Err 16?

Hi here is my setup:
apm2.6 by 3DR + 6m-neo/mag from holy-bros running AC3.2 rc-4
4108-380kv @4s 1555 prop

need help figuring out:

what is ERR16 error
are motor values being used for yaw correction

log files attached.

Thank you,

ERR 16 is the EKF check… odd because APM2 doesn’t run the EKF.

Edit: apparently we check the inertial nav errors if the EKF isn’t available. Can be compass or vibration issues.

Are you having trouble with yaw? I don’t understand the question.