Hi i'm new here and would like some help. i keep getting the dreaded P0487/P0488 fault codes. i have changed both the EGR valve and throttle housing, cleaned the egr cooler, new down pipe to manifold from cooler and today i got a terraclean done on it. i'm thinking it could be a break in the wire but i'm unsure how to test it? also there is air coming back through the air intake that sounds like an atmospheric dump valve. anybody else had the same experience or know if this is normal???? there's no turbo whine but could it be a faulty wastegate actuator?

thanks in advance