Don't know right off the bat, however there are a few things you can do.....try zapping the pram (reboot computer, hold down Apple, Option, P and R keys for 3 chimes) then let go....resetting the SMC...shut down computer, plug in power adapter, on left side of keyboard hold down Shift, Control, Option and power button for 30 sec then let go and then press the power button.* Is this a recent problem, or has it been going on for some time. I don't know what OS you have so can't help you a whole lot, also, see if there's a recall program for your particular model and year of Macbook pro....oh sorry, looks like it's ended...darnit.....you may want to consider booking an appointment at your local Genius Bar and taking it in for a checkup
good luck to you
John B
* not super sure about that, so you may want to check Apple's support page for how to do that......