code p1383 cylinder position sensor intermittent interruption. what do I check?

The first step is check the engine oil quality, type and grade that is being used and how often is the service made, 2nd inspect the variable cam solenoids physically and make a electrical test to check if the solenoids work or not (some solenoids work with a digital voltage and can not be tested with the regular procedure), the last step is check the cams gears, some times happen they broke inside and can not control the position of the cams no more