@yogi said in E1 and E0 lock up stepper:
I run a single extruder, generally E0. I swapped in a new extruder stepper and now when I send any extrusion signal the stepper just locks up until I power off the machine.
Is the hot end at operating temperature? If you try to extrude with the hot end cold, then the motor will be energised but extrusion will be prevented, and you should get a "Tool N was not driven because its temperature is too low" message. You can use M302 to enable cold extrusion while you are running tests.