How to get past the grunt at mt.coronet in pt?

Question

he sas he has no Pokemon

Answer 1

Asked before. http://pokemondb.net/pokebase/85620/how-you-get-the-galactic-grunt-move-the-top-coronet-platinum

Return there after defeating the Elite Four. Inside that cave lies TM02 Dragon Claw.

- Mew

Answer 2

Well you can actually get there before the elite four.
I got there when I had defeated the eight gym.