My 2008 Volkswagen Touran came with Parking Distance Control, beeping to indicate the remaining distance to objects when the car is in reverse gear. The control unit that I had was of an old type, and I had the impression it wasn't functioning 100%. So I got a new module from Kufatec, to replace the old one.
Kufatec explains that you need to run a wire from the back of the vehicle to the front, but as it turns out this is not necessary when the old module is already at address 10 on the CANBUS network. If the old module is at address 76, then you do need the new wiring. I already ran the wire to the front of the vehicle and connected it before realizing that I didn't need it. Result: countless electronics error messages in the on-board diagnostics. It could have been a simple drop-in replacement, if the documentation would have explained this correctly. Clearing all the error messages took quire some time, but was succesful in the end.
The new module works well now, and as a bonus, it gives me visual status of the four individual parking sensors (OPS) in addition to the beeps (regular PDC). This Youtube clip shows what it looks like after the upgrade.