US Patent 7600495 Method for controlling an engine having variable cam timing

A method for operating an engine having a variable cam timing control system, for controlling a camshaft angle in such engine. The method includes deactivating the variable cam timing system and setting the camshaft angle to a predetermined angle for a predetermined duration after failure in a sensor used to control the variable cam timing system and then reactivating the variable cam timing system after such predetermined time. The deactivating continues during the predetermined duration in the presence of a subsequent failure of the sensor during the predetermined duration. The reactivating comprises driving the cam angle to a camshaft angle established by the variable cam timing system in a predetermined manner. The reactivating occurs over a predetermined reactivation time.