Manifold Absolute Pressure Sensor

MANIFOLD ABSOLUTE PRESSURE SENSOR TESTING

NOTE: The following vacuum and pressure values are indicated by relative pressure from atmospheric pressure.




1. Connect the Special Service Tools (Engine Signal Monitor) to the ECM as shown.

CAUTION: Do not apply a vacuum or pressure outside of the specified limits. Doing so will damage the manifold absolute pressure sensor.




2. Apply pressure then a vacuum to the manifold absolute pressure sensor according to the following procedure.
3. Decrease the applied pressure from 100 kPa (29.5 in.Hg) to -86.7 kPa (-25.6 in.Hg) and verify that the ECM terminal 3U voltage decreases accordingly.




NOTE: The output voltage varies with the measuring condition.
- Input voltage - 5.0 V
- Atmospheric pressure - 101.3 kPa (29.9 in.Hg)
- Outside temperature - 25°C (77°F)

4. If not as specified, inspect:
a. Harness continuity.
- Between ECM terminal 3AB and manifold absolute pressure sensor terminal A
- Between ECM terminal 3U and manifold absolute pressure sensor terminal B
- Between ECM terminal 3A and manifold absolute pressure sensor terminal C




b. Terminal voltage (Ignition Switch ON)
- Manifold absolute pressure sensor terminal B voltage: Constant voltage (4.5-5.5 V)
- Manifold absolute pressure sensor terminal A voltage: Ground (Below 1.0 V)

5. If terminal voltage is correct and if there is harness continuity, replace the manifold absolute pressure sensor.