That's what nano says.
Back story...
Book symbol up, nano says pot fault on rh blend motor. Replaced the pot on that yesterday, horrible job. That fault has now gone but a new one has popped up as per title. I should say that I removed the DISTRIBUTION motor first for a look see inside to check for wear, bad joints etc then put it back together making sure the gear arrows were enligned, then refitted it insuring that the flats were mated correctly. Then I removed and repaired the BLEND motor pot.
Refitted it all, plugged in the hvac and clocks but not the radio or upper console with the time clock in and read the nano. Pot fault on the blend is gone but I now have the title fault that won't clear on the DISTRIBUTION motor.
I've taken the distribution motor off again and opened it up, can't see anything wrong, enligned the gears again and refitted to the box, observing the flats locations(again). Flaps move freely and , indeed, I can see the box gear wheels moving through their full movement, air changes direction as expected, recalibrated a few times, fault won't clear, book up.
I have noticed, might be relevant, that if I turn the ignition off then on again the book has gone whilst the hvac motors are whirring away for maybe 15 seconds (self test?) Then the book comes back as soon as the motor(s) stop.
TIA.
Chris.

Yes, the 15 seconds will be the self test where it drives all of them from one end of the travel to the other to check for feedback. I've been fooled by weird errors at times so look at the inputs, values and see what the distribution motor feedback is showing, then try poking the Prog button and see if it changes.

Cheers Richard, quite new to p38s and never had a diagnosis reader before, so new to nano too.
Rubbish on computers too just to add to my woes hahaha 😆.
Only got a smart phone.
I'll have another play tomorrow. I did look at values/inputs and did see things that didn't look 'right' but that was on the rh blend motor and nano says that's got no faults.

Yes, if you look at the input values it will show you the feedback from each blend motor (and the blowers). So you look at the figure it shows and then change the temperature to HI on both sides, the numbers should increase. Then set both sides to LO and they should decrease. You can use the manual blower speed control to change the blower speed and you should also see the feedback from them changing. Distribution motor is the only one that is a bit hit and miss as you can use the Prog button to send air to the screen and use the other air distribution buttons to move it. I say it is a bit hit and miss as it doesn't really follow any set pattern like the others, it just wanders around depending on where you want the air. Really, all you are looking for is changes.

Fixed! (I hope..)
Googling about I found a few posts, one of which was yours on rr.net about unplugging the motors at the hvac panel and plugging back in. I first read the nano and the distribution stall fault was still there and wouldn't clear, then I did the unplug/plug thing then ran through all the values and the values were all changing on all three which the rh blend wasn't doing yesterday.
Book symbol gone, no faults on nano.
Turned the ignition on and off and still no book.
Glad I tried the unplug/plug thing first so thanks!
Hope I haven't spoke to soon.
Taking the steering wheel off next, battery disconnected while I have lunch, and stripping that down to release all the buttons so I can redo the decals, another first for me.