The Fuel Level Sensor (FLS) is a device located on the top of the fuel tank or fuel pump. The FSL turns the mechanical fuel level into an electrical signal that is sent to the Powertrain Control Module.
The signal received by the PCM determines how much fuel is available in the tank, and it also monitors the fuel consumption to determine fuel efficiency.
The P0461 OBD2 fault code is set because the input signal sent by the Fuel Level Sensor does not match the operating voltages established by the manufacturer.