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Home >> Ford >> 2009 >> Flex Limited, FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1919 (Automatic Transmission - Automatic Transaxle/Transmission - 4R70E/4R75E) >> Diagnostic Tests >> Pinpoint Tests - OSC Equipped Vehicle >> Pinpoint Tests >> Pinpoint Test D: Electrical Pressure Control (EPC) Solenoid

Pinpoint Test D: Electrical Pressure Control (EPC) Solenoid

WARNING: This page is about a different car, the 2010 Lincoln Town Car. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: Refer to the Transmission Internal Harness Connector illustration in Transmission Connector Layouts .
NOTE: Read and record all DTCs. All digital transmission range (TR) sensor and vehicle speed sensor (VSS) DTCs must be repaired before entering output state control (OSC).
  1. D1 ELECTRONIC DIAGNOSTICS 
    • Vehicle in PARK.
    • Key in OFF position.
    • Check to make sure the transmission harness connector is fully seated, pins are fully engaged in connector and in good condition before proceeding.
    • Connect the diagnostic tool.
    • Key in ON position.
    • Access the transmission PIDs.
    • Is the scan tool able to access the transmission PIDs? 
    1. YES  : Go to  D2.
    2. NO  : REPEAT procedure to access the transmission PIDs. If the scan tool did not access the transmission PIDs, REFER to the Introduction - Gasoline Engines article for diagnosis of PCM.
  2. D2 SOLENOID FUNCTIONAL TEST 
    • Install a pressure gauge into electronic pressure control (EPC) tap.
    • Monitor pressure gauge.
    • With the engine running, command the LINEDSD# PID to change the line pressure.
    • Does the pressure reading match the commanded pressure? 
    1. YES  : CLEAR DTCs. TEST the system for normal operation.
    2. NO  : Go to  D3.
  3. D3 CHECK FOR BATTERY VOLTAGE 
    • Disconnect: Transmission Harness Connector C1274
    • Key in ON position.
      • Fig 1: Measuring Voltage
      GF0014038Courtesy of FORD MOTOR CO.
    • Measure the voltage between the transmission harness connector C1274-4, circuit 391 (RD/YE), harness side and ground.
    • Is voltage greater than 10 volts? 
    1. YES  : Go to  D4.
    2. NO  : CHECK for open or short circuit in harness.
  4. D4 CHECK FOR BATTERY VOLTAGE 
    • Remove transmission fluid pan.
    • Visually inspect the lead frame connectors for damage.
    • Key in ON position.
      • Fig 2: Measuring Voltage
      GF0003459Courtesy of FORD MOTOR CO.
    • Measure the voltage with the positive lead to the VPWR solenoid pin and the negative lead to a good ground.
    • Is voltage greater than 10 volts? 
    1. YES  : Go to  D5.
    2. NO  : REPAIR the circuit. CLEAR the DTCs. TEST the system for normal operation.
  5. D5 ELECTRICAL SIGNAL CHECK 
      Fig 3: Measuring Voltage
      GF0014039Courtesy of FORD MOTOR CO.
    • Measure the voltage with the positive lead connected to the VPWR solenoid pin and connect the negative lead to the signal pin of the EPC solenoid.
    • Increase and decrease the solenoid duty cycle, while monitoring the voltmeter, and solenoid state on the scan tool, and listen for the solenoid to activate (click).
    • Does the voltage and solenoid state change? 
    1. YES  : Go to  D6.
    2. NO  : CHECK for open or short circuit in harness or PCM.
  6. D6 CHECK MOLDED LEAD FRAME SOLENOID CONNECTIONS 
    • Key in OFF position.
    • Disconnect the molded lead frame.
    • Inspect the molded lead frame for damage.
      • Fig 4: Locating Lead Frame Connector Pins
      G04584207Courtesy of FORD MOTOR CO.
    • Using the special tool, check to make sure that the molded lead frame solenoid connections are making contact with the solenoids. The special tool should not pass through the connectors easily, it should have some resistance.
    • Does the special tool go easily through the molded lead frame connector pins? 
    1. YES  : INSTALL a new molded lead frame and Go to  D7 .
    2. NO  : Go to  D7.
  7. D7 CHECK SOLENOID RESISTANCE AT SOLENOID 
      Fig 5: Measuring Resistance
      GF0003461Courtesy of FORD MOTOR CO.
    • Measure the resistance between the pins of the solenoid.
    • Measure the resistance of the EPC solenoid.
    • Is the resistance between 2.48 and 5.66 ohms? 
    1. YES  : Go to  D8.
    2. NO  : INSTALL a new solenoid. CLEAR the DTCs. TEST the system for normal operation.
  8. D8 CHECK THE SOLENOID FOR A SHORT TO GROUND 
      Fig 6: Checking Continuity
      GF0003462Courtesy of FORD MOTOR CO.
    • Check for continuity between engine GROUND and the EPC solenoid terminals with ohmmeter or other low current tester (less than 200 milliamps). Connection should show infinite resistance (no continuity).
    • Is there continuity? 
    1. YES  : INSTALL a new solenoid. CLEAR the DTCs. TEST the system for normal operation.
    2. NO  : REFER to Diagnosis By Symptom  for diagnosis of pressure concerns.
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