Possible causes

– Engine not at operating temperature.
– Cooling system problem of stuck thermostat.
– Faulty Engine Oil Temperature (EOT) sensor
– Engine Oil Temperature (EOT) sensor harness is open or shorted
– Engine Oil Temperature (EOT) sensor circuit poor electrical connection
– Faulty Engine Control Module (ECM).

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)

P1184 Description

The Engine Oil Temperature (EOT) sensor is a thermistor device in which resistance changes with temperature. The electrical resistance of a thermistor decreases as the temperature increases and the resistance increases as the temperature decreases. The varying resistance affects the voltage drop across the sensor terminals and provides electrical signal to the Engine Control Module (ECM) corresponding to temperature.

Thermistor-type sensors are considered passive sensor. A passive sensor is connected to a voltage divider network so that varying the resistance of the passive sensor causes a variation in total current flow.

Voltage that is dropped across a fixed resistor in a series with the sensor resistor determines the voltage signal at the ECM. This voltage signal is equal to the reference voltage minus the voltage drop across the fixed resistor.

The EOT sensor measures the temperature of the engine oil. The sensor is typically threaded into the engine oil lubrication system. The ECM can use the EOT sensor input to determine the following:

– On variable cam timing (VCT) applications the EOT input is used to adjust the VCT control gains and logic for camshaft timing.
– The ECM can use the EOT sensor input in conjunction with other ECM inputs to determine oil degradation
– The ECM can use EOT sensor input to initiate a soft engine shutdown. To prevent engine damage from occurring as a result of high oil temperature, the ECM has the ability to initiate a soft engine shutdown. Whenever engine RPM exceeds a calibrated level for a certain period of time, the ECM will begin reducing power by disabling engine cylinders.

P1184 Information for specific makes

P1184 FORD
P1184 HYUNDAI