Mesh Bed Leveling & PINDA Probe Issues

The PINDA (Prusa INDuction Autoleveling) probe is the inductive sensor built into the MK3S+'s extruder body. It detects the steel sheet without touching it, letting the printer measure the bed's height at multiple points and compensate for any warp — this is Mesh Bed Leveling, and it runs automatically before every print via the stock start G-code.

"Bed leveling failed" / inconsistent mesh

1. Check for debris on the sheet — even a small piece of dried filament under a probe point throws off that reading.
2. Confirm the sheet is seated flat — the magnetic sheet should lie flush against the heatbed with no lifted corners.
3. Let the bed and nozzle reach full temperature before probing — probing a cold bed and printing on a hot one introduces error, which is why the stock G-code waits for temperature first.

PINDA reads inconsistently between prints

The PINDA probe is temperature-sensitive — its exact trigger height shifts slightly as it warms up. The MK3S+ compensates for this automatically via the PINDA thermistor, but if you've disabled temperature compensation in the firmware or moved to a non-genuine probe, this is the first thing to check.

Tip: If mesh leveling looks fine but the first layer still isn't level side-to-side, re-check Live-Z rather than the mesh — the mesh corrects for warp across the bed, but the single-point Live-Z offset still sets the overall starting height.

Steel sheet warping

Repeated exposure to high bed temperatures (ABS/ASA) can permanently warp a spring-steel sheet over time. A slight warp gets compensated by mesh leveling automatically, but a heavily bowed sheet will fail leveling outright or produce a first layer that's good in the center and thin at the edges (or vice versa). Rotating between a smooth and a textured sheet, and avoiding letting the bed sit hot when not printing, extends sheet life.

Warning: Never force a heavily warped sheet flat by hand — spring steel work-hardens and can crack. Replace it instead.