Loose gas cap has triggered Service Engine light

It's frustrating that we don't seem to have a good set of pictures for the connections from the fuel filler neck purported drain holes ... to the reputed connection at the charcoal canister ... to the connection with the purge valve ... and then on to the intake manifold near the throttle body.

Here, today, the topic of the drain holes came up again:
- E39 (1997 - 2003) > Gas leak when filling tank

Which, led to the specific thread on that topic:
- When I spill gasoline and it flows into holes at 3 & 9 o'clock ... where does it go?

Which contains many disjoint diagrams, few pictures, and even less of a description of how the system is tied together and where.

To further embarrass myself, here is what I 'think' the system is connected to on my 2002 M54:

a) The two holes in the passenger-side rear fuel filler opening ...
b) Are reputed to drain to the charcoal canister hidden in the driver side rear wheel well ...
c) Which then goes along the underside of the driver side of the vehicle ...
d) Past the fuel filter & fuel pressure regulator in a panel outside the car directly under the driver seat ...
e) To the purge valve located under the front of the intake manifold ...
f) And finally, into the intake manifold at a vacuum source very near the throttle body (under the throttle body?)

Are these proposed endpoints accurate?

I have the 1998 528i - 4/98 mfg date. I used the tool to pull the code, and yes
the code was indicative of the fuel tank cap being off - gross vac leak or something.
I reset the code with the tool.

I was researching an answer for this thread today ...
- E39 (1997 - 2003) > 2001 530i question...

Originally Posted by stoneman1027

I got my 01 530i back in June and i still cant pass the emissions test ... it needs to complete the drive cycle. that was over 3000 miles ago.

... When I realized we should probably consolidate the powerful information in the following three threads:

1. E39 (1997 - 2003) > When are E39 OBDII diagnostic trouble codes (DTCs) & pending codes auto cleared?
2. E39 (1997 - 2003) > Loose gas cap has triggered Service Engine light
3. E39 (1997 - 2003) > Missing Gas cap and check engine light

new member, just joined after all the helpful comments i read on this forum and spending 8 days for my light to go away after the attendant left my gas cap loose.

engine light came on, just a few second after a brief flash of a "loose gas cap" indicator light (had to google it to find it, looks like the bumper of the car with a giant flashlight pointed at it). the loose gas cap light went away after this flash, the CEL never went away.
tried a few "drive cycles" - even using the FTP as a guide to reset the stupid thing - no luck.

BMW dealership wanted to charge half an hour of service (ie. $100) to read the code and clear the light but also told me that the light should generally go away after a while depending on personal driving style etc. Finally got frustrated (and too obsessive to drive around with a CEL on) so took it to independent shop who read the code and cleared it for $50. In canada we don't have AutoZone or other places who read for free.

Probably should get a a card reader but have decided to stick to my day job and let someone who know what they're doing deal with my car issues, seems like I've found a great independent mechanic in town who will do just that.

so there you have it, might have gone off by itself but at least i have peace of mind now.

Welcome to the cruel reality of BMW maintenance, which fortunately is usually outweighed by pleasure of BMW driving. Good luck with your new car. It looks like you got 3-series. Is that right? If so, you may want to post on the appropriate 3-series board, where you'll probably find more pertinent help than here on the E39 board.

Saw this thread andI thought I'd give some input.

I had the same recurring code that was caused by a poor seal. I inspected my purge solenoid and associated hoses... the fix was to lube the gas cap seals with silicone grease.

I bought a 2001 540i, sport package this week with 92000 miles. The cel is on.

When I tighten the gas cap, i go clockwise to one click. When I release the cap, it turns back counter clockwise and clicks again...normal? I had the cel diagnosed and cleared at a local autozone. I was told it was a potential gas cap issue, but didn't get the code. She did mention something about the vacuum. I was told that intake manifold gaskets were replaced before I bought it.

The only other thing I have done is lube the gasket with silicone.

When I compare the fuel tank neck to my 1999 528, they are different. I even tried the other gas cap, wouldn't fit. I seem to remember this being an issue when I first bought the 99, and may have had a whole new neck and cap replaced.

For the record, this thread came in handy for this one below:

Originally Posted by RyanBMW17

so here is my dilemma

I filled up my gas tank and forgot to put the gas ca back on. I drove 50 miles before the light came on and I realized what I did. I put the cap back on and since have gone 2500 or so miles and the light did not shut off.

So I went to AutotZone to try and gather more info, the guy said he could not test anything because there is a blown fuse. I'm not sure what fuse to check or what Ill need to do next to get the light to shut off.

I'm assuming the gas cap being left off in the first place is the problem, but anyone have any ideas?

thanks

2001 BMW 325i 134,000 mi

For the record, this P0455 thread today needs to read what we have here:

Originally Posted by Tdarrington

It is pulling a PO455 code. I noticed the light went on after I cleaned the motor and undercarriage so I wonder if I hose or a wire came loose.