On the PW4000 (94") and CF6-80C2 FACEC engines, the EEC will limit the engine in the "Normal mode" for 3 parameters: N1 & N2 overspeed, and "Overboost", which is PS3 pressure. PS3 is "pressure, static, station #3", which is to say the outlet of the high pressure compressor, or if you prefer, the inlet to the combustion chamber. If memory servers, the actual pressure is in the 475-500 psi range for both engines.
In the "Alternate mode", which is "N1" for PW, and "Reversionary" for the CF6, overboost protection is lost, leaving you with only N1 & N2 overspeed protection.
Note that neither engine protects for EGT.
One last thing, I would suggest that you could say a FADEC system IS a fly-by-wire system. There are no cables between the throttles and the fuel metering component.