Fuel Tank Pressure Sensor

WARNING: This page is about a different variant/trim than selected.

Check that the fuel tank pressure sensor does not have deformation, cracks or other damages.
Connect dry-cell battery positive terminal to terminal No. 3 and dry-cell battery ground terminal to terminal No. 1, circuit tester positive terminal to terminal No. 2 and the circuit tester negative terminal to terminal No. 1.
NOTE:
- Use new dry-cell batteries.
- Using circuit tester, check the voltage of a single dry-cell battery is 1.6 V or more. And also check the voltage of three batteries in series is between 4.8 V and 5.2 V.
  
  Fig 1: Connecting Dry-Cell Battery Positive Terminal To Terminal No. 3 And Dry-Cell Battery Ground Terminal To Terminal No. 1
  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 SPECIFICATIONS

Terminal No.	Standard
2 (+) and 1 (-)	Approx. 2.5 V (when 25°C (77°F))

Connect the Mighty Vac to the pressure port (A) on the fuel tank pressure sensor.

Fig 2: Identifying Pressure Port
Courtesy of SUBARU OF AMERICA, INC.

Check the voltage when generating vacuum and positive pressure using Mighty Vac.

CAUTION: Be sure to apply pressure within a range of -10 - 20 kPa (-0.1 - 0.2 kgf/cm² , -1.45 - 2.90 psi). Otherwise the fuel tank pressure sensor will be damaged.

PRESSURE CHART

Pressure	Terminal No.	Standard
-6.67 kPa (-0.07 kgf/cm² , - 0.97 psi)	2 (+) and 1 (-)	Approx. 0.5 V (when 25°C (77°F))
6.67 kPa (0.07 kgf/cm² , 0.97 psi)	2 (+) and 1 (-)	Approx. 4.5 V (when 25°C (77°F))