It is considered generic because it applies to all makes and models of vehicles, although specific repair steps may be different depending on your car model.
Possible Causes :
With the valve disconnected, the red voltmeter lead should be attached to the IMRC valve power wire and the black voltmeter lead connected to ground. If all testing has passed so far yet you still have the same code, check your scan tool and see if it can open and close the IMRC valve.
Diagnostic trouble code C0256 is not difficult to diagnose and repair. Thus, it always pays to have a qualified technician to look after your vehicle should this error code arise.
Diagnosing this code requires the engine to be in good running shape, without unmetered air entering the engine. If other codes that relates to misfiring condition, lean running or air entering the engine is present, then you must first fix those error codes before C0256.
Fortunately, C0256 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.