- A Defense Matrix is a Transformer body system in the G.I. Joe vs. the Transformers portion of the Generation One continuity family.
The Defense Matrix is a Transformer's electronic autoimmune system. It can respond to nonphysical intrusion with countermeasures, tailored computer viruses, and reflexive distress signals broadcast by any available means. The Defense Matrix functions at a level below conscious control, and it makes any attempt to 'hack' a Transformer very hazardous, at least from a non-isolated computer.
Wheeljack's responses indicate the Defense Matrix is part of every Transformer, and it is apparently not related to the Matrix of Leadership. The name is just another way of making Transformers unnecessarily confusing.
G.I. Joe vs. the Transformers continuity
Dr. Mindbender's attempts to bend the captive Optimus Prime to his will triggered a response from his Defense Matrix, which invaded the Cobra computer system and sent out several hundred random e-mails detailing his location and situation before it could be shut down.