emaxx brushless problems

I have a mtroniks brushless system in it and it was working great. and for some reason when i turned it on to go drive it again it had like no power. it was goign at about rock crawler speeds. so i checked if the batter was even charged and it was putting out 15volts (4 cell lipo) so it was good. i then put a bec on it casue i was never running a bec. and that did nothing. i then tryed to swap out the motors and it still ran the same. Also i thought it might of been cause the lipo had not been balanced the last time i charged it and i have not really used it for a few months. so i hooked it on the balancer and it started to balance and when it was done i turned it all on and it was the same. the only things i have not tryed yet is the esc and radio. i was playing with the radio trying to make it not brake so hard but when i was going over the setting on it it was all fine. so im guessing it was the esc.

just wondering what you guys think and if u know of something else i should try.

if i had another esc i would try it but i dont.