The engine oil temperature sensor is used to detect the engine oil temperature. The sensor modifies a voltage signal from the ECM. The modified signal returns to the ECM as the engine oil temperature input. The sensor uses a thermistor which is sensitive to the change in temperature. The electrical resistance of the thermistor decreases as temperature increases.
<Reference data>

Engine oil temperature [°C (°F)] | Voltage*　(V) | Resistance　(kΩ)
–10 (14) | 4.4 | 7.0 - 11.4
20 (68) | 3.5 | 2.1 - 2.5
50 (122) | 2.2 | 0.68 - 1.00
90 (194) | 0.9 | 0.236 - 0.260
110 (230) | 0.6 | 0.143 - 0.153
*: These data are reference values and are measured between ECM terminals 27 (Engine oil temperature sensor) and 26 (Sensor ground).