Line Pressure

Place oil pressure gauge in driver's compartment. Remove blind plug on floor board/firewall near steering column and pass hose of gauge into engine compartment. Remove line pressure test plug and install oil pressure gauge. See Fig 1 .
Raise and support vehicle on hoist. With ATF at normal operating temperature and correct level, perform line pressure test with throttle fully-closed. Pressures should be within limits. See LINE PRESSURE TEST SPECIFICATIONS table.
Apply both foot and parking brakes and chock all wheels. With ATF at normal operating temperature and correct level, perform line pressure test at Wide Open Throttle (WOT). Measure line pressure within 5 seconds after shifting selector lever to each position. Before measuring again, idle engine for at least one minute. Pressures should be within limits. See LINE PRESSURE TEST SPECIFICATIONS table.

LINE PRESSURE TEST SPECIFICATIONS

Fig 1: Identifying Pressure Ports

Courtesy of SUBARU OF AMERICA, INC.