VAG Blocks is beta open source (GPLv3) software for reading VAG group specific measuring blocks from an OBD-II port using an inexpensive ELM327 type adapter. Both Bluetooth and USB adapters have been tested on Windows & Linux. Sample rates of up to 12 samples per second have been achieved.
Various control modules are supported such as the engine ECU and gearbox. Values such as boost, oil temperature, DPF soot loading and current gear can be plotted in program and logged to a CSV file.
You will need a label file for each module to determine what the values mean. Without a label file VAG Blocks will only tell you the units of the parameter eg. You might see a value of 80 °C but without a label file you cannot determine if it is the oil temperature or the coolant temperature. Plain text VCDS/VAG-COM style label files and redirect files are supported by VAG Blocks.
Currently the communication protocol is unstable and the software is still in beta phase. The ELM327 is designed for reading OBD-II PIDs and its raw CAN mode is limited which makes implementing VW TP 2.0 difficult.
For more information please see http://jazdw.net/vag-blocks/