ROVER - Metal Frame

I am using a Pixhawk FC for my rover - The rover has GPS and has been calibrated prior to installation in the vehicle. Because my vehicle is mostly metal the Pixhawk is mounted on carbon fiber sheet. When I try to arm I get “PreArm - Check Mag Field” The vehicle has failed a pre-arm check. In order to arm the vehicle, resolve the failure.

Having an all metal vehicle - What is recommended to turn off for use of this rover?