A4988 not working


I have bought a A4988 motor driver. Im trying to use it with my arduino Nano IoT.

I recently bought a clone A4988 driver, but they were faulty. So I bought them from Polulu.

Unfortunately, I can’t get them to work at all now.

Please find the attached wiring diagram.

I’m not reading any voltage on the motor pins - the coils are not getting powered.

I have measured VMOT + GND and VDD + GND.
Both receive voltage.

Attached a picture of my soldered A4988. Seems like the Motor Driver is faulty?

Thank you for your help.


Please note, our company name is Pololu, not “Polulu”.

The soldering in your pictures does not look good and there are many joints that are not making good enough contact with the pads, so we should address that first. I recommend using the Adafruit Guide to Excellent Soldering as a reference for improving that.

If you rework your solder connections and it is still not working, can you post updated pictures? Can you also tell me what VREF is set to along with what power supply and stepper motor you are using (a datasheet or link to where you got it would be ideal)?


Hello Patrick,

thank you for your reply.

Sorry I misspelled Pololu :smiley: My bad.

Thank you, this was my first time soldering those pins. I will try improving it and give you an update then.


Dear Patrick,

my poor soldering was the problem.

Thank you very much!


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