Last winter while working in Upstate NY, the "emission system Problem" light came on. I checked it with a code reader, and it said the problem was low efficiency in bank II of the catalytic converter. That sounded expensive. I reset the alarm, but it came on again a week later. A friend said to run a couple of tanks of premium gas through it. I reset the alarm again, used 2 tanks of premium gas on my drive home to Florida, and no more warning light. One year later, up pops the warning light again. Again the code said catalytic converter bank II below minimum efficiency. The car has 75,000 miles, so the emissions system is still under warranty. I took it to my local Honda dealer, and the real problem was with the software. There was no problem with the cat converter or the sensors, but the program was evidently reading the sensors incorrectly. They reprogrammed the system, and no more problem. I imagine there is a service bulletin on this, but I hadn't seen it. I was imagining an expensive repair, but it was simple software error. I never had any emission system alarms on my 2003 Pilot, and I drove it 300,000 miles. I thought this might help other drivers who get this alarm and are freaked out by thinking they need a new catalytic converter.