You can test the thing yourself with a good ohmmeter.
All degrees listed in F.
Temp. Reading
0 25000 ohms
20 13,500 ohms
40 7,500 ohms
70 3,400 ohms
100 1,800 ohms
160 450 ohms
210 185 ohms
That would be read with the connector off and the meter between the two leads.
Problems with the circuit include open or shorted wiring, and a shifted sensor.
Odd ouputs way out of range will set a code 15 I believe.