Air Flow Adaptation (Turbo Only)

Fig 1: Identifying Air Flow Adaptation

Courtesy of VOLVO CARS OF NORTH AMERICA.

NOTE:

This information regards the air flow adaptation over the throttle unit, not to be confused with the control module's fuel adaptation (lambda adaptation).

There is a correction factor in the Engine control module (ECM) for adjusting the leakage flow over the throttle unit. Leakage flow means the air that does not go through the throttle unit, but goes via the crankcase ventilation, power brake booster and EVAP system. For the control module to be able to learn the adjustments needed in the different air flow areas, there are two adaptation areas. One for idling and one for part load. These values are saved when the engine is switched off.

These values can be read off using the "Air mass, correction value" and "Leakage flow over throttle unit" parameters.