About 3 weeks ago I posted a couple of codes that I downloaded with my trusty Innova 3100. P1448 .... Catalyst flap bypass circuit. P1128 .... Upstream HO2S sensors swapped. I erased them in the hope that this was a transient occurence. Light came on today after 2 weeks and ~ 100 miles of routine driving. This fault has occured after having 2 new cats put on by the main dealer, and a new secondary air pump. Main dealer also said they had no record of those codes. Any ideas ... performance does not seem to be affected. Car is a '96 355 Spider. Regards, Pete ... another bit of general info ... I had the alternator rebuilt. When back on the car the generator light flickered very occasionally, but the battery remained charged. Apparently there are two types of Ferrari alternator ... one for injection, and one for carburettors, the latter of which has less 'wires'. They put the carburrated one on my car ... not the injection ... hence the flickering.