MacBook cannot go to sleep

My MBPR 13" late 2012 cannot go to sleep. Either when I close the lid or left it to sleep automatically with the energy saver mode, the screen goes blank but the computer itself keep working and the laptop is quite warm. Left it for several hours on the (faulty) sleep mode and the battery goes to 0%. I am sure this is not software problem, already try to reset the SMC, clean install and upgrade to Yosemite, the problem is still exist.

The problem occurred after I brought it to apple authorized service centre to replace the loosen HDMI port. The service centre cannot found any problem on this cannot sleep issue :(

Is it because of hardware problem, like faulty sleep sensor hardware?

Thank you in advance for your help.