Just got back from a 650 mile tow (first tow with truck, see post "08 F250 First Tow") and truck threw U0101 code on the way back. I had just refueled and gotten back on the interstate and noticed the check engine light was on. I was monitoring truck vitals with Torque Pro on my phone so I read the code. My wife googled it and came up with:

U0101 Lost Communication With Transmission Control Module (TCM)

The whole trip I thought my trailer brakes were grabbing when I applied the brakes while exiting the interstate on the exit ramp, but after getting the code I decided maybe it was hard downshifts. I was using tow/haul mode and decided to disengage tow/haul mode. After disengaging tow/haul mode, the hard downshifts went away. I guess I had never read what tow/haul mode was, but after reading the following from the owners manual, I think the hard downshifts was really engine braking.

Tow/Haul also provides engine braking in all forward gears when the
transmission is in the D (Overdrive) position; this engine braking will
slow the vehicle and assist the driver in controlling the vehicle when
descending a grade. Depending on driving conditions and load
conditions, the transmission may downshift, slow the vehicle and control
the vehicle speed when descending a hill, without the accelerator pedal
being pressed. The amount of downshift braking provided will vary based upon the amount the brake pedal is depressed.

After the U0101 code, my cruise control would not work. I used torque pro to clear the code, but cruise control still would not work. I stopped and restarted the engine and cruise control started working.

The truck ran great and only threw the code once. I was initially worried the hard downshifts were related to the code, but I believe that was really engine braking (especially since it stopped after I disengaged tow/haul mode).

Anyone have any thoughts on the U0101 code? Something to worry about??

 

It's computers...sometimes they don't talk right to each other. Clearing the code, then restarting to use cruise control is normal as well.

Tow/haul does a couple of things. First it holds the gears longer so you don't have excessive shifting.

Secondly it downshifts to provide a bit of engine braking...and holds the torgue converter locked longer.

Normal operation.

Sounds like a good trip overall.

 

have you experienced a no crank situation yet?

this is what i found on that code

<table class="ADVV1-HotlineArchives-Whites" cellpadding="0" cellspacing="0"><tbody><tr><td class="ADVV1-HotlineArchives-LeftRuledRows">
</td> <td class="ADVV1-HotlineArchives-RuledRows"> 1. Note U0101 states the transmission control module (TCM), is not communicating, this will result in a no crank situation as the PCM needs the transmission range sensor data from the TCM in order to crank the engine.

2. Access the TCM, see the attached location.

3. Check the power and ground to the TCM, see the attached diagram for reference, if the power and ground are ok, but the TCM U0101 still comes back when the TCM is plugged in, unplug the transmission connector from the transmission and retest, if the TCM still won't communicate, suspect a failed TCM.

4. If there is no power to the TCM, access connector 1010, see the attached location of the connector. This connector is located just above the left strut tower, ensure this connector is not unplugged or damaged. Then check fuses 72 and 37 in the under hood fuse box, see the attached fuse box layout for reference.

</td></tr></tbody></table>

 

I have the same issue on my 2010 Expedition. You refer to a few attachments on this thread. I do not see them here. Could you possibly repost those attachments?

They would be very helpful

 

Did you ever get those attachments? I am dealing with the same issue on my 2008 f350. I am suspecting mine is a bad tcm.

 

can you send these attachments please.....