I just thought I'd post this because I searched high and low and could not find any information as to which fuel level sender is which..

This is for models equipped with quattro

The sender on the drivers side (sender 2 according to Haynes) is for the digital readout (miles of fuel left)..

The sender on the passenger side (sender 1 according to Haynes) is for the "physical" gauge

 

So I too have an Audi TT quatro and I'm having an issue with the fuel gauge as well. I recently just changed the fuel filter and fuel pump assembly but now my fuel gauge is out of weck. It constiantly says it's empty or half full even when I fell the tank. I tried to see if the float was maybe stuck but it has plenty of room. I also tried to mess with the fuses 15 and 28 but that didn't seem to work either. Does anyone else have any other ideas?

 

So my fuel gauge was acting up erratically for a while, so I changed fuel pump with sending unit/new. Also checked fuses they're good.
I got a special code reader for audi,That can diagnose a specific circuit. So I diagnosed my fuel gauge and this is what I got.
*00771 fuel level sensor (G) , short circuit to Earth.
what do you think? Any ideas where to start, and how to do it? Did you guys ever fixed your problem?
I hope this new info helps.

 

I was looking for a starting point and think that this DIY might be it. It looks like I need to replace the low pressure fuel pump. What side is it in? Is it difficult to replace?

please advice n thanks.