Line Pressure Test

Fig 1: Line Pressure Taps

Courtesy of FORD MOTOR CO.

Item	Part Number	Description
1	-	Electronic pressure control (EPC) pressure tap
2	-	Line pressure tap

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 5 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 the Line Pressure Chart to determine if the line pressure is within specification.

LINE PRESSURE CHART

Gear	EPC	Line
Pressures at Idle ^a
P	10-20	60-84
R	10-20	78-108
N	10-20	60-84
Overdrive (Circle D)	10-20	56-84
D	10-40	56-138
1	15-40	67-155
Pressure at Wide Open Throttle (WOT) Stall ^a
P	-	-
R	70-90	265-328
N	-	-
Overdrive (Circle D)	70-90	208-257
D	70-90	208-257
1	70-90	208-257

^a All pressures are in PSI and are approximate.

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 Chart for line pressure concern causes.

LINE PRESSURE DIAGNOSIS CHART

Test Results	Possible Source
HIGH at Idle - All Ranges	Wiring harnesses
	EPC solenoid
	Main regulator valve
LOW at Idle - All Ranges	Low fluid level
	Fluid inlet filter/seal
	Main control body
	Cross leaks
	Gaskets
	Pump
	Separator plate
LOW in Park Only	Valve body
LOW in Reverse Only	Separator plate
	Reverse clutch
	Valve body
	Forward clutch
LOW in Neutral Only	Valve body
LOW in Overdrive Only	Forward clutch
	Valve body
LOW in Drive Only	Forward clutch
LOW in Manual 1st Only	Forward clutch
	Valve body