Circuit Description

Mass Airflow (MAF) sensor measures airflow rate into engine. MAF sensor has a switched battery feed, signal circuit, signal return circuit and a ground. As airflow increases, a greater amount of current is required to maintain the hot wires at a constant temperature. MAF sensor converts the changes in current draw to a frequency signal read by the ECM. ECM calculates airflow (grams per second) based on this signal.

ECM monitors the MAF sensor frequency and can determine if sensor is stuck low, stuck high, not providing the airflow value expected for a given operating condition, or not providing the signal variation expected during normal operation. If MAF sensor frequency varies less than a predetermined minimum amount, this DTC will set.