Here is a summary of my attempts to get a decent OBD2 reader that will work with my X-Type:
Mangoose SDD – that enables diagnostics/programming. It does appear that the Mongoose will read all the ECU fault codes but it is dependent on the software that you have access to.
I only wanted to read error codes, not reprogram anything. It came with TIS software and drivers. I installed it and it *works* exactly the same as my much more expensive mongoose. It has a full version of TIS, no license required. I reprogrammed a couple of options – works great.
ELM-327 v1.5 – another laptop solution, plenty of free software out there. Despite at least one other on this forum who said they use it, I just could not get it to work with my X-Type. I tried various of software.
Vgate Scan VS550 – a handheld code reader and live engine data readout. With my X-Type, I had to keep quickly switching off the ignition and then back on again, to make the menu structure move forward to the next menu selection. It was as if the reader was expecting some sort of handshake signal before it would progress. Once I was into the menu selection I wanted, it worked great. However it is a pain to get there. However, it works perfectly with the Wife’s Focus. I guess it hasn’t got the Jag protocol spot on.