Cable Failure
It is the breaking of the link between the actuator and the throttle lever when the inner wire separates as a result of fatigue or friction. Once the link is broken, the throttle lever is determined only by the engine's own return spring; with a sound spring the lever drops to idle. For that reason a cable failure does not stop the engine, it only removes speed control.
Failure is mostly not sudden. In a stranded wire, individual strands break first, the cable frays at that point and friction increases. Looking for this fraying at the ends and in sharp bend areas during periodic checks is the most practical way of catching a failure in advance.
From a safety point of view two separate questions must not be confused. Whether the engine drops to idle when the cable breaks depends on the soundness of the return spring and on the throttle lever being able to move freely. If the lever joint is seized the lever may stay where it is; that means the engine keeps running at that speed.
For this reason emergency shutdown is never based on the throttle actuator. The GS740 and GS740-3P are not a governor and declare no engine shutdown function; shutdown must be built through the engine's own fuel shut-off solenoid or fuel/air cut-off chain. The kit only drives the position of the throttle lever.
Context in which this term is used: Electronic speed and throttle control on a diesel engine