We have an '03 Honda Civic Hybrid, and I got a OBC code that indicated a problem with the catalytic convertor... after resetting, it came back about 3 month later. Everyone wanted over a $1000 to fix it, and since there are two convertors, I didn't want to screw with it myself. A buddy with connections to the auto repair business suggested running Sea Foam thru the fuel system, and when we did, the light stayed off. Turns out Honda had a recall to recalibrate the computer to correct for overly sensitive ox. sensors that were falsely indicating that problem. The Sea Foam cleaned up the sensors, I believe. Anyay, after the recall, all is well, and I am only out the Sea Foam's $8.