Line Pressure Test

WARNING: This page is about a different car, the 2011 Ford F550 Super Duty and 2011 Ford F450 Super Duty. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: Identifying Line Pressure Tap

Courtesy of FORD MOTOR CO.

ITEM DESCRIPTION

Item	Description
1	Line pressure tap

WARNING: Block all wheels, set the parking brake and firmly apply the service brake to reduce the risk of vehicle movement during this procedure. Failure to follow these instructions may result in serious personal injury.

NOTE: Carry out the Line Pressure Test prior to carrying out the Stall Speed Test. Refer to SPECIAL TESTING PROCEDURES . If line pressure is low, do not carry out the Stall Speed Test or additional transmission damage will occur. Do not maintain Wide Open Throttle (WOT) in any transmission range for more than 5 seconds or transmission damage may occur.

NOTE: Certain input sensor failures may cause high line pressure and Failure Mode Effect Management actions. Make sure that the On-Board Diagnostic (OBD) test and electrical repairs have been carried out or test results may be incorrect.

This test verifies the line pressure is within specifications.

Connect the Transmission Fluid Pressure Gauge to the line pressure tap.
Start the engine and check the line pressures at idle speeds with the transmission in each gear range. Refer to the following Pressure Charts to determine if the line pressure is within specification.
Check line pressure at WOT stall speed with the selector lever in all gear ranges. Slowly press the accelerator pedal to WOT and record the pressure reading. After recording the pressure reading, slowly release the accelerator pedal until closed throttle is obtained (idle). Refer to the following Pressure Charts to determine if the line pressure is within specification.
If pressure is not within specification, refer to the LINE PRESSURE DIAGNOSTIC CHART for further diagnosis.
When the line pressure test is completed, install the line pressure tap plug.
- Tighten to 12 Nm (106 lb-in).

LINE PRESSURE DIAGNOSTIC CHART

Test Results	Possible Source
High line pressure at idle all ranges	Wiring harness (external or internal) Pressure Control Solenoid A (PCA) Main regulator valve in pump stuck
Low line pressure at idle all ranges	PCA concerns Low transmission fluid level Blown out solenoid gasket filter Line pressure blow off valve stuck open (on solenoid body assembly) Cross leaks due to loose bolts on the solenoid body Restricted or damage sump filter Sticking pump regulator valve
Low line pressure in M1 and M3 only	Wiring harness (external or internal) Shift Solenoid Pressure Control A (SSPCA) Coast clutch assembly
Low line pressure in M2 only	Wiring harness (external or internal) Shift Solenoid Pressure Control B (SSPCB) Overdrive clutch assembly
Low line pressure in M3 only	Wiring harness (external or internal) Shift Solenoid Pressure Control C (SSPCC) Intermediate clutch assembly
Low line pressure in R only	Wiring harness (external or internal) Shift Solenoid Pressure Control D (SSPCD) Direct clutch assembly Shift Solenoid Pressure Control E (SSPCE) Low/reverse clutch assembly