Assuming you've checked the oil with the dipstick, and it's ok, then the sender is probably faulty. Common fault.
As for the brake pads, again assuming the both the inner and the outer pads on both sides have plenty of meat on them, then it could be the connectors. It's also not unknown for the wire embedded in the pad to be too far "into" the material, so that it ends up showing pad wear when, in reality, there is still plenty of life left on them.
I had this happen - my garages solution (unbelievably!) was to bridge the wires in the loom with a fecking scotchlock!