The CVVT (Continuously Variable Valve Timing) system is installed to the chain sprocket of the intake camshaft. This system controls the intake camshaft to provide the optimal valve timing for every driving condition. The PCM controls the Oil Control Valve(OCV), based on the signals output from mass air flow, throttle position and engine coolant temperature. The CVVT controller regulates the intake camshaft angle using oil pressure through the OCV. As result, the relative position between the camshaft and the crankshaft becomes optimal, and the engine torque improves, fuel economy improves, exhaust emissions decrease under overall driving conditions.
PCM monitors OCV stuck while cam sinal is normally generating and Valve cleaning is not in progress .
If the CAM Acutal Position is too high or low and Difference between Cam Actual Position and Desire Position is higher than 20° PCM determines that a fault exists and a DTC is stored.
Item
Detecting Condition
Possible cause
DTC Strategy
? Determines if oil control valve is stuck
? Oil Pressure Loss
? OCV seizure
Enable Conditions
? Valve cleaning not in progress
? CAM signal is normally generating
Threshold value
Case 1
? Cam Actual Position > 50 CAD or Difference between CAM Actual Position and Desire Position > 20 CAD
Case 2
? Cam Actual Position < 5 CAD or Difference between CAM Actual Position and Desire Position > 20 CAD
Diagnosis Time
? Continuous (Within 1min.)
MIL On Condition
? 2 driving Cycle
Resistance (?)
6.7 ~ 7.7
Fig.1. Idle - normal Condition
Fig.2. Acceleration