Hi Tom, thanks for joining us, fairly sure I've driven through Aachen at some point
Do you get your MCU error when you are running on petrol, or just on autogas? Its not uncommon to get cat-diagnosis lambda errors when running on autogas, a friend with an opel had the same issues recently.
In general, you should use VCDS for diagnosis. Nefmoto is for reading/writing maps to your ecu, but in this case you probably want to disable the secondary lambda sensor in your ECU, so you would need to read the map from your ECU, edit it and write it back.
The only issue may be the chip tune you already have, as some tuners deliberately make it hard to read/write the tune, or try and hide the data in the map so you cannot edit it.
Your first step is to read the nefmoto getting started guide and read the map from your ecu, but please dont post it if it is a commercial tune.
