tc and hd light

Hi Guys, Mr Newbie again.
I have a 52 plate td4, and occasionally the Traction control light and the hill descent warning light are coming on together.
What does this mean?
Hill descent is not active and the lights go off after a few minutes.
Should I be worried or is there a simple fix to this issue.
Many thanks in advance.
Nigel

try a search, it's been answered countless times