Repair Procedures: Inspection

Check the continuity between the terminal and the body with an ohmmeter.
If there is no continuity, replace the oil pressure switch.

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Check the continuity between the terminal and the body when the fine wire is pushed.
If there is continuity even when the fine wire is pushed, replace the switch.

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If there is no continuity when a 19.6-39.2 kPa (0.2-0.4kg/cm² , 2.8-5.6 psi) is applied through the oil hole, the switch is operating properly.
Check for air leakage. If air leaks, the diaphragm is broken.

Replace it.