DTC P0101: Mass Air Flow Sensor Performance: Description

WARNING: This page is about a different car, the 2002 GMC Savana Special, 2002 GMC Savana Camper Special, 2002 GMC Savana, and 2002 Chevrolet Chevy Express. However, it is still accessible from the selected car via links, so may be relevant.

The Mass Air Flow (MAF) sensor is an air flow meter. The MAF sensor is supplied ignition voltage and a ground. The MAF sensor heats a wire grid or a small wire within the sensor to a predetermined temperature. As inlet air flows across and cools the wire grid, the MAF sensor must increase current flow to the wire grid in order to maintain a constant wire grid temperature. The MAF sensor converts the required wire grid current flow into a frequency signal. The Powertrain Control Module (PCM) and the Alternative Fuels ECM monitor the MAF signal circuit frequency and determine the flow and mass of the air entering the engine.

The PCM and the Alternative Fuels ECM convert the MAF signal circuit frequency into a grams per second value. During low air flow rates, such as at engine idle, the MAF sensor will produce a low frequency signal, around 2000 Hz or 6 grams per second. During high air flow rates, such as at wide open throttle-road load, the MAF sensor will produce a high frequency signal, around 9000 Hz or 125 grams per second.

The PCM and the Alternative Fuels ECM monitor the actual MAF sensor air flow rate and compare the actual air flow rate to a calculated air flow rate. The calculated air flow rate is based upon engine speed and Barometric (BARO) pressure. The PCM and the Alternative Fuels ECM use the MAP sensor in order to determine the BARO when the ignition switch is turned ON and the engine is NOT cranked. This BARO reading may also be updated whenever the engine is operated at wide open throttle.

This DTC is used to indicate that the actual MAF sensor air flow rate does not match a calculated air flow rate.