Timo,
I built the Teensy with an MPC2562 CAN BUS today, I get it to communicate with the NMEA Reader using the static temp values. I hooked up a DS18B20 and get a different readout but not accurate. I can't tell what pin you intended the data to go to. I used what I believe is A0 or pin 14 it is 2 from the end. I loaded a different sketch and the output was -127 which usually means the wrong pin is being used for the data or the probe isn't working.
Thoughts on that?