Pinpoint Test D: Electrical Pressure Control (EPC) Solenoid
WARNING: This page is about a different car, the 2007 Lincoln Mark LT and 2007 Ford Pickup. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
Refer to the Transmission Internal Harness illustration Transmission Connector Layouts in this article.
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).
- D1 ELECTRONIC DIAGNOSTICS
- Key in OFF position.
- Select PARK.
- Check to make sure the transmission harness connector is fully seated, pins are fully engaged in the connector and in good condition before proceeding.
- Connect the diagnostic tool.
- Key in ON position.
- Enter the following diagnostic mode on the diagnostic tool: Diagnostic Data Link
- Enter the following diagnostic mode on the diagnostic tool: PCM
- Enter the following diagnostic mode on the diagnostic tool: Active Command Modes
- Enter the following diagnostic mode on the diagnostic tool: Output State Control (OSC)
- Enter the following diagnostic mode on the diagnostic tool: Trans-Bench Mode
- Does the vehicle enter the Trans-Bench Mode?
- YES : Go to D2.
- NO : REPEAT procedure to ENTER Trans-Bench Mode. If vehicle did not enter OSC, REFER to the INTRODUCTION - GASOLINE ENGINES article for diagnosis of PCM.
- D2 SOLENOID FUNCTIONAL TEST
- Install 2,060 kPa (300 psi) pressure gauge into electronic pressure control (EPC) tap.
- Monitor pressure gauge.
- Enter the following diagnostic mode on the diagnostic tool: Parameter; EPC
- Select value - 15, 30, 45, 60, 70 or 90 psi.
- Press "SEND".
- Select another value "0-90 psi".
- Press "SEND".
- Enter the following diagnostic mode on the diagnostic tool: XXX
- Press "SEND".
- Does the pressure reading match the commanded pressure?
- YES : CLEAR DTCs. REPEAT OBD Tests.
- NO : Go to D3.
- D3 CHECK FOR VOLTAGE
- Disconnect: Transmission Harness Connector
- Key in ON position.
- Measure the voltage on pin 6 at the transmission harness connector to chassis ground.
- Is the voltage less than 5 volts?
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- YES : Go to D4.
- NO : REPAIR the circuit.
- D4 CHECK FOR BATTERY VOLTAGE
- Remove transmission fluid pan.
- Visually inspect the lead frame connectors for damage.
- Key in ON position.
- Measure the voltage with positive lead to VPWR solenoid pin and negative lead to a good ground.
- Is voltage greater than 10 volts?
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- YES : Go to D5.
- NO : REPAIR the circuit. CLEAR the DTCs. REPEAT the OBD Tests.
- D5 ELECTRICAL SIGNAL CHECK
- Measure the voltage with positive lead connected to VPWR solenoid pin and connect negative lead to the signal pin of the EPC solenoid.
- Turn the solenoids ON and OFF, while monitoring the voltage reading, solenoid state on the scan tool (ON and OFF), listen for the solenoid to activate (click).
- Enter the following diagnostic mode on the diagnostic tool: Trans-Bench Mode
- Enter the following diagnostic mode on the diagnostic tool: Parameter EPC
- Select a value "0-90 psi".
- Press "SEND".
- Select another value "0-90 psi".
- Press "SEND".
- Enter the following diagnostic mode on the diagnostic tool: XXX
- Press "SEND".
- Does the voltage and solenoid state change?
- YES : Go to D6.
- NO : CHECK for open or short circuit in harness or PCM.
- D6 CHECK MOLDED LEAD FRAME SOLENOID CONNECTIONS
- Key in OFF position.
- Disconnect: Molded Lead Frame
- Inspect the molded lead frame for damage.
- Using the special tool, check all molded lead frame solenoid connections.
- Does the special tool go easily through the molded lead frame connector pins?
- D7 CHECK SOLENOID RESISTANCE AT SOLENOID
- Measure the resistance of the EPC solenoid.
- Is the resistance between 2.48 and 5.66 ohms?
- YES : Go to D8.
- NO : INSTALL a new solenoid. CLEAR the DTCs. REPEAT the OBD Tests.
- D8 CHECK SOLENOID FOR SHORT TO GROUND
- 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?
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- YES : INSTALL a new solenoid. CLEAR the DTCs. REPEAT the OBD Tests.
- NO : REFER to Diagnosis By Symptom in this article for diagnosis of pressure concerns.