<p>The most probable reason that this error is generated immediately after you power on the 3D printer is that <strong>the thermistor (temperature sensor of the heated bed) is shorted</strong>. You are advised to check the cables or replace the thermistor with an appropriate alternative sensor.</p>
<p>If a thermistor is short-circuited, meaning it effectively has zero resistance, the behavior it reports to a microprocessor monitoring it will depend on the type of thermistor and how the temperature measurement is set up.</p>
<p>Generally, the type of thermistor used in 3D printing is the <strong>Negative Temperature Coefficient (NTC) thermistor</strong>. This is the most common type where resistance decreases as temperature increases, a short circuit (zero resistance) would be interpreted as an extremely high temperature. This is because the monitoring circuit (typically involving a voltage divider or a similar setup) would read the low or zero resistance as indicative of very high temperature conditions. This would trigger the bed temperature error.</p>
<p>E.g. for a <strong>Positive Temperature Coefficient (PTC) thermistor</strong>, where resistance increases with an increase in temperature, a short circuit would not align with the typical behavior you have described. However, since short circuits effectively bypass the thermistor, the system could be designed to recognize this as an error condition rather than a temperature reading.</p>
<p>In either case, sophisticated microprocessor-based systems often incorporate error handling to detect and respond to such faults. If the system recognizes the resistance reading as abnormally low (or zero), which is outside the expected range for operational temperatures, it might trigger an error or fault condition rather than reporting an actual temperature. This helps in preventing incorrect actions based on faulty sensor data. Therefore, rather than reporting an extreme temperature, the microprocessor might indicate a sensor failure or a circuit error.</p>

CC BY-SA 4.0
2024-04-18T16:41:02.787Z
i checked if power was going to the mother board it did but when i checked if it as going to the bracket where the brackets hold the wires for the bed and hot en it stayed zero
caleb stahl
CC BY-SA 4.0
2024-04-18T08:28:53.053Z
2024-04-18T08:28:53.053Z
0scar
<p>I had problems with my extruder and while I was fixing it, this came up on the screen and it started beeping (I shut off the 3D printer and started it again but it still came up on the screen):</p>
<pre><code> ***ERR: MAXTEMP: BED PLEASE RESTART*** 
</code></pre>
<p>If I turn on the 3D printer (turn on the power) it should take you to the home menu where all the settings are: like preheat PLA/ABS, motion auto home and disable steppers, etc., but instead, the error appears immediately and it starts beeping.</p>
<p>Would someone know what is wrong?</p>

CC BY-SA 4.0
2024-04-17T13:24:00.573Z
Hi and welcome to 3DP.SE! You need to be a little more descriptive to solve this issue. Do you see this when you turn on the printer, or when you warm up the printer. If so what do you do and what do you see? Have you seen this: https://www.youtube.com/watch?v=BDj8sVS3YNI?
0scar
CC BY-SA 4.0
2024-04-17T16:48:05.537Z
It apeared while it was running and i was preheating the bed  so i turn it completly of i then turn it back on but it still popped on the screen
caleb stahl
CC BY-SA 4.0
2024-04-17T21:45:48.170Z
The strange thing is that message cannot be found in the Marlin sources; the error message string must have changed by now as you are probably running an older firmware version, or, it is a Creality special containing that specific message. The message tells you that the maximum temperature has exceeded the maximum allowable value, this is 120 °C for the Ender I believe. This implies that the plate is getting too hot, what presets are you using?
0scar
CC BY-SA 4.0
2024-04-17T23:41:51.857Z
If i turn on the 3d printer ( turn on the power ) it should take you to the home menu where all the settings are like preheat pla/abs, motion auto home and disable steppers   are but in stead the err apears and it starts peeping
caleb stahl
CC BY-SA 4.0
2024-04-18T08:29:54.587Z
I think the most probable cause is a short of the bed temperature thermistor, I have added an answer with more information why this could be the culprit!
0scar
<creality-ender-3><heated-bed><temperature>
Ender 3 printer shutting down with "MAXTEMP BED" error
caleb stahl
# Ender 3 printer shutting down with "MAXTEMP BED" error

(Asked by: username_0 on 2024-04-17)

I had problems with my extruder and while I was fixing it, this came up on the screen and it started beeping (I shut off the 3D printer and started it again but it still came up on the screen):
 ***ERR: MAXTEMP: BED PLEASE RESTART*** 

If I turn on the 3D printer (turn on the power) it should take you to the home menu where all the settings are: like preheat PLA/ABS, motion auto home and disable steppers, etc., but instead, the error appears immediately and it starts beeping.
Would someone know what is wrong?

**Tags:** creality-ender-3, heated-bed, temperature
> **Comments:**
> **username_1**: Hi and welcome to 3DP.SE! You need to be a little more descriptive to solve this issue. Do you see this when you turn on the printer, or when you warm up the printer. If so what do you do and what do you see? Have you seen this: https://www.youtube.com/watch?v=BDj8sVS3YNI?  
> **username_0**: It apeared while it was running and i was preheating the bed  so i turn it completly of i then turn it back on but it still popped on the screen  
> **username_1**: The strange thing is that message cannot be found in the Marlin sources; the error message string must have changed by now as you are probably running an older firmware version, or, it is a Creality special containing that specific message. The message tells you that the maximum temperature has exceeded the maximum allowable value, this is 120 °C for the Ender I believe. This implies that the plate is getting too hot, what presets are you using?  
> **username_0**: If i turn on the 3d printer ( turn on the power ) it should take you to the home menu where all the settings are like preheat pla/abs, motion auto home and disable steppers   are but in stead the err apears and it starts peeping  
> **username_1**: I think the most probable cause is a short of the bed temperature thermistor, I have added an answer with more information why this could be the culprit!  

---

## 1 answers

### Answer by username_1 on 2024-04-18. Score: 0 | Accepted answer

The most probable reason that this error is generated immediately after you power on the 3D printer is that **the thermistor (temperature sensor of the heated bed) is shorted**. You are advised to check the cables or replace the thermistor with an appropriate alternative sensor.

If a thermistor is short-circuited, meaning it effectively has zero resistance, the behavior it reports to a microprocessor monitoring it will depend on the type of thermistor and how the temperature measurement is set up.

Generally, the type of thermistor used in 3D printing is the **Negative Temperature Coefficient (NTC) thermistor**. This is the most common type where resistance decreases as temperature increases, a short circuit (zero resistance) would be interpreted as an extremely high temperature. This is because the monitoring circuit (typically involving a voltage divider or a similar setup) would read the low or zero resistance as indicative of very high temperature conditions. This would trigger the bed temperature error.

E.g. for a **Positive Temperature Coefficient (PTC) thermistor**, where resistance increases with an increase in temperature, a short circuit would not align with the typical behavior you have described. However, since short circuits effectively bypass the thermistor, the system could be designed to recognize this as an error condition rather than a temperature reading.

In either case, sophisticated microprocessor-based systems often incorporate error handling to detect and respond to such faults. If the system recognizes the resistance reading as abnormally low (or zero), which is outside the expected range for operational temperatures, it might trigger an error or fault condition rather than reporting an actual temperature. This helps in preventing incorrect actions based on faulty sensor data. Therefore, rather than reporting an extreme temperature, the microprocessor might indicate a sensor failure or a circuit error.

> **Comments:**
> **username_0**: i checked if power was going to the mother board it did but when i checked if it as going to the bracket where the brackets hold the wires for the bed and hot en it stayed zero  

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