What Does This Error Mean?

Extruder motor skipping in Marlin is almost always caused by a partial nozzle clog creating back-pressure the stepper cannot overcome, or the stepper driver current set too low. Clear the nozzle and increase E driver current via M906 if hardware allows.

Affected Models

Any Marlin-based FDM 3D printer with a direct drive or Bowden extruder

Common Causes

Partial nozzle clog creating too much back-pressure for the extruder stepper to overcome
Extruder stepper driver current (VREF or digital current) set too low
E-steps per mm value incorrect — too high a value causes the motor to skip under load
Printing too fast for the hotend to melt filament at the required rate (heat creep)
Extruder tension spring too loose — filament slipping on the drive gear without a motor skip

How to Fix It

Clear the nozzle clog.

Heat the hotend to 20°C above the normal print temperature. Push filament through manually while the heater is hot to force through any partial clog. For stubborn clogs, perform a cold pull: heat to 90°C, push filament in until it catches, then pull firmly.
Increase extruder stepper driver current.

If the printer uses TMC drivers, send M906 E800 (increase the 800 value in small steps) and M500 to save. For analog VREF drivers, slightly increase the potentiometer on the E driver board. Too low a current causes the motor to lose torque and skip under resistance.
Check and calibrate E-steps per mm.

Send M503 and note the current E-steps value. Mark 100 mm of filament above the extruder, send G1 E100 F200, and measure how much filament was actually extruded. If significantly over or under 100 mm, recalculate E-steps and set with M92 E[value] and save with M500.
Reduce print speed and increase hotend temperature.

Printing too fast for the hotend melt rate causes the nozzle to build back-pressure that overwhelms the extruder. Reduce the print speed by 20% in the slicer and increase the hotend temperature by 5°C. If skipping stops, you were exceeding the thermal capacity of the hotend.
Check extruder arm tension.

On direct drive and Bowden extruders with a lever-style grip, a weak tension spring allows filament to slip on the drive gear. Tighten the tension adjustment screw until the filament has firm contact with the drive gear teeth. Too much tension crushes soft filament (TPU, silk PLA) — find the balance point where grip is firm but not deforming the filament.

When to Call a Professional

If the extruder motor skips immediately when cold and the nozzle is confirmed clear, the stepper motor itself or the driver chip may have a fault. These are replaceable components.