Line Pressure Test

NOTE: 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 (WOT) in any gear range for more than 5 seconds.

NOTE: Certain sensor failures may cause high line pressure, Failure Mode Effect Management actions. Be sure that the self test and electrical repairs have been completed or test results may be incorrect.

NOTE: The line pressure tap is used to verify output pressure from Pressure Control Solenoid A (PCA) or Pressure Control Solenoid B (PCB) by turning one solenoid off, while verifying the output from the other solenoid. The second pressure tap is used to verify the output from Pressure Control Solenoid C (PCC).

This test verifies that the line pressure is within specification.

Connect the Transmission Fluid Pressure Gauge to the line pressure tap.

Start the engine and check line pressures. Refer to the following LINE PRESSURE CHART to determine if line pressure is within specifications.

Fig 1: Identifying Line Pressure Tap

Courtesy of FORD MOTOR CO.

PART NUMBER REFERENCE

Item	Part Number	Description
1	1390685-S430	Line pressure tap

LINE PRESSURE CHART - 4.0L AND 4.6L ENGINES

Range	Idle Pressure		WOT Stall Pressure
Range	PCC	Line	PCC	Line
N	0-103 kPa (0-15 psi)	758-1,034 kPa (110-150 psi)
R	758-862 kPa (110-125 psi)	965-1,551 kPa (140-225 psi)	758-862 kPa (110-125 psi)	2,000-2,482 kPa (290-360 psi)
(D), 2, 1	0-103 kPa (0-15 psi)	758-1,045 kPa (110-150 psi)	0-103 kPa (0-15 psi)	1,448-1,793 kPa (210-260 psi)

If the line pressure is not within specification, check the PCC pressure.

Connect the Transmission Fluid Pressure Gauge to the PCC pressure tap.

Fig 2: Identifying PCC Pressure Tap

Courtesy of FORD MOTOR CO.

PART NUMBER REFERENCE

Item	Part Number	Description
1	1390685-S430	Pressure Control Solenoid C (PCC) tap

Start the engine and check the PCC pressure. Refer to LINE PRESSURE DIAGNOSIS CHART for specification.
If the PCC pressure is not within specification, GO to PINPOINT TEST D to diagnose PCC operation. If PCC operation is OK, refer to LINE PRESSURE DIAGNOSIS CHART for line pressure concern causes.

When pressure tests are complete, install the pressure tap plugs.

Tighten to 13 Nm (115 lb-in).

LINE PRESSURE DIAGNOSIS CHART

Test Results	Possible Source
High at Idle - All Ranges	Wiring harnesses Pressure Control Solenoid C (PCC) boost valve PCC solenoid Main regulator valve
Low at Idle - All Ranges	Low transmission fluid level Transmission fluid inlet filter/seal Main control body Cross leaks Gaskets Pump Separator plate
Low - All Forward Ranges	Forward clutch Main control Overdrive (O/D) servo Intermediate servo
Low in PARK Only	Valve body
Low in REVERSE Only	Separator plate Rear servo piston, cover seal Reverse clutch O/D servo Intermediate servo Valve body Forward clutch
Low in NEUTRAL Only	Valve body O/D servo Intermediate servo
Low in D Only	Forward clutch O/D servo Intermediate servo Valve body
Low in D Only ((D) Cancelled)	Forward clutch O/D servo Intermediate servo Valve body
Low in 1st Position	Forward clutch Valve body
Low in 2nd Position	Intermediate servo O/D servo Intermediate servo Forward clutch
Low in 3rd Position	Intermediate servo O/D servo Forward clutch