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 compensation 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 (ECM) compensates the oil-flow control valve operation time.
Checking output signals from oil temperture sensor every 15 sec. under detecting condition, if an signal is low for more than 12.5 sec., ECM sets P0197.
Item
Detecting Condition
Possible Cause
DTC Strategy
Signal low
Poor connection
Short to ground in harness
Oil temp.sensor
ECM
Enable
Conditions
Case 1
Engine running state > 60 sec
Coolant temperature < 110 ?(230?)
Case 2
Engine running state > 90 sec
Threshold value
Oil temperature sensor's signal < 0.1V
Diagnosis Time
Continuous (More than 12.5 sec.failure for every 15 sec.test)
MIL On Condition
3 Driving Cycles
Temperature(?/?)
Resistance(k?)
-40?
52.15?
-20?
16.52?
0?
6.0?
20?
2.45?
40?
1.11?
60?
0.54?
80?
0.29?
Fig.1) Normal waveform of EOTS at 76? (168.4?)
Fig.2) Normal data of IATS & ECTS & EOTS at ig on
Fig.3) Normal data of IATS & ECTS & EOTS) after warming up.