Ford Excursion, Expedition, Lincoln Navigator 2000-2005

Manifold Absolute Pressure Sensor



The most important information for measuring engine fuel requirements comes from the pressure sensor. Using the pressure and temperature data, the PCM calculates the intake air mass. It is connected to the engine intake manifold through a hose and takes readings of the absolute pressure. A piezoelectric crystal changes a voltage input to a frequency output which reflects the pressure in the intake manifold. Atmospheric pressure is measured both when the engine is started and when driving fully loaded, then the pressure sensor information is adjusted accordingly.

Removal & Installation

6.0L Diesel Engine

Make sure the ignition switch is in the OFF position prior to working on the electronic engine controls.

  1. Turn the ignition switch to the OFF position.
  3. Disconnect the electrical connector.
  5. Disconnect the pressure hose.
  7. Remove the mounting screws and the MAP sensor.

To install:

  1. To install, reverse the removal procedure.


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Fig. MAP sensor test schematic

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Fig. MAP sensor altitude/voltage output Relationship

  1. Connect MAP/BARO tester to the sensor connector and sensor harness connector. With ignition ON and engine OFF, use DVOM to measure voltage across tester terminals. If the tester's 4-6V indicator is ON, the reference voltage input to the sensor is okay.
  3. Measure the reference signal of the MAP sensor. If the DVOM voltage reading is as indicated in the table, the sensor is okay.