Q: What does the MAF sensor measure and how is it used in the engine?
A: The MAF sensor measures the amount of air passing through the sensor body and ultimately entering the engine through the throttle body. The PCM uses this information to control fuel delivery-the more air entering the engine (acceleration), the more fuel required. Only 1996 through 2000 models are equipped with a MAF sensor. The Mass Airflow Sensor (MAF) is located on the air filter housing. A scan tool is necessary to check the output of the MAF sensor. The scan tool displays the sensor output in grams per second. With the engine idling at normal operating temperature, the display should read approximately 4.0 to 9.0 grams per second. When the engine is accelerated the values should rise quickly and remain steady at a steady engine speed. Before checking the MAF sensor operation, check the voltage supply and ground circuits. Disconnect the electrical connector from the MAF sensor and connect the positive lead of a voltmeter to the pink wire terminal at the negative lead to the black/white wire terminal at the harness connector. Tum the ignition key ON-the voltage should read approximately 12.0 volts. If the voltage is incorrect, check the circuits from the MAP sensor to the power distribution center and engine ground point (don't forget to check the fuses first). If the power and ground circuits are good, check the MAF sensor operation with a scan tool. If the MAF sensor does not respond, replace the MAF sensor. To replace, disconnect the electrical connector from the MAF sensor. Loosen the hose clamp securing the air intake duct to the MAF sensor and remove the duct. Loosen the hose clamp retaining the MAF sensor to the air filter cover and remove the sensor. Handle the MAF sensor with care. Damage to this sensor will affect the operation of the entire fuel injection system. Installation is the reverse of removal.