Here is the Canon service advisory.
Most likely not your problem. Repair required. Balance repair quote against cost of new body from a reliable source like Keh.com
"Not sure how it would get overheated?"
That was just a thought not a diagnosis. As a concern some 70D cameras have experienced. SOmetimes electronic gear just fails. When you get your estimate, remember another used but working 70D is around $350 to $400 bucks. Also, keep in mind a 70D has got to be nearing end of service life. Perhaps an upgrade in camera is a good notion at this point.