All of the Following Statements Are True EXCEPT

Multiple Choice

All of the following statements are true EXCEPT:

A) the fuel system monitor operates continuously when the fuel system is in closed loop.
B) the heated oxygen sensor monitor (HO₂S) changes the injector pulse width while it checks the upstream O₂ sensor to see that its oscillating frequency is fast enough.
C) O₂ sensors are monitored even before closed loop.
D) a pre-catalyst sensor is called S₀ and a post-cat sensor is called sensor 1 (S₁) .