DTC P0197, P0198: EOT Sensor: Description

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 EOT Sensor, Gasket And Terminal

Courtesy of NISSAN NORTH AMERICA, INC.

VOLTAGE AND RESISTANCE REFERENCE DATA

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 39 (Engine oil temperature sensor) and 34 (Sensor ground).

Fig 2: Engine Oil Temperature Sensor Resistance Versus Temperature Graph

Courtesy of NISSAN NORTH AMERICA, INC.