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Low Fuel Warning Will Not Reset

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tngarren

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Feb 20, 2025
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'21 R18 Classic, 1250RT, Monster 1200, Low Rider 117, Bobber 1200, Z900RS, V-Strom 1050XT
2021 R18 Classic

Scenario - I needed to lift the rear of the tank to remove a couple USB power cables the previous owner had run under the tank. I waited for the low fuel warning to come on so the tank would be lighter. I rmoved the tank rear bolt and lifted the tank so that a small block of wood would elevate the tank a couple inches. I removed the USB cables and reattached the rear bolt. Filled the tank with fuel and warning light remained on for 20+ miles.

I pulled the main fuse and no change. I removed the tank rear bolt again and shook the tank up/down/side to side as much as possible to dislodge a stuck float. No change. GS-911 shows fuel empty indicator is on.

Thoughts appreciated.
 
Tbh, I would just continue to ride it, as the fuel level drops and sloshes about inside hopefully that will it ‘jiggle’ it free. I’d also go out of your way to give it some in Rock mode to get the vibrations running through the bike. Just make sure you set your trip to know how close you are to empty while you resolve this issue.
 
Any chance you damaged something when you lifted the tank? There is a plastic captive connector; which technically speaking, normally gets disconnected prior to lifting the tank, so as not to stress the plastic fitting on the fuel tank.

Folks have cracked the fuel line fitting under the tank and swapped out the plastic fitting, with a stainless steel adapter..

I'm not sure what sensor is used to determine the fuel level; definitely, keep us posted as to what you find...


Screenshot_20250913-163648.png
 
Here is the parts fiche. Part #1 is the fuel pump and part #8 is a warning switch. Is the part I circled on #1 the float?


w1.jpg
 
This is a copy paste from AI Google search……

The BMW R18 does not have a traditional fuel gauge but relies on a low fuel indicator that activates when the fuel level is critically low, typically around 1.1 gallons remaining
. This warning appears on the multi-function display as a yellow triangle with a flashing gas tank symbol, and a mileage counter will begin showing the distance traveled on reserve fuel. The low fuel sensor, which is part of the fuel pump assembly, detects when the fuel level drops to this point to trigger the warning.

Sorry can’t help further, obviously not a float. I’d persevere a bit longer with it, maybe double check any electrical connectors you’ve unknowingly disturbed underneath the tank (while pulling out the unwanted ones). Do you have a dealer nearby? Could pop by and ask a tech? Hope you get it sorted.
 
NOTE: The imagines below are from the R18 B / TC. Hopefully some of this helps; I'm pretty hopeful that you somehow dislodged a connector, while cable mining the previous owner's DC wiring:


1759228032957.png

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1759227795534.png

No. 1 on the image is the fuel pressure sensor:

1759226219517.png

No. 5 - Fuel-Pump Unit | Fuel-Level Sensor Connector: Maybe try reseating the connector; check for any corrosion or bent PINS within the connector assembly.

1759226325886.png
 
The good news - the low fuel warning indictor finally went off. The bad news - I have no idea why. It did go away between starts. Given that startup shakes the tank pretty hard, it could certainly dislodge a stuck float. But as some have stated, the bike does not use a float mechanism. Seems a mystery for now.
 
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