Air Mass Control, Basic Function: Diagnosis
In principle, the air mass/combustion is the same as engine torque. Air mass control is therefore of great interest when diagnosing bad performance.
There is a special menu in the diagnostic tool from which values of interest can be read. The most important is the deviation between requested and current air mass/combustion.
The current value must always follow the requested value, occasionally after a short delay. If this does not take place, there may be a fault in the turbocharger.
NOTE:
A fault in the throttle control can be eliminated because deviations between the present throttle position value and its desired value place the throttle control in limp-home.