Mini APM v.1 yaw stabilization

I am setting up a Mini APM v3.1 with 3.4 firmware in a plane. When in ‘Stabilize’ ‘FBW-A’ ‘Loiter’ modes whether armed or not, I see that the pitch and roll axes are being stabilized when rolling and pitching the plane. However, there is no rudder movement when yawing the plane. I haven’t been able to find how to address this in the parameters.
Could someone please advise?
Thank you.