If the codes are for the cats, you need to do the defouler trick, google it. Here in PA you fail for the light, cars with obd1, 95 and older get a tailpipe sniffer, but an MIL/CEL automatically fails(with one exception), obd2 plugs into the state emissions computer, if the ecu parameters are with in spec, you pass, MIL fails. That is only in certain counties, other like mine, are visual emissions, so test pipes fail, unless you know the inspector
, but NO plug in. Philly does a dyno + sniffer, ouch. get defoulers.