Line Pressure Test

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

Fig 1: Line Pressure Chart
Courtesy of FORD MOTOR CO.
Place the ignition switch in the OFF position. If line pressure is not within specification, check EPC pressure.
Connect pressure gauge to EPC pressure tap.
Start engine and check EPC pressure. Use the Line Pressure Chart for specifications.
If EPC pressure is not within specification, Go To PINPOINT TEST E: OUTPUT SHAFT SPEED (OSS) SENSORS to diagnose EPC operation. If EPC operation is OK, see the Line Pressure Diagnosis Chart for line pressure concern causes.

LINE PRESSURE DIAGNOSIS

Test Results	Possible Source
High At Idle - In All Positions	Wiring Harnesses
	Run Quick Test. Refer to INTRODUCTION - CNG, FLEX-FUEL & GASOLINE .
	EPC Solenoid Main Regulator Valve
Low At Idle - In All Positions	Low Fluid Level
	Control Bodies
	Leakage in Pump
	Damaged Gaskets on Separator Valve
	Damaged Separator Plate
	Restricted Inlet Filter
	Case Bolts
	Loose Main Control Valve Body
	EPC Solenoid Bracket
	EPC Solenoid O-Ring
	Case
	Sticking Main Regulator Valve Damaged Inlet Tube Seal on Inlet Filter
Low in Park Only	Valve Body Low/Reverse Servo
Low in Reverse Only	Separator Plate
	Low/Reverse Servo or Valve Body Reverse Clutch
Low in Neutral Only	Valve Body
Low in Overdrive Only	Forward Clutch Valve Body
Low in 1st Position Only	Forward Clutch
	Valve Body Low/Reverse Servo
Low in 2nd Only	Intermediate Clutch
	Valve Bodies Forward Clutch