code P021

P0021 NISSAN - Intake Valve Timing Control Performance Bank...Possible causes; Faulty Intake Valve Timing Control Solenoid, Valve Intake Valve Timing Control Solenoid Valve harness is open or shorted, Intake Valve Timing Control Solenoid Valve circuit poor electrical connection, Faulty Camshaft Position Sensor, Camshaft Position Sensor harness is open or shorted, Camshaft Position Sensor circuit poor electrical connection, Faulty Crankshaft Position Sensor (POS)...Since the Intake valve timing control solenoid valve uses oil flow to control timing, dirty oil can cause the valve to stuck open or close. Before replacing the valve, change engine oil and filter and reset engine code......The intake valve timing control solenoid valve changes the oil amount and direction of flow through intake valve timing control unit or stops oil flow. The longer pulse width advances valve angle. The shorter pulse width retards valve angle. When ON and OFF pulse widths become equal, the solenoid valve stops oil pressure flow to fix the intake valve angle at the control position.