Individual Cylinder Fuel Trim (-2009)

General 

The Engine control module (ECM) controls the fuel according to the description in Fuel trim above, but has another refined system for improving exhaust values, namely individual cylinder fuel trim.

In short, this means that the Engine control module (ECM) can detect the fuel/air mixture composition for each individual (6 cylinders).

To achieve this requires, among others, refined heated oxygen sensors that are very sensitive to the oxygen content in the exhausts.

Should problems occur, which would mean that the sensors, "lose" their extra sensitivity, the Engine control module (ECM) will return to traditional fuel trim.

This will not force the vehicle outside any limit values for exhausts, since this is more than enough to give "clean" exhausts.