I had this same issue with a Honda after disconnecting the battery to do some other repairs. In order to get the cat. readiness monitor to set, I had to drive the car at exactly 55 mph for 10 minutes. This was difficult to do, due to traffic conditions on the freeways, but it worked. Not sure if this would help with a 450 smart. I would do a google search or check the Evilution & FQ101 websites. Evilution requires a small subscription fee. Also, a smog technician or the referee should be able to tell you what the procedure is. I have heard that 50 key cycles should also reset the monitors.