You can learn properly test a Ford MAP sensor.
Ford vehicles are equipped with a digital four-pin manifold absolute pressure (MAP) sensor. The MAP sensor measures the current engine load and relays this information to the engine computer. The engine computer uses the measurements to adjust the fuel-to-air ratio. Ford’s MAP sensor must be tested using a digital volt-ohm meter. The use of a regular ohmmeter can cause serious damage to the electrical components of the sensor.
1. Open the hood of the Ford vehicle. Locate the MAP sensor, which is located on the passenger side of the vehicle. The small black square sensor is mounted on the firewall between the heater assembly and the engine. If needed, the Ford repair manual has a detailed diagram.
2. Connect the lead wire on the digital volt-ohm meter to the signal wire on the sensor. Attach the opposite lead wire to the negative battery terminal. The battery terminal acts as a grounded surface.
3. Turn the engine of the vehicle on. Ask someone to rev the engine. Allow the digital volt-ohm meter to register; you should see the voltage jump. The signal should increase as the vacuum drops. If the sensor does not detect the vacuum activity, the signal will not increase.