fuel/temp gauge problem

[martyn brooks]

hi i have a 2004 a6 tiptronic 130 tdi c5model...my problems are as soon as i turn the ignition on the fuel gauge jumps straight up to the half way mark as i put fuel in it rises up accordingly and when it goes back down to half way mark the yellow low fuel warning light will light up???????????? turning ignition of the needle will go down to zero..seems sender in tank is ok .just gauge reading wrong.had car on a snap on vag ang gauges showed no fauls????????? also temp gauge jumps up quarter .so when up to normal temp it reads 110dgs instead of 90dgs can anybody help please

 

[martyn brooks]

hi has anybody got any answers for the above please..does anybody know where voltage regulator in the instrument cluster is ????????????????

 

[Shargo]

IIRC you can do some checks and settings with VCDS to see if it's the gauges or senders that's causing the problem.
If it's a quattro they have three sensors registering different levels of fuel, a quite common failure.

Edit/addded:
I think the gauges use a stepper motor or something of that type, not just voltage based.