DTC Description: Notes

WARNING: This page is about a different car, the 2018 Nissan Titan XD. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: If DTC P0102 is displayed with other DTC, first perform the trouble diagnosis for other DTC.

The Mass Air Flow sensor is a frequency based device. A constant voltage is applied to a heated wire. The wire is positioned in the air stream and is heated by the electrical current that the voltage produces. As air flows across it, it cools down. The heated wire or film is a positive temperature coefficient (PTC) resistor. This means that the resistance drops when the temperature drops. The drop in resistance allows more current to flow through it in order to maintain the programmed temperature. This current is changed to a frequency which is sent to the ECM and interpreted as air flow. Adjustments to air temperature and humidity are taken into consideration since they also affect the temperature of the heated wire or film. The Mass Air Flow sensor receives a 12 volt power supply from the ECM.