How Do I Test the Mass Airflow Sensor on a 2001 Explorer Sport Trac 4.0 Liter?
- 1). Turn the ignition key to the "On" position, but do not start the engine. Open the hood and locate the mass air flow sensor near the air cleaner.
- 2). Unplug the electrical connector from the sensor and locate the connector pin labeled "B+." Connect the positive voltmeter lead to the B+ connector pin. Connect the negative voltmeter lead to the connector pin labeled "Ground." The meter should show close to 10 volts.
- 3). Reconnect the sensor wiring harness and use straight pins to probe the wiring with the sensor connected. Start the engine and measure the voltage with the voltmeter. The voltage should read 0.5 to 0.7 volts during idle.
- 4). Increase the engine speed using the throttle body or have an assistant depress the gas pedal. The sensor voltage should increase to 1.5 to 3.0 volts when the engine is higher than idle.
- 5). Check the wiring harness for damage from the sensor to the computer module. If you do not find damage, the sensor may require additional testing at a dealership service department or automobile repair shop using specialized tools.