Monitor Description

The ECM calculates the volume of air flowing through the throttle valve using signals it receives from the Mass Air Flow (MAF) meter. The ECM uses this information to determine the fuel injection time and provide an appropriate air-fuel ratio. Inside the MAF meter, there is a heated platinum wire which is exposed to the flow of intake air. By applying a specific current to the wire, the ECM heats it to a certain temperature. The flow of incoming air cools the wire and an internal thermistor, changing their resistance. To maintain a constant current value, the ECM varies the voltage applied to these components in the MAF meter. The voltage level is proportional to the airflow through the sensor and the ECM uses the voltage to calculate the intake air volume. If there is a defect in the sensor, the voltage level deviates from the normal operating range. The ECM interprets this as a malfunction in the MAF meter and sets the DTC.

Example:

If the voltage is outside the normal range, the ECM determines that there is a malfunction in the MAF meter and sets the DTC.