No, it isn't a science fiction story... I'm writing from Orlando, FL, site of the Technology & Maintenance Council (TMC) Annual Meeting and Expo, and the warning from the future came in the form of a technical session entitled "EPA's 2010 Heavy-Duty Diesel On-Board Diagnostic (OBD) Requirements Present Challenges to Manufacturers and Fleets." As you know, a new round of heavy-duty diesel emissions standards will hit again in 2010, and the new emissions systems will be accompanied by an on-board diagnostic system, to make sure that those engines are running clean day in and day out. Because OBD and OBD-II have been around in the light-duty market for so long, the heavy-duty market can learn from the LD experience... The problem is, a lot of that experience has been bad. For starters, because of the new OBD systems, the 2010 engines will be throwing a lot more fault codes (now known as diagnostic trouble codes, or DTCs). The make matters worse, many of those new DTCs will be "symptomless." In other words, the driver is never going to notice a thing. The DTCs will only report conditions, not root causes. The rest will be up to your technicians. But, as one of the experts on the panel said, "It will be more difficult for technicians to find the cause of a fault." One fleet maintenance manager in attendance had a shorter explanation: "It's going to be a nightmare." Welcome to the future.