20 deg is "cold". 80 deg is "hot".
According to my manual, specifications for the engine temp sensor is in ohms, with resistance across the 2 pins as:
"cold" = 2.5Kohm
"hot" = 0.3Kohm.
The relationship is not linear, so 10deg might be around 5Kohm. But I would suspect that as long as you have similar order of magnitude readings, you could assume the sensor is working correctly.
Also, if there is a problem, Code 31 might be present when you do the ECU diagnosis.