As from the pinout https://mk4-wiki.denkdose.de/artikel/abs/abs_pinout you connect pin 1 (YE-RD), pin 7 (GN-RD), pin 25 (RD), pin 33 (GY) to +12V and pin 40 to GND. Then pin 5+6 to HS-CAN of tester (e.g. UCDS) and you find the ABS module in lookup and can update it.
I wonder if the update would remove any calibration stored in the ABS oder security codes for PATS. But if i want to have it clean like a new one, how could i remove anything stored inside?