P0198 Engine Oil Temperature Sensor High Input - Automotive Repair Guides & Equipment

COMPONENT LOCATION

GENERAL DESCRIPTION

The CVVT uses the engine oil to change the cam timing and its density changes according to the engine temperature. The Oil Temperature Sensor (OTS) signal is used by the ECM to compensation for the temperature differences. The Oil Temperature Sensor measures the engine oil temperature before the engine oil flows into the Oil-flow Control Valve (OCV). According to the measured temperature, the Engine Control Module (ECM) 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., ECM sets P0198.

DTC DETECTING CONDITION

Item

Detecting Condition

Possible Cause

DTC Strategy

Signal High

1.	Poor connection

2.	Open or short to battery in signal harness

3.	Open in ground harness

4.	Faulty OTS

ECM

Enable
Conditions

Case 1

Engine running state > 60 sec

Coolant temperature < 110 °C(230°F)

Case 2

Engine running state > 90 sec

Threshold 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

3 Driving Cycles

SPECIFICATION

Temperature(°C/°F)	Resistance(kΩ)
-40°C	52.15kΩ
-20°C	16.52kΩ
0°C	6.0kΩ
20°C	2.45kΩ
40°C	1.11kΩ
60°C	0.54kΩ
80°C	0.29kΩ

DIAGNOSTIC CIRCUIT DIAGRAM

SIGNAL WAVEFORM & DATA

Fig.1) Normal data of IATS & ECTS & EOTS at ig on

Fig.2) Normal data of IATS & ECTS & EOTS after warming up.

Fig.3) Normal waveform of EOTS at 76°C (168.4°F)

MONITOR GDS DATA

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

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.

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 ECM’s connector or was repaired and ECM memory was not cleared. Thoroughly check connectors for looseness, poor connection, ending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary

TERMINAL AND CONNECTOR INSPECTION

1.	Many malfunctions in the electrical system are caused by poor harness and terminals. 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 as necessary and go to “Verification of Vehicle Repair” procedure .
	▶ Go to ” Signal Circuit Inspection ” procedure.

SIGNAL CIRCUIT INSPECTION

■ Check voltage

1.	IG “OFF” and disconnect OTS connector.

IG “ON”

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

Approx. 3.3V

Is the measured voltage within specification ?

	▶ Go to “Ground Circuit Inspection” procedure.
	▶ Go to “Check open in harness” as follow.

■ Check open in harness

1.	IG “OFF” and disconnect OTS connector and ECM connector.

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

Below 1Ω

Is the measured resistance within specification ?

	▶ Go to “Ground Circuit Inspection” procedure.
	▶ Repair open in harness and go to “Verification of Vehicle Repair” procedure.

GROUND CIRCUIT INSPECTION

■ Check open in harness

1.	IG “OFF” and disconnect OTS connector and then IG “ON”.

2.	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”)

Voltage difference between measurement “A” and “B” is below 200mV.

Is the measured voltage within specification ?

	▶ Go to “Component Inspection” procedure.
	▶ Repair contact resistance or open in harness

COMPONENT INSPECTION

■ Check OTS resistance

1.	IG “OFF” and disconnect OTS connector.

Measure resistance between signal and ground terminals of OTS connector after checking out the temperature of EOTS with GDS (Component Side)

Specification :

Temperature(°C/°F)	Resistance(kΩ)
-40°C	52.15kΩ
-20°C	16.52kΩ
0°C	6.0kΩ
20°C	2.45kΩ
40°C	1.11kΩ
60°C	0.54kΩ
80°C	0.29kΩ

Is the measured resistance within specification ?

▶ Substitute with a known – good ECM and check for proper operation. If the problem is corrected, replace ECM and go to “Verification of Vehicle Repair” procedure.

There is a memory reset function on GDS that can erase optional parts automatically detected and memorized by ECM. Before or after testing ECM on the vehicle, use this function to reuse the ECM on the others

▶ Substitute with a known – good OTS and check for proper operation. If the problem is corrected, replace OTS

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