Simply changing the parameter isn't enough. You must call the AICC mode in your program.

Yes, but caution is required. On a lathe, 8901=2 improves threading consistency and eliminates "chatter" on long taper turns. However, for part-off operations or grooving, use G61 to disable it. Do not use 8901=2 on a Swiss-type lathe with independent guide bushings.

Fanuc parameter is a maintenance setting used to control the detection of fan motor errors. It is most commonly modified to bypass the ALM701 (Fan Motor Overheat) alarm, which occurs when a control unit fan fails or runs too slowly. Understanding Parameter 8901#0