Mass Airflow Sensor

WARNING: This page is about a different car, the 2003 Pontiac Grand Prix, 2003 Chevrolet Malibu, and 2003 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.

The Mass Airflow (MAF) sensor, located in left front of the engine, in the air cleaner duct, is an air flow meter that measures the amount of air entering the engine. See Figure . The Powertrain Control Module (PCM) uses the MAF sensor frequency signal to provide the correct fuel delivery for a wide range of engine speeds and loads. A small quantity of air entering the engine indicates a deceleration or idle. A large quantity of air entering the engine indicates an acceleration or high load condition. The MAF sensor has the following:

An ignition 1 voltage circuit.
A ground circuit.
A signal circuit.

The PCM applies a voltage to the sensor on the signal circuit. The sensor uses the voltage to produce a frequency based on inlet air flow through the sensor bore. The frequency varies within a range of around 2000 Hertz at idle to about 10,000 Hertz at maximum engine load. DTC sets if the PCM detects a frequency signal higher or lower than the possible range of a properly operating sensor.