Monitor Description

The MAF (Mass Air Flow) meter is a sensor that helps the ECM calculate the amount of air flowing through the throttle valve. The ECM uses this information to determine the fuel injection time and provide a proper air-fuel ratio. Inside the MAF meter, there is a heated platinum wire exposed to the flow of intake air. By applying a specific current to the wire, the ECM heats this wire to a given 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 air flow through the sensor and the ECM interprets this voltage as the intake air amount. If there is a defect in the sensor or an open or short circuit, the voltage level will deviate from the normal operating range. The ECM interprets this deviation as a defect in the MAF meter and sets a DTC.

Example:

If the MAF meter voltage is higher than 2.2 V when the engine is idling, the ECM sets P0101 (2 trip detection logic). If the MAF meter voltage is higher than 0.7 V when the throttle valve is opened, the ECM sets P0101 (2 trip detection logic).