Anycubic Kobra 3 V2: 32 Known Issues and How to Fix Them

The Anycubic Kobra 3 V2 is a 2025 open-frame FDM printer with a 255×255×260 mm build volume, a 300 °C hotend, a 110 °C bed and four-color printing through the ACE Pro unit. Almost every owner complaint traces back not to the printer itself but to the filament path: broken fragments, false error codes, purging and the cutter. Below are 32 problems specific to this model, with symptoms, root causes and step-by-step fixes.

First, what Anycubic fixed on its own. According to the official upgrade write-up, the spacing of the Y-axis rails widened from 40 to 60 mm, the X axis got SG15 bearings, the nozzle was borrowed from the Kobra S1 for a better seal, a 720p camera was added and LeviQ 3.0 gained zoned leveling. Firmware later pushed the build area from 250×250×260 to 255×255×260 mm, from 16.25 to 16.9 liters. All of that cures the first Kobra 3's illnesses, but the filament path and the ACE Pro stayed the same — and they generate most of the errors.

ACE Pro: feeding, cutting and purging

1. Errors 11518 and 11519 while the filament is clearly feeding

The print pauses with a clog (11518) or tangle (11519) message while you watch the filament travel from the unit into the toolhead. Hitting Resume sometimes just clears the pause and printing continues — until it happens again half an hour later. After four months of testing, the Creative Bloq reviewer put it bluntly: the ACE Pro was the source of 99% of errors and problems.

The official wiki lists four different causes behind 11519: a tangled spool, filament pinched in the extruder gear, filament stuck in the buffer mechanism and filament stuck inside the unit itself. Code 11518 is even more interesting — the documented cause is abnormal feeding in the buffer mechanism, meaning the nozzle can be perfectly clean.

1. Retract all four filaments via Materials — Retract so the tips sit visibly inside the tubes above the toolhead.
2. Undo the two screws on the four-into-one hub above the toolhead and inspect the merge port — that is where fragments hide most often.
3. Check the buffer at the back of the unit. If one of the four followers sticks out further than the rest, take the buffer apart: blue clip, tube, two screws for an S2.5 key, then two for S2.0.
4. Re-route the tubes without tight bends and move the unit away from the wall. Too small a bend radius at the toolhead inlet is a classic source of false feed errors.
5. Measure the filament with calipers in several spots. The wiki warns explicitly that undersized filament cannot be gripped by the gear, and the printer reports an error for that too.

2. Filament fragments in the path: 11511, 11512 and "unknown consumable"

The nastiest pattern: after a color change the toolhead stops extruding and the screen shows 11511 (feed failure), 11512 (retraction failure) or "unknown consumable". You strip the toolhead, pull out a stub of filament, restart — and it repeats at the next color change. Owners describe it the same way: they can disassemble that toolhead with their eyes closed by now.

1. Pull the toolhead shell — it is held by clips, not screws — and inspect the clear window of the runout sensor. Small fragments lodge exactly there, confirmed both by owners and by the wiki.
2. Push the leftovers into the extruder with a length of filament while pulling the lever to the right.
3. Release the hotend with its latch and pull the remains out at 55–60 °C. Never go above 60 °C: hotter plastic smears along the channel instead of coming out.
4. Inspect the cutter blade. A dull blade crushes filament instead of slicing it, and every crushed tip becomes the next fragment.
5. Loosen the extruder tension screw. An over-tightened gear shreds filament: owners who have pushed 7 kg through the toolhead without a single clog run noticeably less tension than the factory setting.

3. The metal runout sensor flap wears through

This one gets diagnosed last. Cutting and retraction failures during multicolor prints come and go with no obvious trigger, and the culprit is a tiny teardrop-shaped metal flap — the filament-presence sensor inside the extruder. Its contact face wears away. One Reddit owner burned through two flaps and found that Anycubic does not sell the part separately: only the complete extruder, around $20. The community is modeling replacements, but swapping the whole assembly is the reliable route.

4. A worn merge hub causes false "filament broken" after 20 minutes

Printing runs for 15–30 minutes, then throws "filament broken" even though feeding works and the filament is right there. An owner of three Kobra 3 machines compared the toolheads and spotted a worn bore in the merge hub: the filament starts wobbling in the enlarged hole and loses contact with the sensor. The fix is a new hub, either original or printed — Printables has a four-into-one replacement for the Kobra 3 and S1.

5. Filament is not cut before a color change

The toolhead is supposed to move right, cut the filament and only then tell the unit to retract. Sometimes the order breaks: the head stays put, the ACE Pro starts pulling uncut filament back and you hear skipping. That damages both the unit and the hotend.

1. Hit Reset and check that the toolhead reaches its far-right position and is caught by the magnet.
2. Inspect the cutter blade: crushed edges mean the assembly needs replacing.
3. Update to firmware 1.1.2.8. The official changelog states it directly: improved multi-color stability, fixed idling and step loss in abnormal scenarios.

6. The purge wiper flings molten plastic onto the bed

After a color change you find smears of molten plastic on the plate and on the model, and sometimes a blob welds itself to the part and ruins the print. Anycubic has a dedicated troubleshooting page listing three causes. Notebookcheck went further and called it a design flaw: the wiper blade sits too far from the nozzle, and multicolor printing only became reliable after the tester glued on a rubber strip.

1. Pull the blade by hand: it must spring back on its own. If it does not, grease the shaft lightly.
2. Hit Reset and watch whether the mechanism is caught by the magnet. A loose magnet is tightened with an S2.0 hex key; a weak one means a new assembly.
3. If the nozzle scrapes the blade on its way past, lower the wiper slightly so they no longer touch.
4. Glue a thin rubber strip onto the blade so it hugs the nozzle more tightly.

7. Purge waste outweighs the part itself

On a multicolor model the mass of purge blobs easily beats the mass of the object — recorded both by Notebookcheck and by Tom's Hardware, where six figurines printed in 8 h 40 min at an average 130 mm/s produced around 100 g of waste. Three reasons: stock flush volumes are generous, the printer re-purges after every pause, and on runout or auto-refill the filament cannot be retracted, so the whole run from the unit to the toolhead is pushed out as waste.

• Edit the flushing matrix per color pair, not just the global multiplier: the slicer recalculates it on every color change, but that auto-calculation can be disabled in preferences.
• Add a purge object so the machine flushes into something useful instead of into thin air.
• Order colors from light to dark — a light color after black needs far more flushing.
• Kill the false pauses: on one run of non-existent errors the Creative Bloq reviewer lost almost 100 g of filament to repeated purges alone.
• Print a chute deflector and a bin: the most popular printed part for this problem has over 9,000 downloads.

8. Color bleed and dark streaks across light areas

White areas come out gray-tinged, and on light boxes and lithophanes dark lines appear exactly along the path to the wipe tower. Two different defects with one root: not enough flushing after a dark color, and a travel move to the tower without Z-hop, so the nozzle drags across the fresh layer. Raise the flush volume after black, enable Z-hop and rebuild the color order so light prints before dark.

9. What you must not load into the ACE Pro

Half of all "unit failures" are attempts to push unsuitable filament through it. The limits are written down in the official ACE Pro notes, and they are stricter than the box suggests.

• The unit can dry TPU 95A and HIPS but cannot feed them for printing — the wiki points you to an external spool holder. TPU 85A and softer gets flattened by the drive wheel and jams the channel.
• PLA-CF, glass-filled filaments and non-official PLA Silk are officially banned: they wear the channel, snap and jam.
• Matte PLA is not banned but is a frequent complaint: the smooth roller grips a rough surface poorly and the slot throws 11519. Try another slot, and if it repeats, feed it directly.
• Spool specs: 195–200 mm outer diameter, 60–68 mm width, 3–6 mm flange thickness. Cardboard spools only via a printed adapter ring.
• Before printing TPU, loosen the extruder tension screw by half a turn — a direct recommendation from the Anycubic TPU guide.

10. The ACE Pro does not wind filament back onto the spool

During unload the filament backs out of the toolhead by roughly ten centimeters and stops, with the unit's motors idle. This is not a fault: full return to the spool simply is not part of the ACE Pro design, and you finish the job by hand, turning the spool. Owners expecting AMS behavior spend whole evenings hunting a defect that does not exist.

11. Error 10409: "A problem occurred, please restart the device"

The print dies after a few hours, most often right after a color change. Per the code reference this is a communication failure on one of three links: ACE Pro to host, mainboard to driver board, mainboard to toolhead board. An owner running ten Kobra 3 machines got rid of it after repairing the head cable and grounding the external metal shell. A separate scenario: 10409 fires exactly when the app is opened — a video stream conflict.

1. Reseat the orange head cable, check that it has not chafed against the frame and tighten the connectors on the mainboard.
2. Ground the metal shell and shield the cable where you can.
3. Test whether the error repeats without the camera and with the app closed.
4. If 10409 appeared right after an update, roll the firmware back.

12. ACE Pro dropouts on signal cable extensions

Move the unit onto a shelf with an extension cable and 11503, 11513 and 11524 start rolling in. On the stock cable the same setup is clean. One owner tried extensions from two vendors, with and without a ferrite core; only one thing worked — wrapping the whole cable and all three joints in aluminum foil bonded to the printer chassis. After that: ten days and dozens of print hours without a single dropout.

13. Error 10536: the unit reports a bad ID

A brand new machine is assembled, all four filaments load and extrude individually, but starting a print throws 10536 and demands a unit restart. The documented cause is an abnormal unit ID due to unstable USB communication. Order of work: power off the ACE Pro, reseat the signal cable at both ends, restart the printer. If that fails, open the unit and reseat the signal board cable (two S2.0 screws). In one documented case support eventually replaced the whole combo — but it took six weeks.

Firmware, slicer and network

14. A firmware update breaks a working machine

The most common complaint after the ACE Pro itself, and the story is always the same: the printer ran fine, a notification arrived, the owner updated — and lost bed adhesion, or picked up clogs, 10409 or a full stop at random layers. The vendor indirectly confirms the area: the 1.1.2.8 changelog says it fixed idling and step loss during multi-color printing and a wrong purge position on resume.

1. Do not update in the middle of a production run. If the machine prints reliably, postpone the update to a free evening.
2. Right after updating, do a system restore and run the full calibration set: vibration compensation, PID and auto-leveling.
3. Verify the first layer on a test model before committing to a long print.
4. Keep a USB stick ready for rollback: the firmware file is renamed to update.swu and placed in a folder called aGVscF9zb3Nf on a FAT32 stick with an MBR partition table.

15. Black screen after an update

The worst outcome: after an update the printer hangs on the splash screen or shows no sign of life at all — not a single LED on the board, even with an intact fuse and a known-good power supply swapped in. USB recovery through the aGVscF9zb3Nf folder does not always work. If no LEDs light up, support is the only route left: in the documented case they shipped a head cable, a strain gauge and a mainboard.

16. Rinkhals will not install: wrong file, wrong firmware

The Rinkhals custom firmware is the only way to see a bed height map and get a web interface, but it will not install from just any configuration. The usual symptom: the installer shows "Rinkhals disabled", the FIX button does nothing and SSH never comes up.

1. Check your stock firmware version: for the Kobra 3 V2 the supported list names 1.1.0.4 and 1.1.2.8.
2. Take installer-k2p-k3.swu or update-k2p-k3.swu. The k3m file is for the Kobra 3 Max and simply will not do anything on a V2.
3. Rename the file to update.swu and put it in a folder named aGVscF9zb3Nf on a FAT32 stick with an MBR partition table — GPT is not supported.
4. Do not hand-edit the stock printer.cfg: the project authors explicitly decline to support machines that do.

17. Wi-Fi connects but the account does not

The printer sees the network and even joins it, but never signs into the account, and sending a file pushes it straight offline. Sometimes the screen simply hangs on the connection animation. The radio works on 2.4 GHz only.

1. Create a dedicated 2.4 GHz network on the router and switch 5 GHz off while setting up: with merged bands the printer often picks a network it cannot use.
2. Test through a phone hotspot — that is the standard support suggestion.
3. An owner trick that works: switch the region setting from global to China and straight back, after which the account login goes through.
4. Do not depend on the cloud: LAN printing and USB printing work regardless of the account state.

18. Camera: no bracket in the box, two frames per second after an update

The 720p camera ships in the box; its mount does not. The bracket model sits in the printer's memory and you print it yourself — the vendor confirms this in its own FAQ. The second half of the problem arrives with updates: owners report the stream dropping to two frames per second with flickering brightness, and third-party cameras splitting the image into three tiles. A jerky time-lapse, though, is not a defect: the bed moves and the frames smear.

The camera cable runs to the front USB port and, together with four tubes, tugs on the head cable. Separate them with a printed holder — Printables has a clip made specifically for the Kobra 3 V2 with ACE Pro.

19. AI detection pauses prints for no reason

Code 11801 — spaghetti detected — on a perfectly healthy print. The Creative Bloq reviewer disabled detection after three prints: too many false pauses, and every pause drags an extra purge behind it. Early firmware had no sensitivity control at all; it was added later. Anycubic's own advice for this code is aimed at the first layer: 0.2 mm first layer height with a 0.4 mm nozzle, 45–50 mm/s first layer speed, one slow layer, a skirt enabled and the plate wiped with alcohol.

20. Slicer bugs: error 10115 and the by_highest_temp hang

Two separate but equally frustrating stories. Anycubic Slicer Next 1.3.9.4 injects Prusa-specific QuietR and SportR parameters into M73 progress lines even when the flavor is set to Klipper — the printer cannot parse the file and throws 10115. In OrcaSlicer the symptom differs: the print settings show by_highest_temp instead of temperatures and the job hangs on "Preparation: analyzing…", while the same file sliced in the stock slicer prints fine and shows a normal 60/230.

• Roll the slicer version back — that is exactly what support suggests for these cases.
• Run the same file through the other slicer and compare: if the settings show real temperatures, the printer is not the problem.
• Keep a known-good version pair and never update the slicer and the firmware on the same evening, or you will not know what broke.
• Profile setup for OrcaSlicer is covered separately in our OrcaSlicer guide.

21. The USB drive is not recognized

The requirements are strict and printed nowhere on the box. Files must use the .gcode extension, names must be Latin letters and digits, and the path must be no deeper than two folders. The drive must be FAT32 with 4096-byte clusters and no larger than 8 GB — the wiki openly admits compatibility trouble with bigger drives. One more trap: the left USB port on the base belongs to the multicolor unit, so the stick goes into another one. Plug in two sticks and only one is read — that is normal, the second port is reserved.

22. After a pause the toolhead crashes into the part

An M600 pause works as expected; resuming does not. The head extrudes, moves to the far left corner and then drives straight through the printed geometry. On large models the impact tears the part off the plate. This is the wrong purge position on resume, and firmware 1.1.2.8 lists exactly that fix in its changelog. Until you update, avoid pausing large prints.

Mechanics, bed and toolhead

23. The toolhead presses into the bed and will not stop: the strain gauge

The Kobra 3 V2 has no separate probe: contact with the bed is detected by a strain gauge in the toolhead. When it fails, homing turns into a crash — the head keeps descending and digs into the plate. On screen that shows as 10130 and 10237.

1. Cool the toolhead below 30 °C, raise Z to mid-travel and start Z homing.
2. Touch the toolhead with your hand while it descends: a healthy sensor makes it rise. If it keeps going down, the gauge needs replacing.
3. Remove the toolhead shell — it is held by clips — unplug the part cooling fan and LED harnesses and reseat the strain gauge connector on the adapter board.
4. Inspect the harness and the gauge itself: damaged insulation or a deformed body means a new assembly, not a settings tweak.

24. Codes 10126, 10127 and 10129: vibration compensation fails

Vibration calibration aborts with an error and the print never starts. The codes split by cause: 10126 is a loose X belt, 10127 a loose Y belt, 10128 a problem with the accelerometer or its wiring, 10129 the harness under the bed. For 10129 the official instruction is exactly one action: inspect the wiring under the bed for looseness or chafing and reseat the cable. If the accelerometer itself dies, prepare to source the part from third-party sellers — owners report not finding it even in the official store.

25. The steel sheet lifts off the magnet at the corners

It looks like ordinary warping, but something else is happening: on parts with a large footprint the shrinkage lifts not the part but the entire spring steel sheet with it — the magnet is not strong enough. Notebookcheck recorded this during testing and solved it with home-made corner clamps, while warning about the risk: heating traces run under a thin layer of lacquer, and a metal clamp can breach them.

• Clamp the sheet only at the corners and only with plastic clips, keeping metal off the printing area.
• Shrink the first-layer footprint: split the part, add a chamfer, use a brim.
• Raise the bed temperature by 10 degrees and remove drafts — cold air from the side cools the sheet unevenly.
• General anti-warping technique is covered in our warping guide.

26. A bed map with a millimeter of spread, and a tilted gantry

The first layer is squished in one place and floating in another, and large parts show bands of thick and thin extrusion. An owner who pulled a height map through the custom firmware measured roughly a millimeter of spread. The second symptom: the X gantry visibly flexes when the nozzle touches down and the left Z side sits lower than the right. Auto-leveling does not cure that — it compensates, but it does not fix geometry.

1. With the power off, rock the toolhead up and down along the X axis. Any play is taken out with the eccentric nut and a 10 mm wrench: the wheels must contact both sides of the rail without spinning free.
2. Check the bed the same way along Y — there is an eccentric there too.
3. Run the official gantry calibration: slacken the belt, loosen the S2.5 screw, press the gantry down onto a spacer and tighten under load.
4. If the geometry is fine and the map is still bad, loosen the bed screws, heat the bed and retighten; in stubborn cases owners add precision shim washers.
5. Use zoned leveling: it probes only the area under the model and cares less about distant corners.

27. The nozzle is glued into the block: replace the whole hotend

That "Kobra S1-grade" seal has a price: the 0.4 mm brass nozzle is threaded into the heater block and glued in place. Tom's Hardware sums up what happens if you try to unscrew it — a broken tip. Anycubic offers 0.6 and 0.8 mm sizes, but in brass only, so abrasive filaments call for a third-party hardened hotend. The good news: the assembly releases with a single latch.

28. A clog when switching from a hot filament to a cold one

Load PLA after PETG and you get a clog that refuses to clear. A printer service technician documented the mechanism: the cutter severs the filament right at the heatbreak joint, the PETG remains inside and simply will not melt at PLA temperatures. The printer honestly reports a clog but cannot push through it while the material profile stays cold. The same happens moving from silk PLA to regular PLA when the temperatures differ noticeably.

1. Before switching materials, heat the nozzle to 250 °C and push the new filament through for three minutes — the official maintenance recommendation.
2. If the clog already happened, temporarily set a high-temperature material profile and clear the remains.
3. Within one multicolor print, order the queue from hotter materials to cooler ones.
4. If clogs repeat regardless of material changes, see our nozzle clogging guide.

29. Slow bed heat-up, and an "overheat" caused by the wrong connector

The 24 V bed has no insulation underneath, and heating from 20 to 60 °C takes over two minutes — a measured figure, not an impression. The second story is shorter and more painful: after a heater swap the printer starts complaining that the bed temperature is too high. One owner ordered two replacement beds before realising he had plugged the heater into the fan socket. Check connectors and the mains voltage selector before you order spare parts.

30. 600 mm/s on the box, 25 mm³/s in reality

The advertised 600 mm/s applies to travel moves. The measured hotend ceiling is around 25 mm³/s with quality intact; at 31 mm³/s gaps appear in the walls. Convert that to a 0.2 mm layer and a 0.42 mm line width and you land near 350 mm/s under ideal conditions. The real working speed that keeps quality is about 300 mm/s, while the Anycubic wiki quotes 350 mm/s at 20,000 mm/s² acceleration. In practice, print outer walls slower than inner ones and do not push travel acceleration: owners specifically complain about knocking noises at 20,000 mm/s².

31. The head cable: codes 11407 and 10131

The printer refuses to start (11407) or reports a nozzle MCU fault mid-print (10131). Both come down to the same thing: a loose or chafed print head cable. The routine: power off, tighten the two cable retaining screws with an S1.5 hex key, remove the bottom cover (two S2.5 screws, unplug the fan) and reseat the cable on the mainboard. Damaged insulation means replacement. And route the tubes and camera cable so they do not tug the harness on every pass.

32. Rust on the rails and wheels

An owner living 50 meters from the sea found rust on the rails and bearings within six months — the thread collected 91 points and three dozen comments, so it is hardly a one-off in humid climates. The community answer is simple: wipe the rails with a lint-free cloth, replace the worn wheel and keep a thin film of oil on the metal. And per the vendor's own schedule: lubricate the Z lead screw every three months with grease specifically, because thin oil runs into the motor and kills it.

A closed ecosystem and what support looks like

The Kobra 3 V2 has a problem all its own: you cannot properly diagnose a failure. Log files are password-protected, the stock interface shows no bed map, and Anycubic Slicer Next trails the OrcaSlicer it is built on by several versions. That is exactly why owners move to custom firmware — not for Klipper as such, but to finally see a height map and some logs.

On warranty, keep two facts in mind. First, parts ship from China and even the success stories take weeks — in the documented case a full replacement took six weeks, though support did send a head cable, a strain gauge and a mainboard. Second, some Ali sellers cover the toolhead and extruder for only three months, so it pays to stock consumables — hotend, nozzle, cutter assembly, tubes — before you need them.

Anycubic Kobra 3 V2 error code reference

The Anycubic reference lists 93 error codes, and most of them have a dedicated page for the Kobra 3 and Kobra 3 V2. Below are the ones owners actually run into.

The full list with per-code walkthroughs lives in the Anycubic reference: the printer shows a QR code next to each error that takes you straight to the right page.

Preventive maintenance by the book

General 3D printing problems

Beyond the Kobra 3 V2 issues above you will also meet the ordinary FDM problems. We cover each one separately and in depth:

• First layer not sticking or curling — Z-offset, plate cleaning, temperatures
• Nozzle clogs — partial clogs, heat creep, cold pulls
• Stringing between walls — retraction, temperature, drying
• Warping and lifting corners — shrinkage, draughts, brim and raft
• Layer shifting and ghosting — belts, acceleration, Input Shaper
• Under- and over-extrusion — flow and step calibration
• How to dry filament — temperatures and times by material
• Printer maintenance schedule — what to check and when

Also worth reading for this machine: 28 mods and upgrades for the Kobra 3 V2, our ACE Pro multicolor guide, the first Kobra 3's known issues for comparison, the Anycubic filament breakdown and a comparison of the whole Kobra lineup. To move printing off the cloud, see our remote access guide.