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Line Pressure Test: Notes

Fig 1: Identifying Line And Electronic Pressure Control Pressure Taps
G03244485Courtesy of FORD MOTOR CO.
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 the Stall Speed Test or further transaxle damage will occur. Do not maintain wide open throttle in any transaxle range for more than five seconds.

This test verifies that the line pressure is within specification.

  1. Connect a pressure gauge to the line pressure tap.
  2. 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 EPC Line
    Pressures at Idle  (1) 
    P 10-20 60-84
    R 10-20 78-108
    N 10-20 60-84
    D 10-20 56-84
    3 30-40 102-138
    1 15-40 67-155
    Pressure at Wide Open Throttle (WOT) Stall  a 
    p - -
    R 70-90 265-328
    N - -
    D 70-90 208-257
    3 70-90 208-257
    1 70-90 208-257

    (1) All pressures are in PSI and are approximate.

  3. If the line pressure is not within specification, check EPC pressure.
  4. Connect a pressure gauge to the EPC pressure tap.
  5. Start the engine and check the EPC pressure see the LINE PRESSURE CHART .
  6. If the EPC pressure is not within specification, Go To PINPOINT TEST E: ELECTRONIC PRESSURE CONTROL (EPC) SOLENOID  to diagnose the EPC operation. If EPC operation is OK see LINE PRESSURE DIAGNOSIS CHART  for line pressure concern causes.