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Discussion Starter · #1 ·
I have looked through the threads and can not find one specific to my issue.

MAy be too old and a long shot. I have a 2003 Excursion 6.0L with 5R110w. I bought it with the tow haul blinking and in 3rd gear limp mode. The owner has money so he just parked it, bought and new truck and said come get it for x$$. He stated the OD and 4 solenoids were out according to the tranny shop and he didn't want to put money in it. I pulled the pan, changed ALL solenoids, internal harness, dummy plugged the controllers, changed the temp switch, fluids and filters.

Still have tow haul. Codes were pulled and all was for fan, ICP and one injector. Replaced all that. I traced the wires visually when cab was off getting bullet proofed because I figured one of the top sensors was bad (did not do continuity test for lack of garage time) but DID change all tranny upper and rear sensors.

Still have light blinking and in limp mode 3rd gear. Took to 2 tranny shops. They can not pin point an issue and say the tranny is strong other than in limp. They are not trained in these or diesels at all. Side note, I am not against replacing the tranny, but I do not want to replace it and still get a flashing light..............LOL. Please help, Any help is greatly appreciated.
 

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With a flashing light, you have a code. many code readers will not thoroughly read transmission codes. So we need to know what code reader is being used.

ForScan Lite downloaded to a smartphone will ($6). Then you need an OBDII adapter for yur specific device (apprx $40). I like the value of the BAFX brand adapters - they work well.

If something is pulling down the 12V "reference" voltage, it can cause problems similar to what you describe. That said, it is ONLY a guess since we have no specific information (other than it being said to be in "limp mode").

BTW - a short in the fan clutch and or its wiring can pull down this 12V circuit voltage, so if there is a fan clutch code, why not go ahead and fix that?
 

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Discussion Starter · #3 ·
Thank you Bismic, I will look into the scan tool.
I believe the tranny shop had the Mac tool one but not sure.

I replaced the fan hub and chased the wires to the main harness, and it was all good. That code reset based on the small scan tool I used which you are correct, it does not pull tranny codes or in-depth system codes, only major category codes.

I have not fully completed continuity testing on all harnesses because of time restrictions, I really do not know where to start without guidance from the vast knowledge on here and honestly lack of DC electrical knowledge.
 

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While there are a few other 12V "reference" circuits for several actuators/valves, they usually do not have the wire size to pull down the voltage like the fan clutch does.

I would start verifying the wires between the PCM and the transmission if you haven't done so already.

.... and get ForScan!

WiFi adapter for iOs and Blue tooth for Android. USB OBDLink adapter for a windows laptop.
 

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Discussion Starter · #5 ·
Thank you again for the response. I have downloaded the App and ordering the adaptor shortly. I am not able to find the OND2 adaptor you referenced but did find a OBD2 on amazon. Is it the same?

I did visually trace the PCM connector harness to the tranny, but got ran out of the shop and cab was lowered before I could strip the harness in full and do the continuity check. Again, Novice here, I am not sure how to do that whether it be by ohms, battery test drop etc. I certainly do not want to apply voltage and fry something else. AS I said I am not up on DC circuits and troubleshooting. Is there a tutorial link you may know of? A diagram link I haven't found etc? I have found general tutorials but nothing that may help with my specific harnesses as far as what wire controls what. I guess that comes with experience like on these forums.

AS A NOTE< I REALLY APPRECIATE YOUR INPUT!!
I have been looking for months honestly to try and find stuff myself and finally gave up and started looking for better help like this. The truck was purchased in Nov 2020 and December 2021 my amazing wife said it had to be fixed or moved out of our driveway because we have a new grand baby coming and visitors to the house have increased. That usually means move it or it will be gone the next week. LOL.
 

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SORRY!!!

A typo. The "N" and "B" are too close together, lol.

It is in fact OBDII!
 

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I don't have a wiring diagram manual for your year model - sorry!

Maybe they could be found on-line.

I would just start with a continuity check (ohms of resistance would work) between the PCM and the transmission.

C1381b (PCM connector for most transmission wires) is the plug closest to the vehicle front.
 

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There are 3 connectors at the transmission:
C1385 (the 24 pin connector)
C1387 (for the turbine shaft speed sensor and the intermediate shaft speed sensor)
C1107 (for the output shaft speed sensor)
 

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This file has the wiring diagram for the 24 pin C1385 connector:
 

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Discussion Starter · #12 ·
Bismic, awesome information. I'll do further research with what you've set thus far over the next few days or so and report back. This is very much appreciated.
 

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Discussion Starter · #13 ·
This file has the wiring diagram for the 24 pin C1385 connector:
So I pulled the only code it had stored. P0765
What I have already done before pulling the code back in November is all Tranny Solenoids were changed, internal harness changed, temp sensor changed and all external harnesses visually checked, all tranny and rear sensors changed.
 

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My resource says that is a Solenoid "D" circuit code.


That said - there appear to be mechanical issues that would also cause it:

blocked fluid passageways
internal transmission failure

Based on earlier posts, I would think that the fluid is clean and is an approved fluid. Hopefully you used OEM electronic parts. I don't have a great trust in the aftermarket electronics.

 

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Discussion Starter · #15 ·
OEM solenoids and internal harness yes.
Any idea on the pin number or color for the D solenoid? It is violet/orange on the 07 sheet you graciously sent last week.
I have yet to find the specific one in the other data sent nor the data I have found in forums and boards. What confuses me, is D not only controls 1-2, it controls reverse also. Reverse is fine. Before the swap out, it wouldn't even shift out of 3rd. Now it does.
 

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My 2006 transmission wiring diagram shows SSPC-D to be the "Black with Light Green Stripe" wire. Pin #4 of connector C1385. I will have to look closer at the 2003 diagrams I sent you - I am not all that familiar with that year.

SSPC-D and SSPC-A are controlled by an "inversely proportional" solenoid. The others are directly proportional. Solenoids A and D are the same part for both, but they are different than the others.
 

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Discussion Starter · #17 ·
I placed them all as directed by Ford and made sure all the "slots" lined up and fit correctly. I also tested each to make sure they were within operational range. Not sure the spec that was a year ago.

This weekend I hope to crawl back under, pull the harness and check the pins and continuity. Again. Last thing I want to do is spend another $4000 and still have a little blinking light and 3rd gear. LOL

Is it possible the TCM could be shot and if so, how can I check that without replacing it for $800 first?
 

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The TCM and the ECM are all internal to the PCM. Can you get a new PCM for $800? Where were you looking for that?

I truly doubt that that is your issue.

I would lean more to blocked fluid passageways if you don't find a wiring issue.
 

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Discussion Starter · #19 ·
Sooooo Mark, the pr now solved. Due in whole and in part by your help and links. I did a continuity check finally on all the harness circuits. All were good but the specific on for slot 4 and 20 in the harness for my Exc.

The wire it controlled is indeed the D solenoid. So I ran a splice wire externally to the harness plug and just like that, continuity. I also checked to make sure it was not grounding out on the truck or into another wire. It wasn’t.

So I made a stable splice to patch in externally. AND I decided to move forward with stripping the harness to find an issue if I could. Because my anal/ocd aircraft mechanic self won’t let it go and where there is one issue, there may be another. Just 6 inches from the lower plug I find a wire that was slightly pinched in the loom and taped over the first visual done. Pulled it to straighten it out and snap, pulled right apart with my thumb nail. Stripped it back and it had been arcing in the casing for apparently a long time. Both ends were about 1/8 inch apart and completely grey 1/4 inch in its been arcing for so long. I spliced, soldered, heat shrinked and wrapped that one back up too, “just in case” the external fails.

The tranny was relearned and is driving strong so far. Your assistance has been amazing and very appreciated. I recommend that others heed your advice and not wait over a year to ask like me….lol. Thank you again sir!!!!!!
 

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Glad you resolved it.
 
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