P0197, P0198 EOT Sensor: Description

WARNING: This page is about a different car, the 2009 Nissan Maxima. However, it is still accessible from the selected car via links, so may be relevant.

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.

Fig 1: Identifying Sensor And Terminal

Courtesy of NISSAN MOTOR CO., U.S.A.

VOLTAGE SPECIFICATION

Engine oil temperature [°C (°F)]

Voltage⁽¹⁾ (V)

Resistance (kΩ)

-10 (14)

4.4

7.0 - 11.4

20 (68)

3.5

2.1 - 2.9

50 (122)

2.2

0.68 - 1.00

90 (194)

0.9

0.236 - 0.260

110 (230)

0.6

0.143 - 0.153

⁽¹⁾	These data are reference values and are measured between ECM terminals 54 (Engine oil temperature sensor) and 52 (Sensor ground).

Fig 2: Resistance And Temperature Graph

Courtesy of NISSAN MOTOR CO., U.S.A.