Module reports external temperature when no sensor is connected


I have one “special” Cell module. It think’s that an external temp sensor is connected.
Reconnecting to the Battery or reflashing didn’t fix it.
It will be replaced now with a spare board.

How can I do some further investigations on this behaviour?

Is it maybe Attiny internal?

I have also had such a problem, if your module is v4.21 version, check your R21 resistance welding situation, false soldering will occur! The power supply of the module must be disconnected for welding! Caution!

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  • Check the sensor1 holes - pins 1 and 2 for solder bridges
  • Check soldering on R21
  • Check solder on ATTINY pin 2

If you have a multimeter, check resistance between ATTINY pin 2 and ground - it should be 47k ohms

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R21 looks good, but solder of Pin2 of Attiny was it,

Thank you for guiding in the right direction