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Home >> Mercury >> 2005 >> Sable Platinum Edition >> Repair and Diagnosis >> External Pages >> Different car >> Section 796 (Automatic Transmission - 5R110W -- F250-F550 Super Duty) >> Diagnostic Tests >> Special Testing Procedures >> Line Pressure Test

Line Pressure Test

WARNING: This page is about a different car, the 2007 Ford Pickup, 2007 Ford F550 Super Duty, 2007 Ford F450 Super Duty, and 2007 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Locating Line Pressure Test Tap
GF0006776Courtesy of FORD MOTOR CO.
Item Part Number Description
1 - Line pressure tap
CAUTION: Carry out the Line Pressure Test prior to carrying out the Stall Speed Test. If line pressure is low at stall, do not carry out the Stall Speed Test or additional transmission damage will occur. Do not maintain wide-open throttle (WOT) in any transmission range for more than 5 seconds or transmission damage may occur.
CAUTION: Apply the parking brake and block drive wheels during the line pressure test. Vehicle movement during the test may cause personal injury or damage to the vehicle and equipment.
NOTE: Certain sensor failures may cause high control pressure and failure mode effect management (FMEM) actions. Make sure that on-board diagnostic and electrical repairs have been carried out or test results may be incorrect.

This test verifies the line pressure is within specifications.

  1. Connect the pressure gauge to the line pressure tap.
  2. Start the engine and check the line pressures at idle speeds with the transmission in each gear range. Refer to the following Pressure Charts to determine if the line pressure is within specification.
    3. CAUTION: Do not immediately press the throttle to the floor or allow the throttle to immediately close or internal damage to the engine or transmission will occur.
  3. Check line pressure at wide open throttle (WOT) stall speed with the range selector lever in all gear ranges. Slowly press the throttle to WOT and record the pressure reading. After recording the pressure reading, slowly release the throttle until closed throttle is obtained (idle). Refer to the following Pressure Chart charts to determine if the line pressure is within specification.
  4. If pressure is not within specification, refer to the Line Pressure Diagnostic Chart for further diagnosis.
NOTE: Actual and commanded pressures will vary based on calibration and transmission adaptive strategies. All pressures listed are approximate.
PRESSURE CHART A - DIESEL

Gear Line Pressure - kPa (psi) Commanded (a) - PC A pressure kPa (psi)
Idle WOT Stall Idle WOT Stall
P, N 344 (50) - 172 (25) -
R 689 (100) 2,206 (320) 413 (60) 1,407 (204)
Overdrive (Circle D) 483 (70) 2,206 (320) 276 (40) 1,379 (200)
3 551 (80) 1,793 (260) 331 (48) 1,172 (170)
2 551 (80) 1,482 (215) 338 (49) 952 (138)
1 551 (80) 1,861 (270) 338 (49) 1,213 (176)
(a) = Commanded pressure as viewed on diagnostic equipment.
NOTE: Actual and commanded pressures will vary based on calibration and transmission adaptive strategies. All pressures listed are approximate.
PRESSURE CHART B - DIESEL

Gear Commanded (a) - SSPC-A pressure kPa (psi) Commanded (a) - SSPC-B pressure kPa (psi)
Idle WOT Stall Idle WOT Stall
P, N 0 - 0 -
R 758 (110) 2,068 (300) 0 0
Overdrive (Circle D) 0 0 0 0
3 572 (83) 1,765 (256) 0 0
2 0 0 586 (85) 1,461 (212)
1 572 (83) 1,765 (256) 0 0
(a) = Commanded pressure as viewed on diagnostic equipment.
NOTE: Actual and commanded pressures will vary based on calibration and transmission adaptive strategies. All pressures listed are approximate.
PRESSURE CHART C - DIESEL

Gear Commanded (a) - SSPC-C pressure kPa (psi) Commanded (a) - SSPC-D pressure kPa (psi)
Idle WOT Stall Idle WOT Stall
P, N 0 - 0 -
R 0 0 0 (b) 0 (b)
Overdrive (Circle D) 0 0 0 0
3 572 (83) 1,765 (256) 0 0
2 0 0 0 0
1 0 0 0 0
(a) = Commanded pressure as viewed on diagnostic equipment.
(b) = SSPC-D commanded pressure as viewed on diagnostic equipment will be zero. The manual valve controls pressure to the direct clutch in the R detent position. To confirm the presence of the direct clutch pressure monitor the pressure switch PS-D, PS-D should be open in the R position.
NOTE: Actual and commanded pressures will vary based on calibration and transmission adaptive strategies. All pressures listed are approximate.
PRESSURE CHART D - DIESEL

Gear Commanded (a) - SSPC-E pressure kPa (psi)
Idle WOT Stall
P, N 207 (30) -
R 758 (110) 0
Overdrive (Circle D) 207 (30) 0
3 0 0
2 586 (85) 1,461 (212)
1 572 (83) 1,765 (256)
(a) = Commanded pressure as viewed on diagnostic equipment.
NOTE: Actual and commanded pressures will vary based on calibration and transmission adaptive strategies. All pressures listed are approximate.
PRESSURE CHART A - GASOLINE

Gear Line Pressure - kPa (psi) Commanded (a) - PC A pressure kPa (psi)
Idle WOT Stall Idle WOT Stall
P, N 413 (60) - 248 (36) -
R 655 (95) 1,585 (230) 413 (60) 1,068 (155)
Overdrive (Circle D) 455 (66) 1,241 (180) 276 (40) 827 (120)
3 530 (77) 1,241 (180) 331 (48) 862 (125)
2 545 (79) 758 (110) 345 (50) 689 (100)
1 413 (60) 1,275 (185) 248 (36) 862 (125)
(a) = Commanded pressure as viewed on diagnostic equipment.
NOTE: Actual and commanded pressures will vary based on calibration and transmission adaptive strategies. All pressures listed are approximate.
PRESSURE CHART B - GASOLINE

Gear Commanded (a) - SSPC-A pressure kPa (psi) Commanded (a) - SSPC-B pressure kPa (psi)
Idle WOT Stall Idle WOT Stall
P, N 0 - 0 -
R 689 (100) 1,655 (240) 0 0
Overdrive (Circle D) 0 0 0 0
3 572 (83) 1,331 (193) 0 0
2 0 0 586 (85) 1,103 (160)
1 448 (65) 1,331 (193) 0 0
(a) = Commanded pressure as viewed on diagnostic equipment.
NOTE: Actual and commanded pressures will vary based on calibration and transmission adaptive strategies. All pressures listed are approximate.
PRESSURE CHART C - GASOLINE

Gear Commanded (a) - SSPC-C pressure kPa (psi) Commanded (a) - SSPC-D pressure kPa (psi)
Idle WOT Stall Idle WOT Stall
P, N 0 - 0 -
R 0 0 0 (b) 0 (b)
Overdrive (Circle D) 0 0 0 0
3 572 (83) 1,310 (190) 0 0
2 0 0 0 0
1 0 0 0 0
(a) = Commanded pressure as viewed on diagnostic equipment.
(b) = SSPC-D commanded pressure as viewed on diagnostic equipment will be zero. The manual valve controls pressure to the direct clutch in the R detent position.
NOTE: Actual and commanded pressures will vary based on calibration and transmission adaptive strategies. All pressures listed are approximate.
PRESSURE CHART D - GASOLINE

Gear Commanded (a) - SSPC-E pressure kPa (psi)
Idle WOT Stall
P, N 1,034 (150) -
R 1,186 (172) 2,068 (300)
Overdrive (Circle D) 207 (30) 0
3 0 0
2 1,103 (160) 1,620 (235)
1 965 (140) 1,862 (270)
(a) = Commanded pressure as viewed on diagnostic equipment.
LINE PRESSURE DIAGNOSTIC CHART

Test Results Possible Source
High line pressure at idle all ranges
  • Wiring harness (external or internal)
  • PC A solenoid
  • Main regulator valve in pump stuck
Low line pressure at idle all ranges
  • PC A solenoid concerns
  • Low fluid level
  • Blown out solenoid gasket filter
  • Line pressure blow off valve stuck open (on solenoid body assembly)
  • Cross leaks due to loose bolts on the solenoid body
  • Line pressure air bleed check valve in pump stuck open
  • Restricted or damage sump filter
  • Sticking pump regulator valve
Low coast clutch pressure
  • Wiring harness (external or internal)
  • SSPC-A solenoid
  • Coast clutch assembly
Low overdrive clutch pressure
  • Wiring harness (external or internal)
  • SSPC-B solenoid
  • Overdrive clutch assembly
Low intermediate clutch pressure
  • Wiring harness (external or internal)
  • SSPC-C solenoid
  • Intermediate clutch assembly
Low direct clutch pressure
  • Wiring harness (external or internal)
  • SSPC-D solenoid
  • Direct clutch assembly
Low low/reverse clutch pressure
  • Wiring harness (external or internal)
  • SSPC-E solenoid
  • Low/reverse clutch assembly
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