SENSOR-MASS AIR FLOW (MAF)
DESCRIPTION
The Mass Air Flow (MAF) Sensor is located in the air intake port between the air filter and the turbocharger. The MAF sensor uses semiconductor technology throughout, and is used to calculate the air mass flowing past it per time unit. This mass is important for determining the exhaust gas recirculation rate. The MAF sensor sends a corresponding signal to the ECM, which evaluates the signal to adjust the exhaust gas recirculation valve.
OPERATION
The ECM uses the mass air flow (MAF) sensor to measure air density. The temperature resistor located at the front of the MAF sensor measures the temperature of the inlet air. By varying the voltage, the electronic circuit regulates the temperature of the heating resistor in the rear so that it is 320° F (160°C) higher than the temperature of the intake air. The temperature at the heating resistor is measured by a sensor resistor in-between.
Because the incoming air has a cooling effect, the greater the amount of air that flows in, then the higher the voltage of the heating resistor. The heating resistor is therefore a measure of mass of air flowing past. If a temperature change occurs as a result of a increase or reduction of air flow, the ECM corrects the voltage at the heating resistor until the temperature difference is again achieved. This control voltage is use by the ECM as a unit measure for metered air mass.
REMOVAL
1. Disconnect the negative battery cable.
2. Detach the air hose at the Mass Air Flow (MAF) sensor
3. Unplug the MAF wiring harness connector.
4. Remove the screws retaining the MAF sensor to the air cleaner housing, and remove MAF sensor.
INSTALLATION
1. Position the MAF sensor (4) to air cleaner housing (5) and install the retaining screws.
2. Connect the air intake hose (2) to the MAF sensor and tighten clamp (3).
3. Connect the MAF wiring harness connector (1).
4. Connect negative battery cable.