Still have a reoccurring SES with a fuel vent code. I thought that the connection to the fuel vent breather valve was bad, and after some work on the plug I could hear it clicking under the hood when I tested it via my foxwell. However, a week later I'm still getting the code and SES light occasionally so I ordered a new valve, which is an easy fix.
I had a fuel leak diagnosis pump and dust filter on hand too and since I wasn't hearing any noise from the left rear wheel well when I tested that system, I decided to pull the liner and replace them yesterday. I also did not want to get back on my old house window rehab project I've been working on for ever. The breather valve and the leak detection system are the only things that tie into the carbon canister, so I figure potentially a problem with one system, could be causing an issue with the other system and popping the code.
The liner comes out easily, and I've gotten smart enough over the last year or so to have a supply of blind rivets and the small exterior screws with washers on hand before jumping into exterior work that requires trim to be pulled. Happily all the plumbing looked factory new, as did the brake lines that run through there, and no rust to be seen at all. 20 years worth of dirt and grime to clean out though.
I tested the new pump for continuity and then screwed it to the bracket (three torx) and popped in the new filter. There is a rubber piece that fits over the pump nipple and makes the tight connection to the "filler breather" tube. Don't toss your old pump before removing this and moving it over to the new pump nipple. It doesn't seem to be sold separately so it must come with the breather tube, not the pump. Pic below shows this fitting, next to the nipple on the pump that it fits on. The tube won't fit without it:
The new pump "clicked" on and off with the foxwell test so I buttoned it up with new blind rivets and some replacement screws for those gone missing over the years. I'll toss my new breather valve in when it arrives next week and hopefully no more SES lights or codes. I'm not sure what else is left beyond bad wiring, broken tubing somewhere, or a bad charcoal canister (not sure how I would know this. All would be a lot more painful than replacing the above parts. The cost of a new canister is a bit painful to contemplate for a part that doesn't buy any more fun or upgrade when replaced.
Interestingly, I didn't smell a gas odor from the pump, dust filter, or any of the plumbing when I had it apart. I suspect the pump hasn't been working for years.
Update: the new breather valve arrived and I popped it in. The insulation on that wiring is super brittle. It tested fine with the foxwell (clicks on and off) and hopefully will be the fix.