Heating Failed: E1 error with M175

My M175 toolhead oh my Mini 2 gives me a “heating failed: E1” error when I try to heat it up. The SE toolhead works fine, which makes me think it’s the toolhead. I took the fan shroud off and all the connections looked fine, nothing loose or damaged. Not sure what to look for next, any help would be appreciated.

M175, or M175v2?

Did you change the toolhead in the toolhead menu on the machine? If it’s using the PID settings for the wrong toolhead, it will almost certainly overshoot the desired temperature and trigger an error.

What is the temperature reported on the display before you try heating? if it’s 0 - bad thermistor or bad thermistor connection.

Does the reported temperature show it is heating up at all when you try and heat it up? If it stays at room temperature (20-30c) and shows no change within a few seconds of trying to heat up - probably a bad heater block or heater wiring. If it shows change and is overshooting the target temperature - probably just a PID autotune is required, or you have the wrong toolhead selected (which would be giving it the wrong PID settings).

M175v2. The correct toolhead is selected on the machine, looks like it’s not heating at all - temp waffles between 21 and 22 C.

Previously it had been giving me thermal runaway errors, so I put the SE on until I could get around to looking at the M175. I took off the fan shroud, looked at the wiring, everything looked pretty normal to me. Sounds like maybe the heater block or wiring is the culprit, then?

Yes, I’d start with the heater block. They’re cheap enough that having a spare on hand is common sense. [edit - not the block, just the heater. I blame autocorrect.]

Just unplugging and checking the resistance from the harness should let you know if it’s broken. I can’t tell you what the resistance should be exactly, but an open circuit or short circuit should be obvious. Give the wires a bit of a wiggle while you test to simulate the moving printhead.

Is the heater block the thing that is attached to the wiring harness in these instructions? OHAI: Open Hardware Assembly Instructions
I don’t see it listed separately on the Lulzbot store.

Sorry, not the heater block. I think autocorrect filled in the second word without my consent. Just the heater.


I don’t think they’re anything really special, but you get them from sliceengineering: 50W 3D Printer Heater Cartridge (24V/12V Variations) – Slice Engineering

I haven’t had to replace one yet, so I don’t know if they’re the same size as the standard 50w heaters you can buy for just a couple bucks each.

Thanks! I’ll give it a shot.