Two t
1. Some PSU (Power Supply) do not have -12V output anymore
  because the new MBs do not use it. You'd better yr PSU label
  first whether there is any -12V output.
2. There may be errors on the part of the sensor (on the M/B)
or the software does not support certain type of sersors.
  You'd better check the voltage readings in BIOS.
  Software readings are not reliable. Do not rely on them.