When the tractor is trying to acquire the guidance line, any time it steers the tractor to the steering stops, the system kicks out.  Is it normal for a tractor that's been calibrated to steer all the way to the steering stops?

Once the manual override setting is high enough to keep the steering system from kicking out when acquiring the guidance line, I cannot disengage the steering system by turning the steering wheel. 

I have calibrated the pressure transducer many times.  The manual override setting calculated by the system is way to low.

The steering wheel does turn a little bit (almost unnoticeable) when the steering system is engaged.

Any thoughts on what might be causing the issue?