Line Pressure Test

CAUTION: Carry out the Line Pressure Test prior to carrying out the Stall Speed Test. If 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 gear range for more than 5 seconds.

NOTE: Certain sensor failures may cause high PC, FMEM (Failure Mode Effect Management) actions. Make sure that self-test and electrical repairs have been carried out, or test results may be incorrect.

This test verifies that the line pressure is within specifications.

Connect pressure gauge to the line pressure tap.
Start engine and check line pressures. Refer to the LINE PRESSURE CHART to determine if line pressure is within specifications.
If line pressure is not within specification, refer to LINE PRESSURE DIAGNOSIS CHART for line pressure concern causes.

Fig 1: Identifying Line Pressure Tap

Courtesy of FORD MOTOR CO.

Item	Part Number	Description
1	W701515-S309	Line pressure tap

LINE PRESSURE CHART

Trans.	Range	Idle		Stall
4F27E	P, N	345-450 kPa	50-65 psi	N/A	N/A
	R	450-585 kPa	65-85 psi	1,930-2,310 kPa	280-335 psi
	D, 2, 1	345-450 kPa	50-65 psi	1,240-1,450 kPa	180-210 psi

LINE PRESSURE DIAGNOSIS CHART

Test Results	Possible Source
Low pressure in all ranges	Worn pump.
Low pressure in all ranges	Fluid leaking from pump, main control valve body or transaxle case.
Low pressure in all ranges	Pressure control solenoid inoperative.
Low pressure in all ranges	Solenoid regulating valve sticking.
Low pressure in D, 2, 1 only	Fluid leaking from forward clutch hydraulic circuit.
Low pressure in 2	Fluid leaking from intermediate/overdrive band hydraulic circuit.
Low pressure in 1, R only	Fluid leaking from low/reverse clutch hydraulic circuit.
Low in R only	Fluid leaking from reverse clutch hydraulic circuit.
High pressure in all ranges	Pressure control solenoid inoperative or open wire harness.
High pressure in all ranges	Pressure regulator valve sticking.
High pressure in all ranges	PCM inoperative.