98 v70 NA P0455 - my most loyal friend

Post by **98v70dad** » 16 Dec 2015, 05:53

First let me start by saying I detest P0455. This has been plaguing me for over a year now. I managed to knock it out for about 12 months but its back.

Anyhow, I've decided to take a schematic of the evap and PCV system and systematically mark off what has been replaced so I can focus on what's old.
I know there is a good schematic someone drew of the system(s) for one model of the 98 V70 or 850. I've looked for it for a long time and am wondering if anyone knows where it is or can give me a link? I spent some time Saturday going over the PCV system and the valves and hoses in the engine area and I've replace ALL of that stuff.

There is one elctro-mechanical valve just under the battery tray and on top of the charcoal canister that is on the line going back to the fuel tank (I think). I have never seen anyone talk about that one or what it is. Does anyone know? When I did the PCV mod and upgrade I pulled the charcoal canister and replaced all of the elbows attached to it with OEM parts from the dealer. This item is separate from all of that. Other than this valve ---whatever it is -- I have replaced EVERYTHING (including the shut off valve and the hose to it up front. The stuff in the back by the fuel tank is another story. I've not replaced anything back there. That's why I need the schematic so I can learn and understand what could need my attention back there.

I recently had a problem with gas pump shutting off frequently when filling the gas tank coupled with P0455 codes. I replaced the old DORMAN purge valve with an OEM one from the dealer and the problem completely went away for a few months. Now both items are back. I don't know what to make of it but these are the only symptoms I've got to go on to troubleshoot this.

2 years and I won have to get it emissions tested anymore.

Post by **cn90** » 16 Dec 2015, 05:58

I think you talked about all those issues in that EVAP thread.
You just need to spend more time and read through those threads.

My experience shows me that:
- Large leak is usually: the EVAP hose above gas tank.
Rarely it is gas cap seal.

- My P0440 code is from EVAP Valve. I used Bosch (made in China) but failed within 2.5 years.
I just switched to Pierburgh Valve, so far so good:
https://www.matthewsvolvosite.com/forums ... =1&t=54546

Post by **98v70dad** » 16 Dec 2015, 07:00

cn90 wrote:I think you talked about all those issues in that EVAP thread.
You just need to spend more time and read through those threads.

My experience shows me that:
- Large leak is usually: the EVAP hose above gas tank.
Rarely it is gas cap seal.

- My P0440 code is from EVAP Valve. I used Bosch (made in China) but failed within 2.5 years.
I just switched to Pierburgh Valve, so far so good:
https://www.matthewsvolvosite.com/forums ... =1&t=54546

Much of the background information I wrote here is from the previous thread but the question about the unknown thing on top of the charcoal canister is completely new. I have never seen it mentioned anywhere. It is probably mentioned somewhere but it may be located in a different place on an earlier or later car. Or possibly it was mentioned somewhere and I didn't understand what they were talking about at the time. That's why a referenc schematic would be helpful. I probably should have added the new question to the EVAP thread but its a different question and people typically don't respond to old threads, especially if you start adding new questions and the initial question was already answered. I apologize if this was the wrong thing to do.

I used to do this sort of thing for a living. I had a fleet of several hundred to take care of. Its very frustrating to know you can fix the problem once you have the correct knowledge but without that knowledge you're just throwing parts at it, using your best judgement and hoping. I am used to solving problem like this by a) pulling up the system schematic b)reading the manual on the system operation to see what failed part would cause the condition c) talking to the mechanics to see which parts they replace most often d) reviewing the service bulletins to see if there are any known related issues and fixes or upgraded parts. The problem with the EVAP system, particularly in the back, is its very difficult to access to get a look at it and anything you disturb may be leaking after you've moved it even if it wasn't leaking before you touched it. I have spent countless HOURS reading the threads. They are helpful but apparently these cars were changed many times during the 98 model year. If you look at the Illustrated parts list, the 98 model year has 4 or 5 different configurations back in the fuel tank area. Most everything I've looked at is similar but doesn't directly relate to my car.

Post by **cn90** » 16 Dec 2015, 07:52

1998 was a funny year b/c Volvo keeps changing the location of the EVAP canister, sometimes it is under the chassis near the fuel filter, sometimes it is under the battery tray.
You just have to look for it.

Re diagram, it is in that link I posted. I think @xtrattitude4u did a good job with the schematic.
One clarification, the word "VENT" in that diagram below refers to "one-way valve" that allows atmospheric air to "enter" (not venting to the outside world) the canister to replace volume loss (gasoline being pumped into the engine creating vacuum in the fuel storage system). I will repost the image here:

Post by **cn90** » 16 Dec 2015, 07:56

The EVAP Hose above fuel tank is in this thread:

https://www.matthewsvolvosite.com/forums ... =1&t=60269

Post by **98v70dad** » 16 Dec 2015, 09:20

Thanks. I appreciate the help. My EVAP canister is in the front below the battery tray. My car has a valve of some sort below the battery box and above the EVAP canister. It has a wire harness plugged into it and a vacuum line on either end. From the relative location it looks to be in the line that goes back to the fuel tank between the fuel tank and the EVAP canister, but I haven't verified this. I have had the canister out of the car and never noticed this valve before. On my back working on the canister it wasn't noticeable but I can see it looking down in the engine bay below the battery tray. Maybe it is from another system and is completely unrelated. I can say that its definitely not the purge valve and it is definitely not the filter. The only thing in the figure you posted that I have not had my hands/eyes on is the rollover valve. It is not shown in the same location on the schematic you posted but but maybe the thing I'm trying to identify is the rollover valve? This is why I asked the follow up question earlier, I'm trying to ID something that I haven't seen in any of the other threads.

Post by **cn90** » 16 Dec 2015, 09:31

98v70dad wrote:...It has a wire harness plugged into it and a vacuum line on either end. From the relative location it looks to be in the line that goes back to the fuel tank between the fuel tank and the EVAP canister, but I haven't verified this...

Did you click on the link I posted above (2nd post), it has the photos of the Purge Valve (Bosch vs Pierburg)?
I will repost the image here:

jcdillin · Post by **jcdillin** » 16 Dec 2015, 10:09

The motor that is attached to the underside of the battery tray is your cruise control pump, that goes to a single tube that goes back through the firewall.

The purge valve is mounted like the above image it's just round, quick test for it would be to pull of the hoses and blow through it, if you can blow through it then it's bad.

Post by **98v70dad** » 16 Dec 2015, 10:44

Yes, thanks. I know what the purge valve is. I've purchased and replaced it twice during the time I've owned the car. I'm looking for a large vacuum leak and I've already replaced everything that I know of in the EVAP system up front in the engine bay. I didn't think of the cruise control system because I don't use it. Thanks for helping me ID that. I doubt a P0455 code would result from leaks in the cruise control vacuum so I can eliminate that from my list to check.

Post by **98v70dad** » 16 Dec 2015, 10:56

cn90 wrote:
98v70dad wrote:...It has a wire harness plugged into it and a vacuum line on either end. From the relative location it looks to be in the line that goes back to the fuel tank between the fuel tank and the EVAP canister, but I haven't verified this...
Did you click on the link I posted above (2nd post), it has the photos of the Purge Valve (Bosch vs Pierburg)?
I will repost the image here:

Yes, I did. It looks like a great thread and I will read it tonight when I get home because there is a lot of good info there. I'm sure I'll learn something and with the added benefit of not getting dirty doing it. Thanks again for the help and the repost, but my question was about something that is "definitely not the purge valve" as I mentioned. Another person pointed out that the item I am trying to "ID" below the battery tray belongs to the cruise control system. That makes sense. I don't ever use cruise control so the thought didn't occur to me.