What could a buzzing noise during vehicle startup indicate?

A buzzing noise during vehicle startup can indicate that the starter solenoid is engaging, but the starter motor isn't turning. When the ignition is turned on, the solenoid is responsible for engaging the starter motor to crank the engine. If the solenoid clicks or buzzes but does not provide enough power to the starter motor, it can create a buzzing sound without the motor actually turning.

This scenario often occurs if there is insufficient voltage reaching the starter motor, possibly due to a weak battery or poor electrical connections. It might also occur if the starter motor itself is faulty or has internal issues that prevent it from turning, despite the solenoid engaging correctly. The buzzing noise is a clear indication of a problem within the starting system that requires further diagnosis.