4KD919671 Fuel Tank Sender Unit For Audi A6 C8

4KD919671 fuel tank sender unit for Audi A6 C8. The sender reports tank contents to the instrument cluster and supplies the signal used by the range display and the low fuel warning on this generation of the A6.

The part is a float on a wire arm running over a film resistor track, mounted in a plastic carrier that locks into the tank with a bayonet ring. A moulded O-ring seals the carrier to the tank, and the electrical side uses a sealed connector with a secondary lock. On the C8 the tank is a saddle design, so the sender sits in one chamber and works with a transfer jet that keeps both sides level; a sender that has been fitted with the arm out of position will read correctly only when the tank is full.

Fitment is the Audi A6 C8. Access is under the rear seat bench, through a round service opening on the right side. Fold the seat forward, remove the cover, disconnect the battery and unplug the sender before turning the ring. Because the arm is long, withdraw the sender vertically and do not let it scrape the tank wall, otherwise the float can be pushed off its stop.

Fault patterns include a gauge that reads empty when the tank is half full, a needle that jumps in steps, and a low fuel lamp that comes on too early or not at all. Before replacing, check the connector pins and the earth point behind the rear seat trim, because a corroded earth produces identical symptoms on this platform and costs nothing to fix.

Every sender is bench tested across the full arm sweep and the resistance curve is logged. The flange O-ring is included.