Fuel System > Engine Control System > P0198 Engine Oil Temperature Sensor High Input

Component Location

General Description

The fluid of the CVVT is the engine oil and its density changes according to the engine oil temperature. At this time the Oil Temperature Sensor (OTS) helps compensate against the temperature differences. The Oil Temperature Sensor measures the engine oil temperature before the engine oil comes into the Oil-flow Control Valve (OCV).

According to the measured temperature, the Engine Control Module (PCM) compensates the oil-flow control valve operation time.

DTC Description

Checking output signals from oil temperture sensor every 15 sec. under detecting condition, if an signal is high for more than 12.5 sec., PCM sets P0198. MIL(Malfunction Indication Lamp) turns on when the malfunction lasts till consecutive 2 driving cycle.

DTC Detecting Condition

Item

Detecting Condition

Possible cause

DTC Strategy

•	Signal low

•	Poor connection

•	Open or short to battery in signal harness

•	Open in ground harness

•	Oil temp.sensor

•

PCM

Enable Conditions

Case 1

•	Engine running >60 sec

•	Coolant temperature < 110 °C(230°F)

Case 2

•	Engine running >90 sec.

Thresh old value

•	Oil temperature sensor's signal >4.9V

Diagnosis Time

•	Continuous (More than 12.5 sec.failure for every 15 sec.test)

MIL On Condition

•	2 Driving Cycles

Specification

Temperature(°C/°F)	Resistance(kΩ)
-20°C/ -4°F	16.52kΩ
20°C/ 68°F	2.45kΩ
80°C/ 176°F	0.29kΩ

Schematic Diagram

Monitor DTC Status

Check DTC Status

(1)	Connect scantool to Data Link Connector(DLC).

(2)

IG "ON".

(3)	Select "DTC" button, and then Press "DTC Status" to check DTC's information from the DTCs menu.

(4)	Read "DTC Status" parameter.

(5)

Is parameter displayed "Present fault"?

	▶ Go to "Terminal and connector inspection" procedure.
	▶ Fault is intermittent caused by poor contact in the sensor's and/or PCM's connector or was repaired and PCM memory was not cleared. Thoroughly check connectors for looseness, poor connection, ending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure.

Terminal And Connector Inspection

1.	Many malfunctions in the electrical system are caused by poor harness and terminal condition. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.

2.	Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.

Has a problem been found?

	▶ Repair or replace if necessary and go to "Verification of Vehicle Repair" procedure
	▶ Go to "Signal Circuit Inspection" procedure.

Signal Circuit Inspection

■ Check Voltage

1.	IG "OFF" & ENG "OFF".

2.	Disconnect OTS connector.

3.	IG "ON" & ENG "OFF".

Measure voltage between signal terminal of OTS harness connector and chassis ground.

Specification : Approx. 5V

Is the measured voltage within specification ?

	▶ Go to "Ground Circuit Inspection" procedure.
	▶ Go to "Check open in harness" as follows.

■ Check Open In Harness

1.	IG "OFF" & ENG "OFF"

2.	Disconnect OTS and PCM connector.

Measure resistance between signal terminal of OTS harness connector and OTS signal terminal of PCM harness connector.

Specification : Approx. below 1Ω

Is the measured resistance within specification ?

	▶ Go to "Ground Circuit Inspection" procedure.
	▶ Repair or replace open in harness, and then go to "Verification of Vehicle Repair" procedure.

Ground Circuit Inspection

■ Check Open In Harness

1.	IG "OFF" & ENG "OFF"

2.	Disconnect OTS connector and IG "ON"

3.	Measure voltage between signal terminal of OTS harness connector and chassis ground.(Measurement "A")

Measure voltage between signal and ground terminals of OTS harness connector.(Measurement "B")

Specification : Measurement "A" - Measurement 'B' = Approx. below 200mV

Is the measured voltage within specification ?

	▶ Go to "Component Inspection" procedure.
	▶ Repair or replace contact resistance or open in harness and then, go to "Verification of Vehicle Repair" procedure.

Component Inspection

■ Check OTS Resistance

1.	IG "ON" & ENG "OFF"

2.	Monitor Oil Temperature parameter on the scantool

3.	IG "OFF" & ENG "OFF"

4.	Disconnect OTS connector.

Measure resistance between signal and ground terminals of OTS connector after checking out the oil temperature with scantool.

Specification :

Temperature(°C/°F)	Resistance(kΩ)
-20°C/ -4°F	16.52kΩ
20°C/ 68°F	2.45kΩ
80°C/ 176°F	0.29kΩ

Is the measured resistance within specification ?

	▶ Substitute with a known - good PCM and check for proper operation. If the problem is corrected, replace PCM and go to "Verification of Vehicle Repair" procedure.
	▶ Substitute with a known - good OTS and check for proper operation. If the problem is corrected, replace OTS and go to "Verification of Vehicle Repair" procedure.

Verification Of Vehicle Repair

After a repair, it is essential to verify that the fault has been corrected.

1.	Connect scantool and select "DTC" button.

2.	Press "DTC Status" button and confirm that "DTC Readiness Flag" indicates "Completed". If not, drive the vehicle within conditions noted in the freeze frame data or enable conditions

3.	Read "DTC Status" parameter

Is parameter displayed "History(Not Present) fault"?

	▶ System performing to specification at this time. Clear the DTC
	▶ Go to the applicable troubleshooting procedure.