Aporte original por: Craig Nagy ,
I had the exact same problem a while ago, and fixed it relatively easily. The problem in my case was that I was using an aftermarket power cord/supply that provided the wrong wattage. Your computer should be using an 85W supply (based on [https://support.apple.com/en-us/HT201700|this link from Apple]). Check the power brick to see if you may be using a 60W supply, like I was. Replacing it with an 85 Watt one should fix the problem if this is it. If that doesn't work, check out [http://forums.macrumors.com/threads/smc-issue-on-mbp-13-hardware-troubleshooting-guide.1122338/|this link] where there is a long discussion about fixing this problem.