I have an ODB2-Bluetooth-Adapter(link) to access the ODB-Protocol with my android-smartphone.

It is basically working. The app that I use ("Torque") can connect to the ECU, shows me different values like temperature, speed, pressure, load, and so on. I can also access the engine-control-unit of my car (2009 VW Polo 6r 1,4) and access it's fault codes.

However I have a problem with the ABS-control-unit. I got several warning lights in the dashboard, which are all related to the ABS (ESP, Tire-Pressure, and ABS). Now I wanted to use the app to show me what exactly is wrong (probably just a faulty sensor), but the app cannot access this ABS-control-unit. It can only find the engine-control-unit. I also tried a different app ("Scan Master Light"). This app lists all the available control-units of the car, but it only lists the one of the engine.

Where is the problem here? Is the adapter that I use not capabable of accessing other control-units than the engine? Or is it the application on the android? If so, do you know another application where I can actually read the fault-codes of the ABS?