Line Pressure Test

Fig 1: Identifying Line Pressure Tap & Transmission Fluid Drain Plug

Courtesy of FORD MOTOR CO.

Item	Part Number	Description
1	-	Line pressure tap
2	-	Transmission fluid drain plug

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

NOTE: Do not mistake the transmission fluid drain plug for the line pressure tap plug or the transmission fluid will have to be refilled.

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	Line
Pressures at Idle ^a
P	379-448 kPa (55-65 psi)
R	655-724 kPa (95-105 psi)
N	379-448 kPa (55-65 psi)
D	552-621 kPa (80-90 psi)
L	552-621 kPa (80-90 psi)
Pressure at Wide Open Throttle (WOT) Stall ^a
P	379-448 kPa (55-65 psi)
R	2,034-2,206 kPa (295-320 psi)
N	379-448 kPa (55-65 psi)
D	1,689-1,758 kPa (245-255 psi)
L	1,689-1,758 kPa (245-255 psi)

^a All pressures are approximate.

If the line pressure is not within specification, go to Pinpoint Test A to diagnose the Line Pressure Control (LPC) operation. If LPC operation is OK, see the Line Pressure Diagnosis Chart for line pressure concern causes.
When the pressure tests are completed, install the pressure tap plug.
- Tighten to 9 Nm (80 lb-in).

LINE PRESSURE DIAGNOSIS CHART

Test Results	Possible Source
HIGH at IDLE - ALL RANGES	Wiring Harnesses Line Pressure Control (LPC) 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