Line Pressure Test: Measurement

NOTE: If the clutch or the brake shows a sign of slippage or shifting sensation is not correct, the line pressure should be checked.

Excessive shocks during upshifting or shifting takes place at a higher point than under normal circumstances, may be due to the line pressure being too high.
Slippage or inability to operate the vehicle may, in most cases, be due to loss of oil pressure for the operation of the clutch, brake or control valve.

Line pressure measurement (under no load):
1. Before measuring line pressure, jack-up all the wheels.
2. Maintain the temperature of ATF at approx. 70 - 80°C (158 - 176°F) during measurement. (ATF will reach the above-mentioned temperature after idling the engine for approx. 30 minutes with the select lever in "N" or "P".)
Line pressure measurement (under heavy load):
1. Before measuring line pressure, apply both the foot and parking brakes with all wheels chocked (Same as for "stall" test conditions).
2. Measure the line pressure when the select lever is in "R" or 2nd of manual mode with engine under stall conditions.
3. Measure the line pressure within 5 seconds after shifting the select lever to each position. (If the line pressure needs to be measured again, allow the engine to idle and cool it down more than 1 minute.)
4. Maintain the ATF temperature at approx. 70 - 80°C (158 - 176°F) during measurement. (ATF will reach the above-mentioned temperature after idling the engine for approx. 30 minutes with the select lever in "N" or "P".)
Remove the test plug and install the ST instead.
ST 498897200 OIL PRESSURE GAUGE ADAPTER

Fig 1: Removing Test Plug
Courtesy of SUBARU OF AMERICA, INC.
Connect the ST1 with ST2.
ST1 498897200 OIL PRESSURE GAUGE ADAPTER

ST2 498575400 OIL PRESSURE GAUGE ASSY
Check for duty ratio changes by adjusting the acceleration pedal position using Subaru Select Monitor.

STANDARD LINE PRESSURE