3 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHFuel Evap System - Parasitic Battery Drain?
Reported or suspected cause
now
Reported cause
No successful repair reported for this finding.
1
Identified cause
0
Suspected cause
0
Reported fixes
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that report identifying a cause
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Reported cause · Original poster
Installed the new reed switch on the fuel filler neck yesterday and my issue is now resolved.
Leading evidence: 'now' (1 discussions report identifying this cause; no attributable repair resolution). Across 1 matching discussions, the most frequently mentioned possible cause is 'now' (1 discussions; 1 report identifying it and 0 suggest it). The most frequently discussed action is 'Fill car' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed · Original poster
Installed the new reed switch on the fuel filler neck yesterday and my issue is now resolved.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed · Original poster
After that was replaced, things seemed ok at first..
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion · Original poster
but then when attempting to fill the car with gas, it wouldn't accept any.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion · Original poster
Upon powering it back up and getting things running again, I started doing some testing to see where the parasitic draw is coming from � and a significant draw (over 1amp) was coming from fuse E6, the fuse that opens the valves needed to fill the tank.
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion · Original poster
Upon powering it back up and getting things running again, I started doing some testing to see where the parasitic draw is coming from � and a significant draw (over 1amp) was coming from fuse E6, the fuse that opens the valves needed to fill the tank.
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
3 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.
0 acknowledgements have no verified action link; they do not establish a repair result.
Generation: 20261027T044418Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
On my 2005 996 C4S, I was occasionally getting a P0442 small evap leak code. I first went down the path of replacing the gas cap, then the solenoid in the engine bay, and still got the code. Then the fresh air vent valve attached to the filler neck. After that was replaced, things seemed ok at first.. but then when attempting to fill the car with gas, it wouldn't accept any.
After some digging I discovered that I had dislodged the reed/magnetic switch held in next to the fresh air vent valve that opens up the valving to allow gas into the tank. I repositioned that switch, took the car to the gas station, and voila � all good.
The next day I drove the car about 60 miles, and upon returning home I got the P0442 code once again. Frustrated but not nearly as frustrated as I was 4 days later when I went to drive the vehicle and found the battery to be completely dead ... 0 volts. This had never happened before, even with multiple weeks of sitting, so it was quite a surprise.
Upon powering it back up and getting things running again, I started doing some testing to see where the parasitic draw is coming from � and a significant draw (over 1amp) was coming from fuse E6, the fuse that opens the valves needed to fill the tank. More interestingly, upon inserting the fuse and/or connecting the battery, I can audibly hear the valve click open immediately, despite the fact that I'm not moving the magnet in the filler neck that
should
activate the valve.
So my theory now is that the valve seems to be stuck in "stay open" mode, perhaps due to a faulty reed switch, and as such is drawing continuous voltage when the car is stopped. It would also explain an evap leak, as the valves should typically be closed during driving.
I've ordered a new reed switch but in the mean time, has anybody else seen this? Am I on the right track, or wildly off base?
Just to close the loop on this one. Installed the new reed switch on the fuel filler neck yesterday and my issue is now resolved. The valves click open as expected when the filler flap opens, they close as expected when it closes, and most importantly there's no parasitic draw at all anymore when the car is off and not in "refueling" mode.
Time will tell if my P0442 codes are a thing of the past but my fingers are crossed!
For those wondering, the part number of the reed switch is:
99661322401
