# My printer keeps shutting down, need help with debug **URL:** \ **Category:** General Discussion\ **Created:** [February 21, 2025, 11:35pm UTC](https://klipper.discourse.group/t/my-printer-keeps-shutting-down-need-help-with-debug/22139 "2025-02-21T23:35:31Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![SpikeyGG](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/spikeygg/32/3993_2.png) [@SpikeyGG](https://klipper.discourse.group/u/SpikeyGG)\ **Post date:** [February 21, 2025, 11:35pm UTC](https://klipper.discourse.group/t/my-printer-keeps-shutting-down-need-help-with-debug/22139/1 "2025-02-21T23:35:31Z")
### Basic Information: Printer Model: Voron 2.4 MCU / Printerboard: BTT Octopus Host / SBC: Raspberry Pi 4 klippy.log: [klippy\_failure.log](https://klipper.discourse.group/uploads/short-url/fYonkSUuZULeavaJLgCkPh24pC6.log) (366.7 KB) ### Describe your issue: I was in two hours into printing a 5.5 hour print yesterday and my printer stopped, I was at work during the failure. When I got home, I checked the log and couldn’t find anything meaningful. I restarted klipper and it came back online, I tried to do a home X and it got halfway to the X-endstop and then stopped again. I checked the log and the most meaningful thing I could find was: `Lost communication with MCU 'sb2209'`. At this point, I couldn’t get klipper to come back. I tried restarting klipper, all the other services, even rebooting the pi wouldn’t bring it back online. I let it sit until today. I decided to start the debug, I turned the system off again and turned it back on and when it came up, to my surprise, klipper came back online. Sorta bittersweet because now I know it’s intermittent for sure! Anyway, I heated up the hotend so I could unload the filament, that all worked (via ERCF `MMU_UNLOAD`, which moves the syncronized gear with the extruder to unload the filament). I let the hotend cool down. I then attempted a home ‘X’ which worked, then attempted a home ‘Y’ and it failed – that’s the attached `klippy.log`. This log also has a `Lost communication with MCU 'sb2209'`. Does this mean I have a bad board, bad cabling, something like that? I’ve used the printer like this for probably over a hundred prints, so it is disappointing to be having this intermittent issue all of a sudden. I started to get some `Undervoltage detected` warnings just before this failure (and they were happening when the printer was idle: nothing was hot, motors not energized) and I’m not sure if that is related to this issue or not… I think I need to measure my supplies and make sure they’re in spec. Is there any additional detail that can be gleaned from my log file? Any other ideas of things to try to figure out where the issue lies? ---
**Author:** ![nefelim4ag](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/nefelim4ag/32/2387_2.png) [@nefelim4ag](https://klipper.discourse.group/u/nefelim4ag)\ **Post date:** [February 21, 2025, 11:52pm UTC](https://klipper.discourse.group/t/my-printer-keeps-shutting-down-need-help-with-debug/22139/2 "2025-02-21T23:52:43Z")
Well, according to logs, both `sb2209` and `scanner` show timeout, at the same time. ```auto Timeout with MCU 'sb2209' (eventtime=622.707328) Transition to shutdown state: Lost communication with MCU 'sb2209' Timeout with MCU 'scanner' (eventtime=622.707328) ``` So, looks like a CAN wiring/power issue. Btw, sounds similar to [New Voron instance lost communication with EBB (can bus)](https://klipper.discourse.group/t/new-voron-instance-lost-communication-with-ebb-can-bus/22104) Hope it helps. ---
**Author:** ![SpikeyGG](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/spikeygg/32/3993_2.png) [@SpikeyGG](https://klipper.discourse.group/u/SpikeyGG)\ **Post date:** [February 22, 2025, 12:17am UTC](https://klipper.discourse.group/t/my-printer-keeps-shutting-down-need-help-with-debug/22139/3 "2025-02-22T00:17:33Z")
> [@nefelim4ag](#): > > So, looks like a CAN wiring/power issue. Yeah! I think you’re right. I started looking at the `bytes_retransmit` and `retransmit_seq` counts in the “MCU Information” reporting and the SB2209 and Cartographer boards were both reporting more than zero and seemed to be incrementing while the toolhead was moving for home operations. It turns out that I have a spare CANbus umbilical cable that I created so I took the existing one off and replaced it with my spare. After doing that I restarted klipper and I could home all axes and run QGL. I was watching the `retransmit` values like a hawk while doing all of this and it, so far, has stayed at zero. I’m going to try kicking off a print and see if it completes and I’ll keep an eye on the `retransmit` values. 🤞 Thank you for looking and offering help!! I’ll read the other thread and see if I can use anything from there, as well. ---
**Author:** ![SpikeyGG](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/spikeygg/32/3993_2.png) [@SpikeyGG](https://klipper.discourse.group/u/SpikeyGG)\ **Post date:** [February 22, 2025, 6:31am UTC](https://klipper.discourse.group/t/my-printer-keeps-shutting-down-need-help-with-debug/22139/4 "2025-02-22T06:31:58Z")
Well, I was able to complete my 5.5 hour print completely without issues tonight after swapping the cable so I think it was something to do with that other one. ---
**Author:** ![system](https://global.discourse-cdn.com/free1/uploads/klipper/original/1X/64419bf2aac6639e6ef5cef200dcd456b0a01ac3.png) [@system](https://klipper.discourse.group/u/system)\ **Post date:** [March 24, 2025, 4:32pm UTC](https://klipper.discourse.group/t/my-printer-keeps-shutting-down-need-help-with-debug/22139/5 "2025-03-24T16:32:55Z")
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