I worked to connect ECU to my laptop few months ago, after all the research on the internet,
--- Managed to get software ( infact more than one ) for running on windows PC on OBDII standard. Infact even if we get the logs these are useful as well for troubleshooting and avoid messing up with mechanics.
--- Studied the port configuration of my car's ECU connector (Baleno)
--- Now the big issue was the connector between serial port of my computer and ECU. (Getting somewhat technical this connector isolate high voltages) Now this connector is very costly, searched on the net. At last get the circuit diagram to make this connector and stuck at this point if I can get this circuit implemented correctly it would be a very cheap solution.