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Home >> Mercury >> 2003 >> Marauder >> Repair and Diagnosis >> Transmission >> Automatic Trans >> Automatic Transmission >> Diagnosis And Testing >> Special Testing Procedures >> Line Pressure Test

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 WOT in any transmission range for more than five seconds.

This test verifies that the line pressure is within specification.

  1. Connect pressure gauge to line pressure tap.
  2. 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
    G01608162Courtesy of FORD MOTOR CO.
    Fig 2: Clutch Pressure Chart (1 Of 2)
    G01608163Courtesy of FORD MOTOR CO.
    Fig 3: Clutch Pressure Chart (2 Of 2)
    G01608164Courtesy of FORD MOTOR CO.

    I EPC readings will vary due to EEC strategy. These values are approximate pressures. Actual clutch apply pressures should be within 69-103 kPa (10-15 psi) of line pressure. For additional information on testing, refer to the CLUTCH PRESSURE TEST .

  3. Place the ignition switch in the OFF position. If line pressure is not within specification, check EPC pressure.
  4. Connect pressure gauge to EPC pressure tap.
  5. Start engine and check EPC pressure. Refer to the Line Pressure ChartFig 1 for specifications.
  6. If EPC pressure is not within specification, GO to PINPOINT TEST E  to diagnose EPC operation.

    If EPC operation is OK, refer to the Line Pressure Diagnosis Chart for line pressure concern causes.

    Fig 4: Line Pressure Diagnosis Chart (1 Of 2)
    G01608165Courtesy of FORD MOTOR CO.
    Fig 5: Line Pressure Diagnosis Chart (2 Of 2)
    G01608166Courtesy of FORD MOTOR CO.