That is what I get too, what do you get for 621?

I get,

KOEO 621 X Shift solenoid #1 circuit failure

From both FFI site and my Innova 3145 book.

It is a "Key On Engine Off" test result, driving it/test driving it before it passes that test is....... well..... a waste of time. If it fails that test in anyway it will fail during normal operation.

As stated check that circuit from computer to solenoid pack for damage/corroded connections. Test it for continuity, wiggle the harness around while doing so looking for failed or intermittent connection.

 

I wonder where they get that as they copy information out of the Ford manuals and none of them say that.
It would not be a circuit failure if the solenoid will not drop out and going to third is an off or open circuit.
So the 621 definition does not hold up that those sites are giving you.
That is why I all ways go by the shop manuals and not the codes definition on the internet.
I also have the Innova 3145 book and I have found a lot of their definitions wrong also.

 

DTCs 621, 622, 626, 629, 641 and 652 indicate solenoid did not change state when requested by the Powertrain Control Module (PCM).

Odd yes, even an generic/basic google search for "eec code 621" brings up the same thing, solenoid #1.

Pretty much stating the same thing, just not stipulating as to which solenoid is the problem, so yea based on them all getting it right from Ford motors, how'd they determined it was #1???

I also agree, while a solenoid can get sticky its far more likely to be a electrical connection problem with these trucks.

 

I just checked through all of the FORD Truck shop manuals from 1992 to 1997 and not one of then say solenoid #1 for the 621 code.

 

It would not be a circuit failure if the solenoid will not drop out and going to third is an off or open circuit.

Your chart shows it is off so no it wouldn't, unless the circuit is grounding out someplace along the way intermittently, leaving the computer no control over its function.

However I'm not 100% sure solenoid #1 held "energized", computer thinking its not, would prevent the shift to drive, but I'd be apt to think it probably would.

 

it only shifts decently when NOT in overdrive, gets to about 40 and dumps to N. Past 35 or so, with the "OD Off" button pressed, letting off the throttle causes it to go straight to N, but it picks back up at the proper RPM and gear right where it left off.

This kinda suggests a PSOM issue, my 94 acted very similar but while shift lever was in OD. I'd take off from a stop light for example, it shift fine until it try and hit drive, be nothing there like neutral. Let off the gas and back on it be fine again, replaced the PSOM and the problem was corrected. Was an intermittent issue however it would now and then upshift rapidly into OD, do so in say 100 yards real quick and well before ever hitting the 45mph mark.

PSOM = Programmable Speedometer/Odometer Module

I do know one little electrical issue with these trucks can and will create a snowball effect real easy.

And subford no not disputing what you state, not at all. I have no idea where they get that "added" info for the codes. I always assumed they all got that data right from Ford and it would be exactly the same regardless of source.

 

OK it fails the KOEO electrical test.
So the computer is looking for voltage say from the #1 solenoid and does not get it.
Then it posted a #621 code, this could be a short to ground in the wiring to the computer from the transmission or an open in the solenoid coil.
I do not think the computer could test for a stuck solenoid valve.
It looks like the #1 solenoid is always on.
So I would guess that the wire from the transmission to the computer is shorted to ground as danr1 said above.

As far as the the 621 definition goes I think maybe when the E4OD came out the 621 did mean solenoid #1 and all the sites picked up on that.
Then Ford came out with the AODE/4R70W and 621 no longer meant solenoid #1 in that transmission so they drop it in the Shop manuals (I do not have a copy of the 1990-1991 manuals).
But the sites still use it to mean solenoid #1 and it would for the E4OD.

 

He should have goten an PSOM error if it was the PSOM.

 

He should have goten an PSOM error if it was the PSOM.

True and I feel I should have to, never once did though, it would pass all tests each and every time I checked.
My speedo needle was rock solid as well, that and no codes made it a real pain to narrow down the problem.

Yup it throwing a trouble code for the PSOM, that would have been to easy!

 

Well, that statement could not have been more true.

I decided to check the wiring and plugs from easiest to hardest. Chased the wiring back to the engine compartment...where they reach another wiring harness/plug...located directly beneath the brake master cylinder.

On said master cylinder there is an electrical plug in front of the resevoir (cruise control????? I'm not sure) which was slowly leaking...not enough to cause brake problems, but enough to screw up the tranny wiring. Opened it up, cleaned it out, re-greased it, and took a test drive in a truck that shifted almost like new!!!

So I guess you could say that a brake system leak caused my transmission to act up....new one for me...

Thanks for all the help...Probably saved me hundreds....if not thousands of dollars. Minus the $5 I spent on Advil from the headache this gave me, that is...

 

That leaking pressure switch on the MC can burn you truck up.
Take it to a Ford dealer and get a Free replacement and the recall done.
Keep your battery disconnected until you get it to Ford!

 

On said master cylinder there is an electrical plug in front of the resevoir (cruise control????? I'm not sure) which was slowly leaking...not enough to cause brake problems, but enough to screw up the tranny wiring.

Leave that unplugged, there is a recall on that and it can start the truck on fire, key "Off" no one in it at the time.

You can or should be able to get it repaired at no cost with a fuse put in, I got a recall on both mine.
I just unplugged em both I don't use cruise anyway, so its just not worth the time.

 

thanks...Ford part only? I need to take the truck to work tomorrow, so I will figure a way to cut off the leak and stay safe..

thanks again for all the help...if you ever need info on anything to do with bowling or residential remodeling, lemme know. Those are my specialties (obviously not an auto mechanic...lol)

 

mine's unplugged...still leaks...so that's why cruise wont work...I'm learning all kinds of stuff today...

 

Run the KOEO test again, I doubt that was your main problem, part of it? not sure at the moment. I'd have to review the diagram again to get a better idea.

It may be you simply moved the wires around enough to change things, but didn't "fix" it.

It will likely rear its ugly head again when you least expect it if not.