Why does knock sensor keep vehicle from starting

When the knock sensor senses a tap,it shuts motor down to keep damage from engine.

Only when it's been drvning around and is warm when it cools it starts rte up

The sensor gets hot and retards the timing hense the no start out of time

Yes, Joe in a way it does, show when timing is off all so,it is about like a cam or crank sensor,it is a pulse signal,which goe,s to the ECM,and control firing and fuel in turn shutting it down if there is a issue with any of these.

Knock sensor will not prevent it from starting.

What about the 02circuit no activity detected bank 1 sensor 1

What about the ignition relay

yes, the knock sensor will affect starting , like any other sensor, the ECU "looks" at all ports, should a broken wire on the knock sensor, the ECU will start erractically( some Cars),maybe cause "back-firing" hard satarting, etc(so does other sensors too) however, its purpose - mainly - is to control timing at driving speeds, Most failures are directly due to bad wiring, coupling connectors, etc, seldom found a senosr faulty (Opel)

what color is the wire for a knock sensor on a 05 buick rodevous with a 3.4?