M209 - Set Auto Retract

planner Enable / disable auto-retraction. FWRETRACT

Enable or disable automatic retraction. This option is meant to help slicers that don’t support G10/G11. But it can be used to override retraction in any GCode.

When auto-retract is enabled, all reversed E-only moves are treated as retraction. (Recover moves are also automatically overridden.) When disabled, E retraction derives from G-code.


M209 S<flag>

Argument Description

Set Auto-Retract on/off



Most slicers today can generate G10/G11. But this option is useful for older G-code.

Though not currently very popular, both volumetric extrusion and firmware-based retraction (and/or M209) make G-code more immune to changes from one machine to another, and permit changing the hardware without needing to re-slice.

See related codes G10, G11, M207, and M208.