If your vehicle is showing low fuel warning light stays on despite having a full tank, here are the most likely causes and the parts you'll need to fix each one.
The electrical resistor contacts on the fuel sending unit wear out over time, sending a false 'empty' signal to the dashboard.
Often occurring after a recent fuel pump replacement, the float arm can get bent or stuck against the side of the fuel tank, preventing it from rising with the fuel level.
Corrosion, moisture, or a loose connection at the fuel tank wiring harness interrupts the sensor signal, causing the vehicle's computer to default to a low fuel warning.
The instrument cluster may have a failed internal circuit board or processing error that incorrectly triggers the low fuel warning light despite receiving a correct signal.
The computer responsible for processing the fuel level signal and illuminating the warning light has a software glitch or hardware failure.