[Joshinator99]

Originally Posted by arpad_m

Writing either the ECM or the TCM takes a relatively long time (minutes), and you see a progress indicator during the process. Unless you specifically selected the Write Vehicle item or button and then saw this window, you didn't write anything into your TCM. In addition, you need credits for writing, so you can only physically write your car if your tuner used the same MPVI2 device, if you have your own, you'd need to buy credits for your unit first.

As Josh said, unlike the ECM, the T87A TCM module cannot be read. When one tries to read it, the process seems to succeed, but you end up with a stock TCM tune file, which is what the warning is about.

Therefore, I'd say it is essential that you obtain your actual tune file(s) from your tuner so that you have a reference "after tune" state that you can always write into the car, should you tweak the tune yourself, have someone else modify it or for some reason need a new module later etc.