MAF stands for Mass Air Flow.
The MAF sensor measures the amount of air entering the engine and provides that information to the
ECU.
This measurement can be particularly important on diesel engines because airflow calculations are
closely related to EGR and fueling strategies.
For example, if the ECU expects a certain amount of air but receives an unexpected MAF reading, it may
identify a problem.
Diesel
MAF-related calibration work is common on diesel ECUs.
Petrol
MAF sensors are also used on many petrol engines.
However, some modern petrol engines rely on different load calculation strategies involving MAP,
throttle position and other sensors.