99-00 ECU's are obd2b. obd stands for On Board Diagnostic, for ecu's only. engine don't have obd classifications.
acutally half way through 99 on all model civics except the SI was a or b just a refrence not important
are you sure about that? i could have sworn the ECU i used to pass smog was a 98 ex, which plugged into my 96 harness (obd2a).
Stupid question. What is the difference between obd2a and obd2b? Is obd2a the same thing as obd2 basic while obd2b is obd2 advanced?