8 TDC - top dead centre sensor

well to make a long story short im tryin to purchase a new car and it had a CEL asked the owner if i could check it and it turned out it was throwing #8.. called my buddy that in a actual tech at honda and he doesnt know how to fix it off the top of his head but he knows what it does..

my question is how would you fix the probelm to get rid of the CEL.. or is one of the pistons just totally bad and i should jst forget about buying it..

im not a noob.. i didnt search and nothing turned up as for as how to fix it.. thanks for the help