Auto start stop router function troubles

Hi all just a quick question for you all … I have the metal maslow kit and have it all up and running well NOW… but was just wondering about auto start stop function. Tried at the start to get it working but there was a few more important thing to get running first so left it go but would like get it working now with your help if possible…When i put the command M04 straight into GC it does not activate the router but if put in a different command G00 Z10 it will rise the router… so could be that it is not turn on in the firmware any help would be much appreciated