DTC P0101: Mass Airflow Sensor System Performance: Description

Mass Airflow (MAF) sensor is an airflow meter that measures the amount of air entering engine. Powertrain Control Module (PCM) uses MAF sensor signal to provide correct fuel delivery for a wide range of engine speeds and loads. A small quantity of air entering the engine indicates deceleration or idle. A large quantity of air entering the engine indicates an acceleration or high load situation. The MAF sensor has an ignition 1 voltage circuit, a ground circuit and a signal circuit. The PCM applies a voltage to MAF sensor on the signal circuit. MAF sensor uses the voltage to produce a frequency based on inlet airflow through the sensor bore. The PCM uses barometric pressure, air density, manifold pressure, throttle position, and engine RPM to calculate a predicted MAF sensor value. The PCM compares actual MAF sensor signal to the predicted MAF value to determine if signal is stuck based on a lack of variation, or is too low, or too high for a given operating condition. Diagnostic Trouble Code (DTC) will set if actual MAF sensor signal is not within a predetermined range of calculated MAF value.