The MAF sensor uses a hot wire sensing element to measure the air flow rate entering the engine. The hot wire is maintained at a constant temperature. The temperature of the hot wire changes with varying air flow. The current required to keep the constant temperature is measured and converted to a voltage which is converted by the PCM to an air flow value.
PCM uses the MAF sensor to measure the air flow into the engine. MAF sensor used for EGR, fuel system, and regeneration.
IDS: MAF_A (flow) and MAF_HZ (frequency)