Gas Cap message - AGAIN!!!
 

Hello everyone,
I thought I'd put this out there as some of you have better access to information than I do.
Can someone with a FSM please scan or post if possible the diagnostic pages with the steps to determine the cause. I've been searching and reading but have found no systematic procedure to troubleshoot this issue - other than to replace the gas cap which I've done with a new GM unit. I am simply trying to find out the necessary steps and how to's for diagnosis as opposed to just replacing parts.
.....and no I am not overfilling the tank!
Thanks in advance guys and gals - I do appreciate it!

Is it P0452? Have you been using any fuel additive lately?

No additive, why do you ask?

Well, the time I had my P0452 buzzing, I just so happen to have Chevron fuel injector cleaner in the tank. The code was for the fuel tank pressure circuit. So then I changed out the FTP sensor. Well, after installing that and erasing the code, a few days later I had the code back.

Eventually the check engine light went out and never came back. The check engine light would only come on every so often anyway; not all the time. But the most interesting thing is, as soon as I burned up all the gas with the cleaner in it, the check engine light has never came back.

I'm certainly not being that fortunate. I'm glad your issue is solved.

You're going to have to get the car scanned for codes unfortunately. There are different sensors throughout the EVAP system that check for pressure and any one of those will give the "check gas cap" message. On our 00 SSEi it was a bad pressure sensor, like MACDRIVE was mentioning, but it's impossible to tell which it is unless you get it scanned.
Has your service engine soon light come on yet?

Which DTS code do you have anyway?

As far as trouble shooting the coded circuit; usually it involves checking the reference voltage to the sensor in the affected circuit, then checking the signal voltage going back to the PCM. The signal voltage has to be checked with the the sensor still plugged into its connector by back probing the connector. The key must be on to have the circuit powered up for these tests.

Have you checked out AllData's free 2003 Bonneville info? There's alot of stuff on there that pertains to 2000-2005 Bonneville / LeSabre.

Which code is being thrown would be helpful to help pin point the problem. Diagnostics procedures listed in the FSM requires a scan tool. Did you check the vent solenoid from this thread?

http://www.bonnevilleclub.com/forum/...hlight=gas+cap

The code received was P0440. Archon I had not forgotten about that post, in fact I found the vacuum lines by the passenger rear wheel and I got the 'click' while checking it was connected properly. I started to become unsure about which was the vent solenoid because you had mentioned previously 'The last one that I fixed was done by cleaning the vent solenoid by the rear wheel,' however later in the post there is a picture with a description saying it is on the driver side under the rear seat.
I guess I didn't want to seem like a complete idiot so I checked the lines but have no idea how to clean it. The only alternative I could come up with is that there are two vent solenoids then. If this indeed is what I need to replace do I start with the rear wheel or under the rear seat? ...Or, is it the other one in the engine compartment by the rear valve cover (couldn't find that one yet)?
By the way - where is that pressure sensor located please?

Seems out of all the possible codes to get this one is very general and elusive.
P0440 Evaporative Emission (EVAP) System
P0442 Evaporative Emission (EVAP) System Small Leak Detected
P0443 Evaporative Emission (EVAP) Purge Solenoid Control Circuit
P0446 Evaporative Emission (EVAP) Vent System Performance
P0449 Evaporative Emission (EVAP) Vent Solenoid Control Circuit

Thanks again everyone!

One is the evaporative vent solenoid, the other is the evaporative purge solenoid. ;) It would be easier if they had come up with less similar names. The part about being under the seat was in answer to your question about the other fuse block.

The picture that I posted in the last thread shows its location. It is tucked up where the body starts to rise by the rear wheel, and is under the car. To clean it, you have to remove it, and take it apart. Frankly, I don't recall if it was screwed together, held with plastic clips, or both. Take it apart, clean it up, and lube it with some silicone grease inside, and see if that helps.

Okay, I think I may have this now.
The vent solenoid is under the seat and that is the one I should clean.
Does this mean the purge solenoid is the one by the right rear wheel and is it cleanable too?
Thanks a ton for your patience!

You're getting closer. The only thing that you will find under the seat is the battery, some wires, and some fuses. The vent solenoid is underneath the car. If there was an axle that went from one side of the car in the back, that's about where it would be. Thats the one that you want to clean. The purge solenoid is under the hood. That has been known to cause some problems too but, let's worry about that later.

EVAP canister purge valve (I think) Located above the front valve cover.

https://i115.photobucket.com/albums/...K/DSCN0324.jpg

Purge Canister Solenoid
 

My 2001 SSEI had the same gas cap issue and it was the Purge Canister Solenoid.

Thanks for the picture, Mac...that is the purge solenoid, as you suspected. Jayman, you'll find that above the rear rocker cover on yours, right back where the injector sight shield attaches. You'll have to remove that to see it.

Yes Archon - I did mean underneath the car. Do I have to pay any attention to the one by the right rear wheel and what is it called then?
Thanks for the pic MACDRIVE that is awesome - I sure can tell where the saying comes from "a picture is worth a thousand words"
My ISP is acting up and I have a full day today but I will get at this and report back.
:beerchug:

The one by the wheel is the VENT solenoid...the one we've been talking about. The one that MacDrive pictured is the PURGE solenoid. Different parts that do different things. If you prefer to start with the purge solenoid, as it's easier to get to, we can. The only surefire way to tell if it's the problem is to replace it. However, you can try removing it, spray a little intake cleaner in it, and shake it out well, When you put it back on, put some silicone grease on the vacuum fittings to try for a better seal.

How does the filler neck look? I had a similar issue that replacing the gas cap didn't correct. The lip on the filler neck had a little bit of corrosion on it so the cap wasn't sealing properly. Cleaned it up and it's been fine for almost a year now.

I've been following this one...

I don't want to oversimplify and I am not that familiar with the differences on the 2000+, but I can tell you that after chasing all kinds of things on mine (yes, it was only a '97...), The real culprits of my P0440 code were small cracks in the evap ine connectors. the rubber connnectors were craked ever so slightly, but add them all up and I had poor running and a CEL.

It won't cost you anything to carefully inspect all the evap lines and any connectors or lines that need replacing can be done for very little out-of-pocket.

Worth considering, IMO. ;)

Thanks, I actually have done that too - I even went as far as polishing the lip first and putting a small amount of vaseline on the cap to help the seal.
It seems it may either be one of the solenoids or yes possibly bad tubing.

In most cases, the rubber connectors break down before the actual plastic (sic) tubing does. Most of the rubber connectors can easily be replaced with simple rubber vacuum hose. In my case, it took less than a foot each of 7/64" and 9/64", cut in lengths equal to the formed rubber connectors.

It doesn't work for tees and elbows, but there's not too many of those.

You'll find that virtually all of your conections and hoses for the evap system are plastic istead of rubber. The two going to the purge solenoid are. You can see one of them in the picture that Mac posted, the whiteish one on the right hand side. You can barely see the other black plastic one on the left. The other end of that one goes to a rubber connection on the throtte body, but that is too large for a standard vacuum hose. The white one runs down the firewall, to a metal tube, then back to plastic at the charcoal cannister.

The fittings to the charcoal cannister under the car are also mostly plastic. My memory is faiiling me here on whether part of the tubing going to the vent solenoid is rubber, or not. If it is, we're right back to where we started this, anyway. ;)

Yeah, thanks Dick! As I mentioned above, I wasn't sure how different the 2000+ are, but am just trying to help him eliminate the low cost possibilities before he has to spend money. ;)

Having solved my P0440 code with vacuum repairs after trying unsuccessfully by replacing the gas cap (like him) I thought I'd suggest that as a course of action.

Your help is always welcome, Mike. ;)

Lol! That's all well and good, but where's Jayman?

I wonder how he's doing with this. :?

Hello - I'm still hanging around. Being self employed my hours are irregular as is my ability to get to the car. That said I plan on digging into it this weekend and I shall report back here with findings, problems and more likely resolutions.
By the way I appreciate all the help and advice, and I find it most welcome too.
Cheers

Thanks for keeping us updated. Whatever you find and post back will be quite helpful for others tracking down the same problem.

That's right, and the rubber hose you see up front at the bottom of the picture is supposed to be plastic, but I busted it while taking the thermostat bolts out. So I had to replace it with a section of rubber vacuum hose and a vacuum splice connector on each end. :oops: :oops: :oops:

Hello everyone,
Here's an update on an old thread. I did manage to get under the car by the rear seat and clean out that 'solenoid' however nothing changed. Gas Cap mess was still on along with SES light. BUT..... after warming up here in the spring along with the rains (high humidity) the gas cap message stopped by itself (I think) and the SES lgiht went off. Has been that way for about 2 weeks now too.
Is this strange to you guys at all? Don't get me wrong I love it, just strange.
Jayman

Your winter-wet electrical connection dried out. Disconnect and clean it, then put dielectric grease on it before you plug it back in.

Actually our area is renowned for very dry winters - it seemed the humidity and rains corrected it. The car came from Vancouver Canada before, whose climate is very similar to yours.
Who knows!

Did you also lube the vent valve, while you had it out, with either silicone of white lithium grease? That would help it seal better, if that's where the problem is.