER CAP LOOSE-OPEN," which it wasn't, but I know that's part of the EVAP system. So... what is the recommended sequence of troubleshooting steps? My father-in-law's typical advice is "start with the cheapest fix first," but I'm not sure what that would be in this case.

[Georgeandkira]

You did a fuel cap...how long ago? A small tempo cheat is to smear silicone grease on the gasket or wrap the thing in a plastic bag so it seals better.

Get a larger pop rivet gun and 10 body sized pop rivets and drill out the pop rivets which hold the rear fender liners in place.
Use a 3mm (like 1/8") bit.
Start on the fuel filler side. When you see the neck you can see if you have the "wrapped grounding strap" which can wear a hole in the plastic or aluminum neck.

But here's the cool thing. Get a 18" long hunk of old garden hose and heat one end in boiling water to soften it.
Go the the vent in the air filter mounted at the top of the filler neck. It points down.

Shove the hose on and blow into it. I was rewrded with a hiss. I could zero in on the location and found the UNFORGIVABLY CHEAP "J" hose. Everything under there is butch. The "J" hose is like a 3 year old's jelly sneaker-a $20 part from Volvo but you can use any quality 1/2" hose.

It's no big deal to do what I have described. Do you have tools?

[prwood]

You did a fuel cap...how long ago? A small tempo cheat is to smear silicone grease on the gasket or wrap the thing in a plastic bag so it seals better.

Get a larger pop rivet gun and 10 body sized pop rivets and drill out the pop rivets which hold the rear fender liners in place.
Use a 3mm (like 1/8") bit.
Start on the fuel filler side. When you see the neck you can see if you have the "wrapped grounding strap" which can wear a hole in the plastic or aluminum neck.

But here's the cool thing. Get a 18" long hunk of old garden hose and heat one end in boiling water to soften it.
Go the the vent in the air filter mounted at the top of the filler neck. It points down.

Shove the hose on and blow into it. I was rewrded with a hiss. I could zero in on the location and found the UNFORGIVABLY CHEAP "J" hose. Everything under there is butch. The "J" hose is like a 3 year old's jelly sneaker-a $20 part from Volvo but you can use any quality 1/2" hose.

It's no big deal to do what I have described. Do you have tools?

Re: Gas Cap: I think we got a new (genuine volvo) fuel cap when we bought the car in 2015, and after we first started getting this code, we tried an aftermarket (Duralast) cap, but it didn't seem to make a difference, so we went back to the Volvo cap. That being said, looking at the cap now, I can see that there are a number of hairline cracks in the gasket material:

gascapgasket1.jpg (318.37 KiB) Viewed 5446 times

gascapgasket2.jpg (158.95 KiB) Viewed 5446 times

Obviously those images are zoomed way in, but I suppose it doesn't take much for fuel vapor to escape. $10 at the local parts store to try an aftermarket cap again probably isn't too much of a gamble. AutoZone has both a "push vented" and "standard" version of the cap. Does it matter which one I get?

Re: Getting access to the filler neck. My father-in-law and I have a communal toolset, and although I know I haven't bought one there's a chance he might have a rivet gun. It doesn't sound too difficult.

[Surfmullet]

This issue has vexed me for years in my 2001 Volvo S60 2.4T but I kept diagnosing it out of stubbornness. The OBD2 scanner kept coming up with P0455 code even after I fixed the J-hose, got a new evap canister, tightened all exhaust system hose connections and of course got a new fuel cap. The warning light kept flashing "gas filler cap open or loose" every time I filled up the car with gas and then I would get a Check Engine Light after about 130 miles of driving. The latest smoke test revealed that the leak only occurred at the vent common to the fuel neck.

After lot of money and determination, I ended up with a very simple fix. I made the fuel vent outlet smaller using an end cap with a 3/16" dia hole. (See attached). It made sense after some thinking. Evap System Leak Detected (large leak) = No pressure in the system. Put more pressure in system by limiting the vent output.

Worked for me. Good Luck.

[br0dy519]

Did you do a leak detection pump self-test ?