A team always has a bad member, a least experienced player, a weakest link. Hi-Test is that weakest link. Among Soundwave's group of Mini-Con subordinates, Hi-Test doesn't succeed as the others do as he is banished. Its not that he's dumb, its just he lacks the skill in thievery his teammates have. Sadly for him, Soundwave is not having it.
Sometimes, he works with a much better boss: Optimus Prime.