Line Pressure Test

WARNING: This page is about a different car, the 2018 Lincoln Navigator. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: 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 transmission damage will occur. Do not maintain Wide Open Throttle (WOT) in any transmission range for more than 5 seconds.

This test verifies that the line pressure is within specification.

Courtesy of FORD MOTOR COMPANY

NOTE: The line pressure tap is an M10 X 1.00 thread. Do not use a National Pipe Thread (NPT) fitting when installing a pressure gauge. If a NPT fitting is used, damage to the transmission case will occur.

Connect the Transmission Fluid Pressure Gauge to the line pressure tap using an M10 X 1.00 fitting.

Start the engine and check the line pressures. Refer to the Line Pressure Chart to determine if the line pressure is within specification.

Line Pressure Chart

NOTE: Actual and commanded pressures vary based on calibration and transmission adaptive strategies. All pressures listed are approximate.

Gear	Line Pressure - kPa (psi)		Commanded - LPC pressure kPa (psi) a
Idle	WOT Stall	Idle	WOT Stall
P, N	619 (90)	-	94 (14)	-
R	619 (90)	1, 675 (240)	94 (14)	410 (60)
(D)	619 (90)	1, 600 (230)	94 (14)	375 (55)
3	619 (90)	1, 230 (180)	94 (14)	275 (40)
2	619 (90)	1, 675 (240)	94 (14)	410 (60)
1	619 (90)	1, 600 (230)	94 (14)	375 (55)

Commanded pressure as viewed on diagnostic equipment.

If the line pressure is not within specification, refer to the Line Pressure Diagnosis Chart.
When the pressure tests are complete, install the line pressure tap plug.
1. Tighten to 13.5 Nm (120 lb-in).

Test Results	Possible Source
HIGH at IDLE - ALL RANGES	Wiring harnesses LPC solenoid LPC valve
LOW at IDLE - ALL RANGES	Low fluid level Fluid inlet filter/seal Main control Cross leaks Gaskets Pump Separator plate