Ender 3 Pro - 4.2.7 - CR Touch - Heating Failed


I was previously using the Creality firmware before upgrading to the 7/6 Ender 3 - v4.2.7 Board - BLTouch with no heating issues. I’ve done the onboard PID tune several times but I am getting a string of “Heating Failed, Please Reset” errors when attempting to print. Any idea what’s wrong? It seems that once it heats fully once it will work again until the machine is reset. Once reset the heating errors return until a successful heat then I can print back to back again.

Reset your EEPROM to factory defaults, save the defaults to the EEPROM and restart your printer.

Set it up again, and you should be able to save your preferences without issue.

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The new PID values set correctly after the tune but the “cold start” heating failed issue remains. Do you still suggest doing a EEPROM reset?

Yes. Likely something stored in the EEPROM structure is incompatible between major versions of Marlin.

This appears to have fixed the issue, 3x cold start heat cycles and no errors. Thank you for your work and assistance.

Unfortunately this morning heating errors are happening again. It gets within 7-8deg of the target temperate then drops back 5-6deg then when its heating back up it throws the error.

Here are some more values that might help diagnose this as it seems like its the PID values are not working as intended.

[Old Marlin 1.X Firmware]
Target Temp: 200

Heats up quickly to about 197, then slow creep to 202, then cool down to 200 and the print begins.

[New Nightly 2.1.x Firmware]
Target Temp: 200

Heats up fast until 193, drops back down to 188, slow creeps to 191-193 then throws heating error 70% of the time. Sometimes it will slow creep all the way to 200.

To me it seems like the PID settings are not applying enough power towards the end of the heating cycle and reducing temp too early then throwing an error too quickly.

Also a related observation, once there is a successful heat up I do not experience any further errors until the machine is turned off and back on. I have better luck using the Preheat PLA End than I do kicking off a print job for heating successfully, both set to 200 print temp. This is happening on two separate Ender 3 Pros with upgraded 4.2.7 mainboards.

I don’t know enough about PID or firmware to correct any of these observations but maybe it will help understanding what is happening.

This Marlin bug report seems to describe the same issue I am experiencing:

Have you done a PID Tune using the auto-tune?


I am looking at changing the hotend control algorithm on the nightlies from PID to MPCTEMP - which seems to work MUCH better… However it will have the side effect of people not understanding the change :expressionless:

I have used the Auto-tune control via the printer interface but not through a computer. I’ve been playing around with manually adjusting values all night and I’ve got it to consistently heat up now but the temp bounces around too much so I’m still tweaking.

I was reading about MPCTEMP on marlinfw earlier and it sounds way more accurate.

That should be the same. Just for a sanity check, I’d double check the connection between the heatblock and the thermistor, and the thermistor cable going to the mainboard - make sure something hasn’t come loose.

It’d be annoying if it was something so simple…

I checked that last night on the connections, all good there. Any chance of increasing the PID tune cycles to 10 instead of 5?

Sorry for the late reply…

This is normally done via the GCode command - you can set the cycle count to any number you wish.

This thread did jog a memory though - if you don’t have the silicon sock fitted to the heat block, this can be a common problem. The sock is to prevent excessive heatloss via the part fan as it blows on the block.