OD light flashing

[bacernate]

Went out to go home from work and the OD light was flashing. Car shifted very ******* the way home, absolutely no lockup at all.
Got the x-3 out today and pulled a p1744 and a p1746. I know what the 1744 is but what the heck is a p1746?
Any help would be appreciated, and please pray to the tranny gods for me.:thankyou:

 

[SHOZ123]

DTC 1746 is the EPC solenoid not working. Either a bad coil on the solenoid or bad wiring between the PCM and the solenoid coil. May be the harness inside the tranny. You can check the harness to the solenoid from the connector on top of the tranny. The red wire is 12V+ power to the solenoid and the White/Yellow would be the ground. Should be 3.23-5.5 ohms.

P1746 - EPC

Open PCM output driver Voltage through EPC solenoid is checked and compared to a voltage through solenoid after a time delay. An error will be noted if tolerance is exceeded. KOEO and continuous on-board diagnostic. Open Circuit — Causes maximum EPC pressure, harsh engagements and shifts (TCIL flashing).

Pinpoint Test E

PINPOINT TEST E: ELECTRONIC PRESSURE CONTROL (EPC) SOLENOID

NOTE: Refer to the Transmission Internal Harness illustration preceding these pinpoint tests.



NOTE: Refer to the Transmission Harness Connector illustration preceding these pinpoint tests.




E1 AX4N - ELECTRONIC DIAGNOSTICS
Check to make sure the transaxle vehicle harness connector C168 is fully seated, terminals are fully engaged in connector and in good condition before proceeding.
Connect New Generation Star Tester 007-00500 or equivalent to transaxle vehicle harness connector.
Perform KOEO Test until continuous DTCs have been displayed.
Enter Output Test Mode (OTM).
Select the mode ALL ON.
Press START to turn outputs ON.
Push STOP to turn outputs OFF.
Does vehicle enter OTM?
Yes No
REMAIN in OTM. GO to E2 . PRESS START. If vehicle does not enter OTM, REFER to Powertrain Control/Emissions Diagnosis Manual Output Test Mode NOT FUNCTIONING, Pinpoint Test MB.

E2 CHECK ELECTRICAL SIGNAL OPERATION
CAUTION: Do not pry on connector. This will damage the connector and could result in a transaxle concern. Press button and pull up on transaxle harness connector.

Disconnect transaxle vehicle harness connector C168 .
Using a mirror, inspect both ends of connector for damage or pushed out pins, corrosion, loose wires and missing or damaged seals.
Connect a voltmeter positive lead to VPWR Pin C168 and the negative lead to the solenoid circuit Pin C168 of the transaxle vehicle harness connector C168 .
Place voltmeter on 20 volt scale.
While observing voltmeter, press START and STOP to cycle solenoid output ON and OFF.
Does the suspect solenoid output voltage change at least 0.5 volts?
Yes No
GO to E5 . GO to E3 .

E3 CHECK CONTINUITY OF SOLENOID SIGNAL AND VPWR HARNESS CIRCUITS
Turn ignition switch OFF.
Disconnect powertrain control module. Inspect for damaged or pushed out pins, corrosion, or loose wires.
Install Rotunda 104-Pin Breakout Box 014-00950 or equivalent. Leave powertrain control module disconnected.
Measure resistance between PCM Test Pins 71/97 at breakout box and EPC PWR circuit at transaxle harness connector Pin C168 , Pin C168 .
Measure resistance between PCM Test Pin 81 at breakout box and EPC signal pin at transaxle harness connector Pin C168 .
Is each resistance less than 5.0 ohms?
Yes No
GO to E4 . SERVICE OPEN circuit(s). REMOVE breakout box. RECONNECT all components. ERASE DTCs and repeat On-Board Diagnostics.

E4 CHECK HARNESS FOR SHORT TO POWER AND GROUND
Turn ignition switch OFF.
Make sure Rotunda 104-Pin Breakout Box 014-00950 or equivalent is installed, powertrain control module is disconnected.
Make sure transaxle harness connector is disconnected.
Measure resistance between EPC circuit PCM Test Pin 81 and 71/97 at breakout box.
Measure resistance between EPC circuit PCM Test Pin 81 and Pins 24/51/76/77/103, 91 at breakout box.
Is each resistance greater than 10,000 ohms?
Yes No
GO to E5 . SERVICE SHORT circuit(s). REMOVE breakout box. RECONNECT all components. ERASE DTCs and REPEAT On-Board Diagnostics.

E5 TRANSAXLE FUNCTIONAL TEST
Connect powertrain control module.
Disconnect transaxle harness connector C168 .
Install line pressure gauge at line tap on case.
Install Rotunda Transmission Tester AX4N Compatible 007-00130 and AX4N Cable and Overlay 007-00117 or equivalent to transaxle connector.
Set Bench/Drive switch to DRIVE mode.
Rotate gear selector switch to first gear position.
Using tests described under Rotunda Transmission Tester , perform EPC voltage 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).



Observe line pressure on gauge while pressing the EPC switch (engine must be running).
Does EPC (LED) activate when EPC switch is pressed?
Yes No
REPLACE powertrain control module. INSPECT PCM power relay, SERVICE as required. REPEAT On-Board Diagnostics. GO to E6

E6 CHECK RESISTANCE OF SOLENOID/HARNESS
Set Bench/Drive switch to BENCH mode.
Rotate gear select switch to OHMS CHECK position.
Connect ohmmeter negative lead to EPC jack and positive lead to VPWR jack on tester. This is to test EPC solenoid and harness.
Record resistance.
Is resistance between 3.23-5.5 ohms?
Yes No
GO to E7 Internal harness or solenoid may be damaged. GO to E8

E7 CHECK SOLENOID/HARNESS FOR SHORT TO GROUND
Check for continuity between BAT- jack (engine ground) and appropriate jack with an ohmmeter or other low current tester (less than 200 milliamps).

Solenoid Tester Jack
EPC EPC
VPWR






Connection should show infinite resistance (no continuity).
Is there continuity?
Yes No
GO to E8 REFER to Hydraulic/Mechanical Diagnostic Routines described in Diagnosis By Symptom .

E8 AX4N INTERNAL ELECTRONIC DIAGNOSTICS
Drain transaxle fluid.
Remove transaxle side pan.
Check that the internal harness connector is fully engaged on the EPC solenoid assembly.
Check that internal harness connector terminals are fully seated in the connector.
Inspect the connector for damage.
Is everything engaged and in good condition?
Yes No
GO to E9 SERVICE as required.

E9 CHECK INTERNAL AX4N HARNESS (CONTINUITY)
Disconnect internal harness from the EPC solenoid assembly.
Connect the positive lead from ohmmeter to the tester EPC jack and the negative lead at the blue wire at the EPC connector.
Record resistance. Should be less than 0.5 ohm.
Connect the positive lead from an ohmmeter to the tester VPWR jack and the negative lead at the green wire at the EPC connector.
Record resistance.
Is each resistance less than 0.5 ohm?
Yes No
GO to E10 REPLACE internal harness. GO to E11

E10 CHECK INTERNAL AX4N HARNESS (SHORTS TO GROUND)
Check for continuity between BAT- jack (engine ground) and the appropriate wire with an ohmmeter or other low current tester (less than 200 milliamps).

Solenoid Wire
EPC Green -
Blue+


Connection should show infinite resistance (no continuity).
Is there continuity?
Yes No
REPLACE internal harness. GO to E11 GO to E11

E11 CHECK SOLENOID RESISTANCE
Check solenoid resistance by connecting an ohmmeter at the EPC terminals of the solenoid assembly.
Record resistance.
Is resistance between 3.23-5.5 ohms?
Yes No
GO to E12 REPLACE EPC solenoid.

E12 CHECK SOLENOID FOR SHORT TO GROUND
Check for continuity between BAT-(engine ground) and each EPC terminal with ohmmeter or other low current tester (less than 200 milliamps).

SOLENOID Terminal
EPC +/-


Connection should show infinite resistance (no continuity).
Is there continuity?
Yes No
REPLACE EPC solenoid. REFER to Hydraulic/Mechanical Diagnostic Routines in Diagnosis by Symptom for diagnosis of Pressure Concerns.

 

[bacernate]

Drove it today and no problems at all. Could there be something in my tune? I did find out it was some sort or comunication problem with the pcm and the epc solenoid. Where is the epc located, right in the side cover?
I was going to pull the trans and replace the converter and the tcc solenoid any way, just don't have the cash for a total rebuild.
I would probably use a Jasper reman any way. They are more money but at least i don't have to take mine and have them rebuild it 100 times before they get it right.
Any thoughts on the tune issue Paul? Always has shifted a little too firm on the 1-2 shift but I kind of like it that way!!! But passengers in my car think it's rough.

 

[SHOZ123]

No I don't think it's something in the tune. Have you changed the tune? Put it back to stock if you think there is a problem with the tune and compare. Better I send a stock file so you can load that in. That won't affect the Xcals status.

The DTC specifically states this is an electrical or electrical support problem.

 

[bacernate]

Yeah I figured it was an electrical issue as the light appeared as soon as the car was started, and I restarted it a couple times to no avail.
We're pretty slow at work so I'll break out the voltmeter tomorrow and see what I can find.
Can this solenoid affect tcc operation when the od light isn't flashing?
Because I've had tcc problems for the last 10 months or so.
I flushed the fluid with 16 quarts of schaefers synthetic fluid 2 months ago and it's been pretty good since.

 

[SHOZ123]

The Electronic Pressure Control solenoid does what it says. Your TCC issues could be related, there is a chance the EPC solenoid is/was very weak and couldn't get the pressure high enough to keep the TC locked.

You can data log the EPC pressure, this is only commanded pressure though. To see the actual pressure you need to attach a pressure gage to the EPC test port. Yo can also data log the TCC solenoid duty cycle. And the actual slip when the TCC is applied. The last is the only real world actually happening value.

 

[bacernate]

I'm gonna just replace the epc and tcc solenoid this week. The car has been fine the last 2 days. 2 or 3 quick flashes in the morning on the way to work. Drives ok and I can't find any wiring problems unless it's the internal harness.
Is the side pan gasket reusable like the pan gasket?
I'm probably gonna have to order this stuff online or bend over and see if the local ford stealer has them.
Also Paul the tc you told me about before from monster trans, was that a higher stall than stock?

 

[SHOZ123]

Stall is based on engine output. When I first got the new TC and a rough tune with the new block and tranny it would brake stall at 2300. Now it will brake stall at +2500.

 

[bacernate]

Got to work on the beast yesterday, as we were very slow at work.
Replaced the epc solenoid and all seems well again. It ohmed out at 9.6 spec is 3.25-5. The new one ohmed out at 4.2. So I'm hoping and praying.
King of a pita to get the side cover out of the car, broken the fu%&*ng mlp sensor so there was another 90 bucks down the drain, but such is life in my world.

 

[wymjym]

Got to work on the beast yesterday, as we were very slow at work.
Replaced the epc solenoid and all seems well again. It ohmed out at 9.6 spec is 3.25-5. The new one ohmed out at 4.2. So I'm hoping and praying.
King of a pita to get the side cover out of the car, broken the fu%&*ng mlp sensor so there was another 90 bucks down the drain, but such is life in my world.

did you also replace the tcc one?
wj

 

[bacernate]

Yes I put a tcc solenoid in although it ohmed the same as the new one. Haven't put enough miles on it to give a definate answer but it does seem better.
I'll try to run it down the interstate tomorrow to see if I get lockup above 65 mph.
Not sure why I had problems above 65 but under that with the tune the tcc worked flawlessly, above that it was hit or miss.