As most of us know (or have found out..), the rear calipers on our cars have a hex socket bolt that holds the inner piston for the emergency brake. Without releasing that bolt, the piston will not retract.

Was placing the rear rotors and pads on my 2011 VW Tiguan today and the piston would not move. Saw there was a motor assembly mounted on the caliper. Apparently it functions just like the 914 ones; a motor locks the piston in place for the electronic handbrake.

First internet search said you needed a computer hookup to energize the motor and retract. Sorry, not doing that... Next one had a clever bloke who figured out you just need to put 12v across the terminals; depending on polarity, the motor moves in or out.
Solved my problem in under a minute Seems these kind of calipers are common on VW, Audi, Mecedes, (newer Porsches?).

On the Mercedes you get into a maintenance menu on the display by pressing or holding buttons in a specific pattern. I’d bet the VW has a similar secret menu. Recently repalaced the rear pads on the wife’s GLE, dealer wanted $800, I did it myself for about $150 (parts)and an hr of my time.