There are a lot of possible causes for a vehicle to not pass an emissions test. The catalytic converters are just one of them. We have no way of knowing what diagnostic tests were done or what the results were. '96 and newer vehicles have the "on-board diagnostics, version 2", (OBD2) emissions system which includes downstream oxygen sensors to monitor the efficiency of the catalytic converter(s). There should have been a diagnostic fault code related to "catalytic converter efficiency", and since it affects emissions, that code will turn on the Check Engine light. If that code was not set, your mechanic will have to interpret other test results to determine if the converter is causing a problem.
Catalytic converters do not last forever. We read often about people having to replace them in less than 50,000 miles, and some are real expensive. We don't get involved with costs here because there's way too many variables. Dealers can install new ones from the manufacturer but most will try to save you money by installing an aftermarket or rebuilt converter. Some independent shops will only install new ones from the dealer because they may have had a bad experience with those from aftermarket suppliers. New ones from the manufacturer are designed to work with the engine you have. Many aftermarket converters can fit multiple applications and they aren't always fine tuned specifically to your truck. They can work but not good enough to pass an emissions test, and your mechanic may be hesitant to want to use one. The cost depends on which converter they want to install, the choices available to them, their hourly labor rate, which engine you have, and things like that.
Monday, September 23rd, 2013 AT 12:30 AM