What is the difference between obd1 and obd2?and what is obd?:uhoh:

On Board Diagnostics. OBD-I was implemented on 92-95 Civics's and OBD-II was on 96-00. It's basically the engine management system. OBD-I is simpler, but there are far more tuning possibilities on the market that support it. OBD-II has a more comprehensive engine monitoring and feedback system, but it is less favorable to after market tuners and far less supported.