Zero point

In order for a Transformer to function, the energy from their spark has to flow through their entire body, making contact with all their components and turning them from inanimate bits of metal into the body parts of a living being. However, certain injuries to the head or chest can open up a zero point, a microscopic gap in the spark's flow that prevents it from making its vital journey around the body and puts the victim in a comatose state, leaving them unconscious as their body slowly dies from the dwindling contact with their spark. There are no known medical means to detect or repair a zero point, and though there are rare cases of patients recovering, nobody can explain how or why these miracles occur.

Fiction

2005 IDW continuity

Thought both undetectable and untreatable, a zero point was heralded by medics being able to detect only two of a spark's five frequencies. The Return of the King

Ultra Magnus was one of the few who once recovered from a zero point. (Or did he??)

Springer was left in a coma after his battle with Overlord resulted in a zero point appearing in his body, and medics Fixit and Kaput were unable to wake him even after a full body refit. Kup then got help from the psychiatrist Rung, who offered a theory that triggering certain emotional responses in Springer's brain might cause him to subconsciously force his spark across the zero point, healing it in the process. On his suggestion, Roadbuster began reading Wreckers: Declassified datalogs to the unresponsive Springer in hopes that he'd remember his experiences in the Wreckers and recover. It seemingly had no effect until Springer's painful memories of Impactor and Pova surfaced, at which point he began showing signs of life again. Zero Point

In the centuries he'd spent trapped in the Functionist Universe, Megatron trained to become a medic, eventually amassing the skills needed to casually treat zero points, using this knowledge to save Drift's life after the Autobot had been shot through the chest by the Grand Architect's troops. The Return of the King