The thing is, even the official dealer in my country doesn't give me any information. I have completed courses and certificates for service activities and handling computer diagnostics and believe me, not everyone can handle it, you need to understand what exactly you are doing. Calibrations, ignition corrections, entering injector codes, programming computers and many other options are done. That's why I think that only trained personnel should handle it (my opinion). And modern tractors are self-diagnosed via the CAN bus so that if there is a real problem, they display an error code on the dashboard, which can orient the operator where exactly the problem is and try to fix it.