"..My guess is the ETM is broken or the connector to it is bad...."

That goofy little connector at the ETM was suspect when I was going through this. Have you taken a good at it to see if the wires are still firmly terminated within the connector or that the contacts haven't gotten pushed back, etc? Not knowing exactly how to unlock the connector from the ETM, I finally ended up snapping off both locking tabs. It's now held in with a zip tie to make sure it says firmly engaged with the ETM. Even my indy tells me that's not at all uncommon. He also said that stretch of harness from the ETM to the ECM (with new connector already attached) can be purchased separately from Volvo if yours is at all questionable.

Are you sure it was the ECM you R2'd and not the TCM? Or maybe you reseated both while you were at it?? Did you unplug and replug it in a few times, using some sort of contact cleaner, to make sure the pins were scraped clean?

If the problem continues to point to the TCM, I've got a spare one that I'm pretty well convinced is still good if you need to borrow it for a week or two as a test. You just pay postage back and forth and promise to return it :)
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Current rides: 2005 Volvo S80 2.5T, 2003 Volvo V70 2.4NA, 1973 Volvo 1800ES (getting ever closer to road worthiness)