Manifold Absolute Pressure Sensor: Inspection

Check that the manifold absolute pressure sensor has no deformation, cracks or other damages.
Using new dry cell batteries, connect the battery positive terminal to terminal No. 3 and the battery ground terminal to terminal No. 2, and connect the circuit tester positive terminal to terminal No. 1 and the circuit tester ground terminal to terminal No. 2.
NOTE:
- Using a circuit tester, check that the initial voltage of each dry-cell battery is 1.6 V or more. And also check that the voltage of three batteries in series is between 4.8 - 5.2 V.
- For power supply, 5 V DC constant voltage power source can also be used.
Fig 1: Checking Manifold Absolute Pressure Sensor Connector Terminals Voltage
Courtesy of SUBARU OF AMERICA, INC.

Check the voltage at a normal atmospheric pressure.

NOTE: The atmospheric pressure at higher altitude is lower than normal. Therefore, the voltage is lower than the standard value.

Terminal No.	Standard
1 (+) and 2 (-)	Approx. 4.65 V (when 25°C (77°F))

Connect the Mighty Vac to the pressure port (A) of manifold absolute pressure sensor.

Fig 2: Locating Manifold Absolute Pressure Sensor Pressure Port
Courtesy of SUBARU OF AMERICA, INC.

Check the voltage when generating vacuum using Mighty Vac.

CAUTION: Do not apply a vacuum that exceeds -105 kPa (-1.07 kg/cm² , -15.2 psi). Doing so may damage the manifold absolute pressure sensor.

NOTE: When vacuum occurs at the pressure port of manifold absolute pressure sensor, the voltage will drop from the value as in step 3).

Pressure	Terminal No.	Standard
-105 kPa (-1.07 kg/cm² , -15.2 psi)	1 (+) and 2 (-)	Approx. 0.4 V (when 25°C (77°F))