how do I fix a p0447 code? land rover discovery / please help!!

Question

hey guys I have a 2000 land rover discovery and about 2 days ago it started to shut off on its on . also when it heats up it wont start until its cooled down which is in several hours . recently changed oil and spark plugs . it read a code p0447 and want to know how I can fix it. I also heard that it could be the crank shaft sensor . please help me guys . I don't want to spend hundreds on of dollars by taking it to the dealer.

                                                  any idea???
                                                              -Alexandra