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 :
Find out what kind of system you have and verify that voltage to the fuel level sensor is present at the fuel pump wiring harness. 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 C3399 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 C3399.
Fortunately, C3399 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.