Line Pressure Test

CAUTION: Carry out Line Pressure Test prior to carrying out Stall Speed Test. If 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 in any gear range for more than five seconds.

NOTE: Certain sensor failures may cause high PC, FMEM (Failure Mode Effect Management) actions. Be sure that self test and electrical repairs have been carried out, or test results may be incorrect.

NOTE: The line pressure tap is used to verify output pressure from PC A or PC B by turning either one off while verifying the output from the other solenoid. The second pressure tap is used to verify the output from the PC C solenoid.

This test verifies that the line pressure is within specifications.

Fig 1: Locating Line Pressure Tap

Courtesy of FORD MOTOR CO.

Connect pressure gauge to the line pressure tap.
Start engine and check line pressures. Refer to the following Line Pressure Chart for the correct specification.

Fig 2: Line Pressure Chart
Courtesy of FORD MOTOR CO.
If line pressure is not within specifications, check PC C pressure.

Fig 3: Locating Pressure Control PC C Tap
Courtesy of FORD MOTOR CO.
Connect Pressure Gauge to PC C pressure tap.
Start engine and check PC C pressure. Refer to Line Pressure Diagnosis Chart for the correct specification.
If PC C pressure is not within specification, carry out PINPOINT TEST D to diagnose PC C operation. If PC C operation is OK, refer to Line Pressure Diagnosis Chart for line pressure concern causes.