قطعی مدار فرستنده

A break in the fuel sender's circuit, so the module receives no signal at all. It reads as an out-of-range value rather than a wrong level, which is why the module reports the circuit rather than the tank.

The commonest break is inside the tank, at the sender's own terminals or in the short harness to the tank-top connector, where fuel and vapour attack the joints. The gauge behaviour distinguishes it: an open circuit usually pins the gauge to one end and stays there, while a failing float or track moves erratically. Test at the tank-top connector to split the circuit — that separates the sender from the harness in one measurement, and only one of those needs the tank dropping.