A personality component is a part of a Transformer's anatomy that governed their personality without which they would be a dumb almost zombie like mechanoid. They could be removed an criminal's structure and placed in a detention center where they resembled an Energon Cube.
Fiction
Generation 1 cartoon continuity
In Starscream's attempt at forming his own army to overthrow Megatron, he journeyed to Cybertron where he liberated the personality components of the Renegade Decepticons. Starscream's Brigade
After selling his fellow Combaticon parts, Swindle had a bomb placed in his head and ordered to reassemble his comrades by Megatron or be destroyed within 15 hours. Swindle managed to get all the Combaticon parts except Brawl's personality component. He didnt think it would matter and was disappointed to find that they could not merge into Bruticus... Megatron was not amused.... B.O.T