I have an 09 s2, and I have recently run into issues with my fuel gauge. It never displays a low fuel light, and will run out of fuel right below a displayed quarter tank. Upon testing resistance in the fuel floaters, both the left and right fuel floaters range from approx. 9 ohms at the top of their range of motion to EXACTLY 277 ohms at the bottom of their range of motion. I recognize that this is out of spec according to the service manual, but I am suspicious that the numbers in the service manual are inaccurate, as it seems unlikely that both of my fuel floaters would fail at exactly the same time, to exactly the same resistance. Upon unplugging any combination of fuel floaters (left only, right only, both) the fuel gauge displays empty and the fuel light comes on. Has anyone measured the resistance of a known working floater, and if so, would they be so kind as to share those values? I hesitate to spend $300+ on parts that may not fix anything, and having spent a lot of time reading the workshop manual, I know it is less than perfect. I would also greatly appreciate some insight on how the wiring works on this, does the information from the sensor go to the PCM or does it go directly from the sensor to the gauges? I have seen people saying the latter, but I am inclined to take this with a grain of salt, since I have access to the fuel level percentage as a raw value from my scan tool, and this would seem to suggest that the value is digitized then sent to the gauges. Any insight on these issues would be greatly appreciated, and if there is a thread on this issue (specifically a consistent failure in the resistance reading of the floaters) please point me to it.

 

Same thing here with the S1 2004. Seems my fuel level gauge can stuck to 1/4 and run out of fuel to the very last drop. Measured both float sensors with the exact same ohm-figures 9-300 ohm range.
In my case the wiring of the fuel pump side float sensor was damaged, and could have come into contact with a metal object in the fuel pump resulting in wrong reading. Tried to reroute the wire for not coming into contact, but still cannot confirm this solved the issue as I do not want to drive the tank to empty. Using odo-meter to track miles per gas filled for good measure.

 

Great post, excellent question, well supported!

If you're already in the service manual, I'm going to assume it doesn't say anything about expected values. Have you tried the electrical manual? It's a major PITA to access, because it's a freaking Flash application... I set up to peruse it once upon a time, but didn't poke too deep because I didn't actually need anything from it at the time. You are in a different situation though, and seem technically capable of achieving the same end.

That's about the only reference I can think of barring someone else having their car torn down enough, having the correct tools, reading this post, and having the time available to dig in... Sorta tall odds.

One way to look at it, and assuming the electrical Flash manual is more time than the $300 is worth, is that the fuel sender/etc. is 16 years old and probably due a replacement anyway. Parts supplies are dwindling, and the production numbers are very low (especially S2s) to where there won't be much in the way of reproduction parts down the road. I had mine repainted recently, and the paint shop messed up the window seals. They work just fine in terms of keeping fluids where they're supposed to be, but there's a bit of a wave to them down the window frame. I'm going to track down replacements while I can, and save the wavy ones for down the road if needed.