No current to stepper motor with the A4988 driver

So I have spent the past couple of days working to get a stepper motor work using an Arduino Uno R3 and the A4988 Stepper Motor Driver. This is a link to the driver itself ( However, upon setting it up I have been unable to get any current to be delivered to the motor from the driver.

To set this up, I used a setup and code pretty much identical to the set up in this tutorial video ( The driver in the video is slightly different then the one I am using but I set it up very similar. I ignored the REF, 3V3, VDD, 5V and GND terminals in the upper righthand side of the picture in the overview section in the link above. I instead used VDD in the lower left, supplying 5V from the Arduino. For the stepper motor I am using a NEMA 17 bipolar 2A stepper motor.

I have tested every connection going into the board individually and simultaneously and all work accordingly but I get no signal at all from 1A, 1B, 2A, and 2B terminals. The only thing that I thought could be causing this would be the fact that for VMOT I am using a 5V power supply which is below the recommend range. I was wondering if anyone had any input on this? I didn’t know if this would undoubtedly be the cause or if it could be something else I’m overlooking. Any thoughs would be much appreciated, thank you.


The minimum operating voltage of the A4988 Stepper Motor Driver Carrier with Voltage Regulators is 8V; it will not work correctly with 5V.

By the way, please note that the maximum current per phase that this board can handle without additional cooling is 1A, which is significantly lower than the 2A rating of your stepper motor. To avoid damage, you should set the current limit to 1A (or slightly lower). You can find instructions for doing this in the “Current limiting” section of the #1183 product page.

If you still have problems after using an appropriate voltage and setting your current limit, you can post pictures of your setup that show all of your connections, and I’d be happy to continue troubleshooting.


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Hi Brandon,

I appreciate the response! With regard to the cooling aspect, if I were to get a heatsink for the driver would that be sufficient enough to run 2V?


While the A4988 driver IC has a maximum current rating of 2A per coil, the actual current you can get from it depends on how well you can keep the IC cool. On our #1183 carrier, the current you can expect it to deliver in ambient conditions is about 1A per coil. However, it is very unlikely you would be able to reach the 2A per coil maximum rating of the driver IC even with additional cooling (e.g. adding a heat sink and forced air flow). Please note that we generally view adding a heat sink as an advanced modification that should only be made by those who have experience with this kind of thing. If you decide to try it, I suspect forced air flow would have a more noticeable impact than just adding a heat sink.