US Patent 7357019 Faulty lifter oil manifold assembly solenoid diagnostic system

A diagnostic system that detects a faulty lifter oil manifold assembly solenoid includes a current measurement module, a time delay module, a voltage measurement module, and a diagnostic module. The current measurement module measures current flowing through the solenoid when a trigger signal is enabled. The time delay module determines a time delay based on the measured current. The voltage measurement module measures a supply voltage that powers the solenoid. The diagnostic module determines whether the solenoid is faulty based on the time delay and supply voltage.