Sending unit (sensor)

A sending unit or sensor converts a physical condition into an electrical signal for the dashboard or engine control unit. Common examples on a motorcycle are the fuel level sender in the tank, the coolant temperature sensor, the oil pressure switch, the gear position sensor, wheel speed sensors for ABS and the throttle position sensor.

Older senders change their resistance, while modern sensors may send a voltage or digital signal. A faulty sender can show a wrong reading, a warning light or, if the ECU relies on it, poor running.

Before replacing a sensor, check connectors and wiring for corrosion or damage, especially on bikes used in winter or off-road. The service manual gives test values for most senders.