In CVVT system, the working fluid is engine oil. But its density varies according to temperature, PCM performs oil quantity correction based on the signal from engine oil temperature sensor over the various range of temperature. Main function of Oil Pressure Sensor is as follows.
intake air valve control solenoid(oil control valve) duty correction : As coil resistance varies according to oil temperature, excessive current flows at low temperture and low current at high temperature without duty correction. Therefore, PCM performs duty correction properly according to output signal from oil temperature sensor to supply constant current which is free from the change of oil temperature.
CVVT system operation starting temperature determination : As CVVT response gets weaker due to the friction of engine components such as valve at low temperature, PCM operates CVVT at above specific temperture based on output signal from oil temperture sensor.
improved CVVT controllability : CVVT response speed varies as oil temperature, PCM improves controllability throughout estimating response speed with oil temperture sensor output signal.
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.
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 state >60 sec ● Coolant temperature < 110 °C(230°F) |
Case 2 | ● Engine running state >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 |
Temperature(°C/°F) | Resistance(kΩ) |
-20°C/ -4°F | 16.52kΩ |
20°C/ 68°F | 2.45kΩ |
80°C/ 176°F | 0.29kΩ |
