Wrong temperature on extruder 2 Firstly, I just bought a G2S mini pro from Geeetech and it is my first 3D printer (therefore I'm 100% newbie in this area).

The first extruder seems to be ok, the temperature varies from 23°C to 201°C and if you touch it you can see that it is hot. However, for the second extruder, the temperature is shown with more than 400°C:



The cables are connected correctly and the firmware is updated. 

Do I have to return the printer? Or is there another solution?
If you have access to an IR thermometer, it would be interesting to verify what the actual temperature is.  I doubt the hot end actually reaches that temperature, but:


if it actually does, then it could actually be dangerous, as most extruders are designed for temperatures well below 300°C.  The problem would likely be in the firmware in this case.
if it stays cold, then probably is a problem with the temperature probe or its cables/connectors being broken. Most printers use thermistors as temperature probes, and thermistors let less and less current pass through the higher the temperature is, so: no current would be interpreted as the hot end being "extremely hot" and the firmware would not heat the hot end further.
if it is hot but at another temperature than the one displayed, then it could either be a problem with the probe over-reading or a firmware bug (e.g.: the temperature is shown in Fahrenheit, or the firmware mis-process the signal from the probe).


Either way: thermistors and cables are cheap to replace, while problems with the firmware may be fixed only if you have access to the code.

If you just bought the printer in a physical store, I would simply swap it with another unit, rather than fiddling with it, though.