P0328 Mazda - i want to know how much it cost a replacement.

Question

1500 cc
mazda verisa
2006
i saw engine check sign on 30/4/2014 at 12.30 p.m
but when i restart it after 20mins break, its gone.
but it was appeared again while i was driving.
i want to know how much it cost.
how much cost to repair this.