The best bet for everyone here is to go to the dealer, or better, a local shop that has the European scan tool.

It turns out that all this fuss on my car was caused by the $110 left rear wheel sensor. That's it. I thought it was the ABS module, wasn't. I thought it might be the harness. It wasn't. Thinking got me nowhere, just bring it to someone with the European/BMW scan tool and be done with it.