Grbl Error 4

I own a Mill Right Carve King and recently disassembled it and moved. After re-building the CNC machine, and testing it in Universal GCode Sender, I received an error:4” : _(“Negative value received for an expected positive value.”

I have searched the internet for a possible fix but can only find a list of errors but no remedies.

Can anyone help??

An error code is usually the effect of an alarm code, was an alarm code also present?

Does this always happen?
Have you tried multiple files? If not, please share the problem gcode.


You can also check the gcode file for negative values in relation to the F, N, P, T, or S words. Negative values for these are not allowed and throw Error: STATUS_NEGATIVE_VALUE in the firmware which is Error: 4.


Brandon Parker

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So after several hours of troubleshooting today, I found the cause of Error: 4. The feed rate in Universal GCode Sender was set to -33.

That fixed the error code but my X and Y steppers still don’t move although UGS says they are.

Do they kind of stutter? If that is the case, there are phase wires that are crossed.


Brandon Parker

The motors don’t respond at all. Today I’ll test the 2 stepper drivers (x andY).

What is the feed rate that ugs is set to now?

Sorry for the delay. I found that 2 of my stepper drivers were fried. I replaced and they all work now. Thanks for all the help.

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