Pinpoint Test E: Electronic Pressure Control (EPC) Solenoid
WARNING: This page is about a different car, the 2006 Mercury Mariner and 2006 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.
- E1 ELECTRONIC DIAGNOSTICS
- Key in OFF position.
- Make sure the transaxle vehicle harness connector is fully seated, terminals are fully engaged in connector and in good condition before proceeding.
- Connect the scan tool.
- Key in ON position.
- Carry out KOEO Test until continuous DTCs have been displayed.
- Enter Output Test Mode (OTM). Refer to ON-BOARD DIAGNOSTICS .
- Select the mode ALL ON. Push START to turn outputs on. Push STOP to turn outputs off.
- Does vehicle enter OTM?
Yes: REMAIN in OTM. GO to E2.
No: PRESS START. If vehicle does not enter OTM, REFER to INTRODUCTION - GASOLINE .
- E2 CHECK ELECTRICAL SIGNAL OPERATION CAUTION: Do not pry on the connector. Pull up on the transaxle vehicle harness connector.
- Key in OFF position.
- Disconnect: Transaxle Connector.
- Use a mirror to inspect both ends of connector for damaged or pushed-out pins, corrosion, loose wires and missing or damaged seals.
- Key in ON position.
- Measure the voltage between pin 8 and pin 9 of the transaxle vehicle harness connector.
- While observing VOM, press START and STOP to cycle solenoid output on and off.
- Does the suspect solenoid output voltage change at least 0.5 volt?
Yes: GO to E5.
No: GO to E3.
- E3 CHECK CONTINUITY OF SOLENOID SIGNAL AND VPWR HARNESS CIRCUITS
- Key in OFF position.
- Disconnect: PCM.
- Inspect for damaged or pushed-out pins, corrosion or loose wires.
- Measure the resistance between the PCM pins C35 and C36 and the transaxle harness connector pin 9.
- Measure the resistance between the PCM pin T11 and the transaxle harness connector pin 8.
- Is each resistance less than 5 ohms?
Yes: GO to E4.
No: REPAIR open circuit(s). RECONNECT all components. CLEAR the DTCs and RERUN On-Board Diagnostics.
- E4 CHECK HARNESS FOR SHORT TO POWER AND GROUND
- Key in OFF position.
- Disconnect: Transaxle Connector.
- Measure the resistance between the PCM pin T11 and the PCM pins C35 and C36.
- Measure the resistance between the PCM pin T11 and the PCM pins C47, C48 and C49.
- Measure the resistance between the PCM pin T11 and the PCM pin T41.
- Is each resistance greater than 10,000 ohms?
Yes: : GO to E5.
No: REPAIR short circuit(s). RECONNECT all components. CLEAR the DTCs and RERUN On-Board Diagnostics.
- E5 TRANSAXLE FUNCTIONAL TEST NOTE: LED will turn GREEN when solenoid activates and turn OFF when deactivated. LED will turn RED if activated solenoid/harness is shorted to B+. LED will remain OFF if an activated solenoid/harness is shorted to ground or no continuity (open circuit).
- Connect: PCM.
- Disconnect: Transaxle Connector.
- Install line pressure gauge at line tap on case.
- Connect: Transmission Tester.
- Set Bench/Drive switch to DRIVE mode.
- Rotate gear selector switch to 1st gear position.
- Carry out the EPC Functional Test as outlined in Transmission Tester Manual.
- Observe line pressure on gauge while pressing the EPC switch (engine must be running).
- Does EPC (LED) activate when EPC switch is pressed and line pressure drops?
Yes: INSTALL a new PCM. RERUN On-Board Diagnostics.
No: GO to E6.
- E6 CHECK RESISTANCE OF SOLENOID/HARNESS
- Set Bench/Drive switch to BENCH mode.
- Rotate gear select switch to OHMS CHECK position.
- Measure the resistance between EPC jack and VPWR jack on the Transmission Tester.
- Is resistance between 3.75-5.92 ohms?
Yes: GO to E7.
No: INSTALL a new solenoid body assembly. CLEAR the DTCs. RERUN On-Board Diagnostics tests.
- E7 CHECK SOLENOID/HARNESS FOR SHORT TO GROUND
- Measure the resistance between BAT-jack (engine ground) and EPC, and VPWR/EPC PWR on the transmission tester.
- Is the resistance greater than 10,000 ohms?
Yes: INSTALL a new solenoid body assembly. REFER to MAIN CONTROL VALVE BODY . RECORD and CLEAR the DTCs. RERUN On-Board Diagnostics tests.
No: REFER to DIAGNOSIS BY SYMPTOM .