Did you have to drill out the old sensor? I had a similar issue (trifeca and air gap) on my older 5 Series. It turned out that in drilling out the old sensor I had scratched the surface of the wheel bearing/reluctor ring. A tiny almost unnoticeable scratch, but that was the cause. The cure was a new wheel bearing. I have also read, of others "adjusting the air gap" by inserting thin washers to raise the sensor. That may be worth a try before opening your wallet to more abuse.

What suspension errors are you getting?

I also just went through a hellish problem on my HHCII - Error 116. I also rebuilt my compressor, using the www.bagpipingandy.com kit. I had to order a new cylinder bore and clock springs etc as well as the piston ring kit. My Compressor drier was all rusted up inside the drier can that is attached to the motor. When I took it apart there is a 'pepper pot' filter plate that had rusted up restricting air flow. Andy does supply a full kit that includes all these parts. Once I did this my suspension re-set and re-calibrated itself AFTER I cleared the error 116 using inpa. Some three weeks on and it has not returned..