Thank you for your quick response.

I changed every wire and even tried it with another sensor - still the same problem.
The voltage at the pi is 3.3V. I noticed that the problem occured after I changed the pull-up resistor of the 1-wire bus from 4k7 to 2k2 (before that everything worked as intended).

Is there any intern pull-up resistor that I need to change or turn off/on?

Hello guys, I have a problem regarding my BMP180 sensor.
When I restart my Pi everything is fine: I can see my BMP180 on my I2C bus (using i2cdetect) and the scripts I made work as intended.

After a few minutes though, my BMP180 suddenly disappears from my I2C bus and the scripts return an I/O error.

Can anyone help me? Thanks in advance!