bmw x5 2005 electrical problem

[skrewcop]

Ok so i checked the voltage with the cluster when the engine was pretty warm and it wasn't that cold outside either. With the engine off it fluctuates between 12.1v to 11.9v sometimes and when i turn it on it's somewhere between 13,7-13.9v. These readings show when there's no warning light in the dasboard and no "trans. Failsafe. Progr". I checked the voltage this morning with the engine cold and -4*C outside and when i turned it on it went to trans failsafe program as it usualy does on the first start and as soon as the ABS light comes on, the voltage goes up to 16.9v and drops to 13.7-13.8v when the light dissapears and so on for 5 minutes. Could it be the voltage regulator or i'm having transmission issues? Thanks a lot