Line Pressure Test

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

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

NOTE: The line pressure tap is used to verify output pressure from PC A or PC B by turning either one off while verifying the output from the other solenoid. The second pressure tap is used to verify the output from the PC C solenoid.

This test verifies that the line pressure is within specifications.

Fig 1: Identifying Pressure Control Tap

Courtesy of FORD MOTOR CO.

Connect pressure gauge to the line pressure tap.

Start engine and check line pressures. Refer to the following Line Pressure Chart for the correct specification.

LINE PRESSURE CHART 4.0L

Transmission Model/Application	Range	Idle		WOT Stall
Transmission Model/Application	Range	PC C	Line	PC C	Line
4.0L	R	621-827 kPa (90-120 psi)	690-965 kPa (100-140 psi)	772-924 kPa (112-134 psi)	1,944-2,620 kPa (282-380 psi)
	N	0-103 kPa (0-15 psi)	621-827 kPa (90-120 psi)
	(D) 3, 2, 1	0-103 kPa (0-15 psi)	621-758 kPa (90-110 psi)	0-103 kPa (0-15 psi)	1,572-1,813 kPa (228-263 psi)

LINE PRESSURE CHART 4.6L

Transmission Model/Application	Range	Idle		WOT Stall
Transmission Model/Application	Range	PC C	Line	PC C	Line
4.6L	R	621-827 kPa (90-120 psi)	621-827 kPa (90-120 psi)	772-924 kPa (112-134 psi)	1,944-2,620 kPa (282-380 psi)
	N	0-103 kPa (0-15 psi)	621-827 kPa (90-120 psi)
	(D) 3, 2, 1	0-103 kPa (0-15 psi)	522-758 kPa (80-110 psi)	0-103 kPa (0-15 psi)	1,572-1,813 kPa (228-263 psi)

If line pressure is not within specifications, check PC C pressure.

Fig 2: Identifying Pressure Control (PC C) Tap
Courtesy of FORD MOTOR CO.
Connect Pressure Gauge to PC C pressure tap.
Start engine and check PC C pressure. Refer to LINE PRESSURE DIAGNOSIS CHART for the correct specification.
If PC C pressure is not within specification, carry out PINPOINT TEST D to diagnose PC C operation. If PC C operation is OK, refer to LINE PRESSURE DIAGNOSIS CHART for line pressure concern causes.