Durametric Scan Tools for Tiptronic?

Hi All, In my ongoing saga of the odd shift patterns, a mystery remains. Background: Started experiencing shift flair when going into or out of 4th gear. Flushed the trans fluid, no change. A helpful tip from Porschetech3 suggested it could be the valve body. So off it went to have the valve body rebuilt. While in that shop, their tech found one of the pressure valves had been installed backwards, only getting 60% of the vacuum pressure I should see. Replace some valves, reinstall, drive the 150 miles back with no issues, and straight into storage it went (December last fall). I take it out in late Feb and now I'm seeing a similar issue between 2nd and 3rd, which it never did before. I call the valve shop, and they assure me it's fully covered, but when he learned it had been in storage the prior two months he suggested I try it again in the morning. He said it's possible that the battery got low and the CPU (?) lost some of its programming, and the fresh charge from driving it might get it to reset overnight. Next morning I drive it again, and sure enough, no more issues. Back to storage. A month later and the first day it's out is fine, no issues. Back to storage. April comes, no problem. May comes and after a couple weeks in storage I'm finding the same odd shift issues going into or out of 2nd. Assume it's the battery/CPU and the next day all is well again. But now that it's been my [near] daily drive, once it's warmed up, and only sometimes, maybe every third time out when I drive longer distances to really warm it up, it still has a vaguely similar issue to the prior 4th gear flare. But where the prior issue seemed to be a delayed shift (so the shift delayed and then the rpms never matched properly, and then it shifted hard), now when shifting from 2nd to 3rd it's as though it shifts too quickly, making a slight 'thunk' with the sudden shift (not as bad as it did last fall with the 4th gear flare). Downshifting from 3rd to 2nd isn't an issue. Shifting from 2nd to 3rd in higher revs (over 4k) doesn't seem to be an issue. Letting it shift in automatic is rarely an issue (where it wants to shift at 2000rpms unless I'm juicing it). So I call the shop, and he says it sounds as though the computer isn't sending reliable information or isn't reading my speed/rpms accurately to make a proper smooth shift. Suggests I get a Durametric scanning tool and use the OBD2 plug to see what's happening. So my questions for the brain trust here: Has anyone done this before? Does anyone know of any shops that deal with the CPU (I assume this is the computer/brain that runs the shifting) to get an idea what might be happening or what I might need to do to fix this? New CPU? Flashing the current CPU?

You car a .1 or .2?

.1 An early build '99.

So it appears the tiptronic controlling unit is a TCU. Has anyone done an upgrade to theirs?

There are upgrades for the .2 TCU. Not sure about the .1. You might check if the ABS is fouling things up. The TCU gets a lot of data from the ABS. You can unplug the ABS and see what happens. Beyond that I don't know much about the ZF auto box.

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I have my old TCU somewhere, pulled for a manual swap. Mines a C4S so not sure that makes a difference?

C4S is a .2 so would have a different TCU for the Mercedes auto box.

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ABS? I also just heard about a PIWIS, but I'm not sure what that is either. It does seem like a data thing as the only consistency is that it's a 2nd gear thing, and then only occasionally under different circumstances. This might be a dumb thought, but any chance simply disconnecting the battery for 10 minutes and hook it back up could reset whatever program decided to get squirrelly, like unplugging a computer for a hard reboot?

ABS = anti lock brakes, I was suggesting to pull out the fuses to disable the ABS and see what happens. I am not an expert on the ZF trans in the .1 cars though.

If it relates, I had the brakes and rotors replaced at the same time as the valve body, and I have noticed I have a dragging caliper on the front passenger side. It doesn't seem like a lot, but maybe after driving it creates just enough drag to throw off a sensor? As of now, the issue seems limited to only upshifts from 2nd to 3rd (feels like a rushed shift), both auto and tip mode, and only after being fully warmed up.

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Now this might be a coincidence, but... When I bought it the dash airbag light was always on. Mechanic said it was a bad seat belt wiring harness, replaced it. Light went away. On the long drive home I adjusted myself on the seat, and right as I did this the light came back on. I assumed this unplugged the wire harness that runs under the seat, and I've been meaning to remove the driver's seat and reconnect. Does anyone know if there's a TCU plug/wire run also under the driver's seat in a '99? Seems oddly coincidental.

The TCU is behind the passenger's door on the kick panel. The wiring to the shift **** goes up the center tunnel as I recall. So nothing under the seat.