No warning for gas cap left open?

oldguy00 · 07-25-2023, 06:59 AM

Woke up this morning to find my gas door and cap open. I did take it for a fill last night, and perhaps left it that way, although odd for me.

I started the car with it left open just to try, and car started, no warnings etc. Is that normal? Nothing supposed to pop up on screen to show it open? I presumably would have drove home from gas station with it like that...

nZtiZia · 07-25-2023, 07:47 AM

should have received a Check Control notification

streborx · 07-25-2023, 08:02 AM

Did you park outside overnight and is your tank still filled?

Qsilver7 · 07-25-2023, 08:08 AM

How far away are you from where you fueled up? The OBD II (check control) warning light will only illuminated after TWO detections of a fault.

A loose fuel filler cap will report a "leak" and illuminate the light...but the leak must be detected TWICE during a drive cycle in order to illuminate the warning light.

If you did drive off with the cap loose...I would have to guess that during your drive cycle, the sensor didn't get a chance to report the 2nd time before shutting the engine off.

If you have an OBD II tool (even a simple generic one)...you should be able to pull up any PENDING codes...this would be an indication that the loose cap was detected...but just once...not the 2nd event that would have illuminated the light.

See 2nd paragraph in 3rd bullet in the info below about the OBD II federal mandate & check engine light:

David3 · 07-25-2023, 08:13 AM

I believe (definitely could be wrong here) a BMW only checks for fuel tank/evap system integrity at cold starts. So, it would take two cold starts for the CEL to be illuminated. So, in a way, yes there is a warning that you left the fuel cap open/off...the CEL.

nZtiZia · 07-25-2023, 08:14 AM

Quote:

Originally Posted by Qsilver7

…
A loose fuel filler cap will report a "leak" and illuminate the light...but the leak must be detected TWICE during a drive cycle in order to illuminate the warning light.

…

I was speaking more to a notification that the fuel filler door was open which he should’ve received as soon as he started the vehicle. no driving or two-time detection required…

David3 · 07-25-2023, 09:01 AM

I know, I was just being "cheeky" as the Brits might say. Anyway, I cannot recall ever owning a BMW with a fuel door position sensor. Since an open fuel door is not a safety issue, I cannot imagine one being fitted.

nZtiZia · 07-25-2023, 09:21 AM

Quote:

Originally Posted by David3

I know, I was just being "cheeky" as the Brits might say. Anyway, I cannot recall ever owning a BMW with a fuel door position sensor. Since an open fuel door is not a safety issue, I cannot imagine one being fitted.

oh I didn’t take it like that at all! great info on the CEL detection. I learned something new

maybe I’m confusing the notification we get for an open charging door…

oldguy00 · 07-25-2023, 09:42 AM

Thanks for replies. I am only about a 5 min drive from gas station, then the car sat in driveway overnight. I did start the car without replacing the cap just to see, and no warning came on, but I did not try driving with it like that again.

07-25-2023, 06:59 AM	#1
oldguy00 Second Lieutenant 111 Rep 230 Posts Drives: 2022 X5 xdrive40i Join Date: Dec 2020 Location: Canada iTrader: (0)	No warning for gas cap left open? Woke up this morning to find my gas door and cap open. I did take it for a fill last night, and perhaps left it that way, although odd for me. I started the car with it left open just to try, and car started, no warnings etc. Is that normal? Nothing supposed to pop up on screen to show it open? I presumably would have drove home from gas station with it like that...
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07-25-2023, 07:47 AM	#2
nZtiZia Major General 4715 Rep 8,776 Posts Drives: eVeRyOnE mAD! Join Date: Dec 2020 Location: neither here nor there... iTrader: (0) Garage List 2021 BMW X5 xDrive 45e [9.88]	should have received a Check Control notification
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07-25-2023, 08:02 AM	#3
streborx Major 664 Rep 1,094 Posts Drives: 2022 BMW X7 M50i Join Date: Jul 2022 Location: Colorado iTrader: (0)	Did you park outside overnight and is your tank still filled?
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07-25-2023, 08:08 AM	#4
Qsilver7 Major General 4492 Rep 7,535 Posts Drives: F06 650ix GC / F15 X5 50i Join Date: Oct 2016 Location: Indiana, USA iTrader: (0)	How far away are you from where you fueled up? The OBD II (check control) warning light will only illuminated after TWO detections of a fault. A loose fuel filler cap will report a "leak" and illuminate the light...but the leak must be detected TWICE during a drive cycle in order to illuminate the warning light. If you did drive off with the cap loose...I would have to guess that during your drive cycle, the sensor didn't get a chance to report the 2nd time before shutting the engine off. If you have an OBD II tool (even a simple generic one)...you should be able to pull up any PENDING codes...this would be an indication that the loose cap was detected...but just once...not the 2nd event that would have illuminated the light. See 2nd paragraph in 3rd bullet in the info below about the OBD II federal mandate & check engine light: __________________ 2015 F06 650ix Gran Coupe`(Moonstone/Cohiba Brown)\| 2014 F15 X5 50i MSport (Space Gray/Mocha) Become a BMW CCA member! Click HERE to join and feel free to use my BMW CCA member #191509 as a referral.
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07-25-2023, 08:13 AM	#5
David3 Second Lieutenant 124 Rep 219 Posts Drives: E21 (x2), E46, F15, G05 LCI Join Date: Sep 2014 Location: Austin, TX iTrader: (0)	I believe (definitely could be wrong here) a BMW only checks for fuel tank/evap system integrity at cold starts. So, it would take two cold starts for the CEL to be illuminated. So, in a way, yes there is a warning that you left the fuel cap open/off...the CEL. Last edited by David3; 07-25-2023 at 08:20 AM..
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07-25-2023, 09:01 AM	#7
David3 Second Lieutenant 124 Rep 219 Posts Drives: E21 (x2), E46, F15, G05 LCI Join Date: Sep 2014 Location: Austin, TX iTrader: (0)	I know, I was just being "cheeky" as the Brits might say. Anyway, I cannot recall ever owning a BMW with a fuel door position sensor. Since an open fuel door is not a safety issue, I cannot imagine one being fitted.
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07-25-2023, 09:42 AM	#9
oldguy00 Second Lieutenant 111 Rep 230 Posts Drives: 2022 X5 xdrive40i Join Date: Dec 2020 Location: Canada iTrader: (0)	Thanks for replies. I am only about a 5 min drive from gas station, then the car sat in driveway overnight. I did start the car without replacing the cap just to see, and no warning came on, but I did not try driving with it like that again.
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