The mass air flow (MAF) sensor is an air flow meter that measures the amount of air entering the engine. The powertrain control module (PCM) uses the MAF sensor signal in order to provide the 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 the sensor on the signal circuit. The sensor uses the voltage in order to produce a frequency based on inlet air flow through the sensor bore. The PCM uses the barometric pressure, air density, manifold pressure, throttle position, and the engine RPM in order to calculate a predicted MAF value. The PCM compares the actual MAF sensor signal to the predicted MAF value in order to determine if the signal is stuck based on a lack of variation, or is too low or too high for a given operating condition. DTC P0101 will set if the actual MAF sensor signal is not within a predetermined range of the calculated MAF value.
Possible causes for this code are:
- Faulty sensor
- Broken wires at the sensor connector. Tug on each to see if it stretches or breaks
- Loose air intake duct or breather hose / tube between the MAF sensor and the engine
- Dirty sensor. Try spraying cleaner inside the sensor, then take for drive to "Blow out" the cleaner
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