Line Pressure Test

WARNING: This page is about a different car, the 2005 Ford Pickup. However, it is still accessible from the selected car via links, so may be relevant.

CAUTION: 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 Stall Speed Test or further transmission damage will occur. Do not maintain wide open throttle (WOT) in any transmission range for more than five seconds.

This test verifies that the line pressure is within specification.

Connect a pressure gauge to the line pressure tap.

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

LINE PRESSURE CHART

Application	Range	Idle		WOT
Application	Range	EPC	Line Pressure	EPC	Line Pressure
All	P, N	0-138 kPa (0-20 psi)	207-448 kPa (30-65 psi)	N/A	N/A
	OD, 2, 1	138-345 kPa (20-50 psi)	345-758 kPa (50-110 psi)	655-793 kPa (95-115 psi)	1,310-1,586 kPa (190-230 psi)
	R	138-345 kPa (20-50 psi)	552-1034 kPa (80-150 psi)	552-655 kPa (80-95 psi)	1,379-1,931 kPa (200-280 psi)

Place the ignition switch in the OFF position. If line pressure is not within specification, check EPC pressure.
Connect a pressure gauge to the EPC pressure tap.
Start the engine and check EPC pressure. Use the line pressure chart for specifications.
If the EPC pressure is not within specification, GO to PINPOINT TEST E to diagnose the EPC operation. If the EPC operation is OK, refer to the line pressure diagnosis chart for line pressure concern causes.

LINE PRESSURE DIAGNOSIS CHART

Test Results	Possible Source
HIGH at Idle in All Positions	Wiring Harnesses Run Quick Test. REFER to the INTRODUCTION - GASOLINE article . EPC Solenoid Main Regulator Valve
LOW at Idle in All Positions	Low Fluid Level Restricted Inlet Filter Damaged Inlet Tube Seal on Inlet Filter Loose Main Control Valve Bodies Sticking Main Regulator Valve Excessive Leakage in Pump Damaged Gaskets on Separator Valve Case Bolts Case Separator Plate EPC Solenoid
LOW in Park ONLY	Valve Body Low/Reverse Servo
LOW in Reverse ONLY	Separator Plate Low/Rear Servo or Valve Body Reverse Clutch
LOW in Neutral ONLY	Valve Body
LOW in Overdrive ONLY	Forward Clutch Valve Body
LOW in First Position	Forward Clutch Valve Body Low/Reverse Servo
LOW in Second Position	Intermediate Clutch Valve Body Forward Clutch