General Information

On Board Diagnostic (OBD), technical data
ABS control module -J104-
The part numbers listed here are used in production. The part numbers may vary for replacement parts however.
VAG1551 Scan Tool (ST) indicates control module identification during DTC memory check, e.g.

DTC memory
DTC memory contents remain intact even without voltage supply.

Data output occurs in operating mode 1 (rapid data transfer)

Safety precautions and troubleshooting basics
General information for troubleshooting

Notes:
^ ABS is a vehicle safety system; specific system knowledge is absolutely necessary for working on the system.
^ Before working on the ABS system, Check DTC Memory to determine existing malfunctions and to perform guided troubleshooting.
^ Make sure ignition is switched off before disconnecting harness connectors.
^ Do not drive with connector disconnected from ABS control module.
^ Malfunctions in the ABS system are indicated by illumination of the ABS warning light. Certain malfunctions cannot be recognized until vehicle is driven for 30 seconds above the minimum speed of 60 km/h are reached (road test vehicle).

Notes:
^ If the ABS warning light -K47- and the warning light for brake system -K118- are not lit, but the brake system is not functioning properly, check for malfunctions in the mechanical/hydraulic part of the brake system.