Practise 2-octave scales and arpeggios with a metronome.
Play them slowly at first and be very aware of every buzz, flam, flub, click, clack, etc.
Start with Ionian mode (major), around the circle of fifths, then Aeolian (minor), then Mixolydian (dominant), etc.
Move on and increase the speed only when you can play each scale, and arpeggio, consecutively clean.
However, as Jimmy states, the bass is a noisy instrument. But after honestly practising scales,
you’ll be flying around the fingerboard with much less noise before you know it.