For 1990-2009 cars

Voltage Tech 2 (V) | R Nominal (k ohms) | Outside Air Temp (°F) | Outside Air Temp (°C)
--- | --- | --- | ---
4.72-4.74 | 171.6 | -22 | -30
4.52-4.54 | 94.63 | -4 | -20
4.22-4.25 | 54.21 | 14 | -10
3.81-3.85 | 32.00 | 32 | 0
3.31-3.34 | 19.61 | 50 | 10
2.76-2.79 | 12.31 | 68 | 20
2.22-2.25 | 7.959 | 86 | 30
1.73-1.75 | 5.268 | 104 | 40
1.31-1.34 | 3.563 | 122 | 50
0.99-1.01 | 2.458 | 140 | 60
The Tech 2 will display sensor value as a voltage. This gives the approximate voltage expected at different ambient temperatures as well as what should be read with an ohmmeter connected to the sensor. Since this is raw data any heat from underhood that changes ambient temp around the sensor might skew the reading, so let the engine compartment cool.