If it is the old black guardpack you can put a resistor between common and the sensor 1, 2, or 3 that is bad. I believe that you can use a 1/2 watt 75 ohm resistor for either of the bad thermistors. If you do this at least you still have the oil protection and the two other thermistors in place to keep the unit operating safely.

As far as the bypassing I have seen bulletins from trane on the larger compressors saying that it is ok to bypass all three sensors.