Happened about 3 weeks ago when I apparently over filled my tank. Going by similar issues when I googled the issue. Happened again yesterday and I only filled my tank to just over half full, which makes me think the sender unit id faulty and on the way out. Anyone suffered from the same issue, and is it a lengthy and expensive job to replace the fuel tank sender unit? Audi A6 2.7 tdi Quattro. 84k 2010.