<p>I solved this issue by using a multimeter to measure the resistance across both the thermistor and the heater cartridge. The resistance for the Ender 3 Pro are:</p>
<ul>
<li>Thermistor ~ 100k ohms</li>
<li>Heater Cartridge ~ 14.4 ohms</li>
</ul>
<p>My thermistor showed a resistance within the correct value, however my heater cartridge had a resistance of 0 ohms.</p>

CC BY-SA 4.0
2021-11-21T22:34:36.203Z
2021-11-21T22:34:36.203Z
Tim Powell
<p>My Ender 3 Pro started throwing the Thermal Runaway E1 error last week. Previous to that I had not modified or changed anything on the printer in months, other than move it's location. I replaced the thermistor yesterday and set off a test print but got the same error.</p>
<p>Is this an issue with the motherboard? Or with the heater cartridge?</p>
<p>Printer specs:</p>
<ul>
<li>Ender 3 Pro</li>
<li>Creality 4.2.7 silent motherboard</li>
<li>all metal dual gear extruder</li>
<li>Glass bed</li>
<li>stock everything else</li>
</ul>

CC BY-SA 4.0
2021-11-14T12:14:59.067Z
conditions are hard to replicate at times - is the same g-code triggering it? is it only happening on warm or cold days? when the window is closed?
Trish
CC BY-SA 4.0
2021-11-14T13:29:39.760Z
temp reading increases despite shutting off heating element... could you be running a bit too much current through the thermistor? could the A to D converter be failing? could something be acting as a big thermal mass between the heating element and thermistor?
Abel
CC BY-SA 4.0
2021-11-14T13:56:22.407Z
Most likely cause of this is the wire between the thermistor and the board being fatigued with a partial break and giving random bad readings.  Did you replace the wire when you replaced the thermistor?
user10489
CC BY-SA 4.0
2021-11-14T13:57:38.910Z
If I turn on my heated bed, and then lift the bed off the plate and put it back down, I get the thermal runaway error.  Any sudden temperature change caused by external events can trigger this.  However, I assume that this isn't the cause in this case; it is something to think about.
user10489
CC BY-SA 4.0
2021-11-15T10:35:03.387Z
@Trish - I have created some new g-code using the same model and it is still happening. Sometimes it occurs after minutes, sometimes after hours. The conditions of the room stay consistent and the window doesn't get opened.
Tim Powell
CC BY-SA 4.0
2021-11-15T10:35:07.280Z
@Abel - how can I test the converter? It is a standard hot end.
Tim Powell
CC BY-SA 4.0
2021-11-15T10:36:26.890Z
@user10489 - Yes I replaced the wire and thermistor in one. It was a pre-made pack for replacing thermistors in 3D printers.
Tim Powell
CC BY-SA 4.0
2021-11-15T23:18:04.733Z
to test the a2d hook up a potentiometer of appropriate value where a thermistor would go and check the temp readings against the pot resistance.
Abel
CC BY-SA 4.0
2021-11-20T01:52:00.977Z
It could be wrong themistor model you use. Some thermistors need to have 100k resistance at 25 Celcius degrees. Also mother board componets might be damaged aswell but before going that deep try to buy the correct thermistor model and install it without harm and short circurit.
Sami Onur Zaim
<creality-ender-3><troubleshooting><thermal-runaway>
Sporadic thermal runaway E1 error on Ender 3 Pro, continues after thermistor replacement. What could be the cause?
Tim Powell
# Sporadic thermal runaway E1 error on Ender 3 Pro, continues after thermistor replacement. What could be the cause?

(Asked by: username_0 on 2021-11-14)

My Ender 3 Pro started throwing the Thermal Runaway E1 error last week. Previous to that I had not modified or changed anything on the printer in months, other than move it's location. I replaced the thermistor yesterday and set off a test print but got the same error.

Is this an issue with the motherboard? Or with the heater cartridge?

Printer specs:

* Ender 3 Pro
* Creality 4.2.7 silent motherboard
* all metal dual gear extruder
* Glass bed
* stock everything else

**Tags:** creality-ender-3, troubleshooting, thermal-runaway

> **Comments:**
> **username_1**: conditions are hard to replicate at times - is the same g-code triggering it? is it only happening on warm or cold days? when the window is closed?  
> **username_2**: temp reading increases despite shutting off heating element... could you be running a bit too much current through the thermistor? could the A to D converter be failing? could something be acting as a big thermal mass between the heating element and thermistor?  
> **username_3**: Most likely cause of this is the wire between the thermistor and the board being fatigued with a partial break and giving random bad readings.  Did you replace the wire when you replaced the thermistor?  
> **username_3**: If I turn on my heated bed, and then lift the bed off the plate and put it back down, I get the thermal runaway error.  Any sudden temperature change caused by external events can trigger this.  However, I assume that this isn't the cause in this case; it is something to think about.  
> **username_0**: @username_1 - I have created some new g-code using the same model and it is still happening. Sometimes it occurs after minutes, sometimes after hours. The conditions of the room stay consistent and the window doesn't get opened.  
> **username_0**: @username_2 - how can I test the converter? It is a standard hot end.  
> **username_0**: @username_3 - Yes I replaced the wire and thermistor in one. It was a pre-made pack for replacing thermistors in 3D printers.  
> **username_2**: to test the a2d hook up a potentiometer of appropriate value where a thermistor would go and check the temp readings against the pot resistance.  
> **username_4**: It could be wrong themistor model you use. Some thermistors need to have 100k resistance at 25 Celcius degrees. Also mother board componets might be damaged aswell but before going that deep try to buy the correct thermistor model and install it without harm and short circurit.  

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## 1 answers

### Answer by username_0 on 2021-11-21. Score: 2 | Accepted answer

I solved this issue by using a multimeter to measure the resistance across both the thermistor and the heater cartridge. The resistance for the Ender 3 Pro are:

* Thermistor ~ 100k ohms
* Heater Cartridge ~ 14.4 ohms

My thermistor showed a resistance within the correct value, however my heater cartridge had a resistance of 0 ohms.


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