Injector Classification: Notes
The classification of injectors into 3 classes describes the quantity characteristic of the injector. This will make it possible in the future to match the engine software to the tolerances of the injector within a more narrowly graduated range. Classification can be clearly recognized, and assigned only by means of a scan tool.
Classified injectors can be recognized by the part number and identification on the magnetic head (circle with a number between 1 and 3 inside) . The number corresponds to the classification stage.
These general conditions equally apply if, as a result of replacing an engine, carrying out repairs to the cylinder head etc., the cylinder selective assignment of the injectors or the engine control module assignment may have changed. If proper attention is not paid to the classification on these vehicles driveability and smoking concerns could result.
If an injector is replaced, it is then necessary to assign the classification number to the corresponding cylinder with the scan tool in the control module.