Engine Operating Modes Are Being Discussed

Multiple Choice

Engine operating modes are being discussed. Technician A says that when the engine is in closed-loop mode, the PCM monitors sensor inputs, then adjusts the timing, air fuel ratio, and emission controls. Technician B says the system will switch into open loop when the throttle is fully opened or the oxygen sensors cool down during idle. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B