Line Pressure Test

WARNING: This page is about a different car, the 2003 Mercury Sable and 2003 Ford Taurus. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: Identifying Line Pressure Tab

Courtesy of FORD MOTOR CO.

CAUTION: Carry out the Line Pressure Test prior to carrying out the Stall Speed Test. If the line pressure is low at stall, do not carry out the Stall Speed Test or further transaxle damage will occur. Do not maintain wide open throttle in any transaxle range for more than five seconds.

This test verifies that the line pressure is within specification.

Connect a pressure gauge to the line pressure tap.
Start the engine and check the line pressures see Fig 2 to determine if the line pressure is within specification.

Fig 2: Line Pressure Chart
Courtesy of FORD MOTOR CO.
If the line pressure is not within specification, check EPC pressure.
Connect a pressure gauge to the EPC pressure tap.
Start the engine and check the EPC pressure see the LINE PRESSURE CHART for specifications.
If the EPC pressure is not within specification, GO to PINPOINT TEST E to diagnose the EPC operation. If EPC operation is OK see the Line Pressure Diagnosis Charts for line pressure concern causes.

Fig 3: Line Pressure Diagnosis Chart (1 Of 2)
Courtesy of FORD MOTOR CO.

Fig 4: Line Pressure Diagnosis Chart (2 Of 2)
Courtesy of FORD MOTOR CO.