ime back and i need help i have a engine management light on code po16

ime back and i need help skoda fabia 1.2 12c htp engine i have a engine management light on  code po16 on a cheap odb reader  it says timing sensor problem the car has done 140 k i have had a bit of a rattle for a cpl of seconds when its cold my instinct its the timing chain again i belive its a known fault i have looked on yt and i thing the job is doable how do i lock the crank are them lazer knockoff tools ok and advice thoughts will be gladly recieved