# Stepper motor vibrates or buzzes but does not turn

> Fix a stepper motor that vibrates without turning: coil pairs wired wrongly, step rate too fast, current too low or an unpowered driver.

Canonical: https://roboticsengineering.in/fix/stepper-motor-vibrates-but-does-not-turn/ | Published: 2026-11-03 | Updated: 2026-11-03

**A stepper that buzzes in place usually has crossed coil wires or is asked to step faster than it can follow.** Check the coil pairs first.

## What the message means

A bipolar stepper has two coils, each with two wires. If wires from different coils are paired on the driver outputs, the field does not rotate and the shaft only shakes.

## Fix it in this order

1. Find the coil pairs with a multimeter. Two wires of the same coil show low resistance; wires of different coils show none.
2. Connect one pair to the driver A outputs and the other pair to the B outputs.
3. Lower the step rate. A motor cannot start at a high speed; start slowly and accelerate.
4. Set the driver current limit to match the motor rating, then recheck.
5. Check the motor supply voltage and the enable pin.
6. Check the step and direction pins in the code.

## Why it happens

A stepper that buzzes but does not turn usually has a swapped coil pair, too high a step rate, too little current or too low a supply voltage. A coil wired wrongly makes the shaft shake in place.

Find the two coil pairs with a multimeter: the wires of one coil show a low resistance, wires of different coils show none. Connect each pair to one driver output pair, lower the speed, and set the driver current limit for the motor rating.

## If you see this, do this

| You see | Do this |
| --- | --- |
| Buzzes at any speed | Coil pairing or no current. |
| Works slowly and stalls when faster | Step rate too high or current too low. |

## Related

[stepper step frequency](https://roboticsengineering.in/stepper-motor-step-frequency-calculator/), [stepper torque curve](https://roboticsengineering.in/stepper-motor-torque-curve-explained/), [A4988 or DRV8825 not moving](https://roboticsengineering.in/fix/stepper-driver-a4988-drv8825-not-moving/).

Last reviewed: November 2026. These are the usual causes and the order that finds them fastest. Test on your own board; clones and cables differ.