ECUHELP KT200II ECU Programmer is confirmed to read/write dcm3.7 vag 1.2 tdi via obd.
Seeing is believing, please have a look at the following 2 images of using KT200II to write dcm3.7 via OBD.
And one more video about ECUHELP KT200 Read Write DCM3.7 and off DPF