The good news is the service engine soon light is now off; and on its own... meaning whatever was causing the light to turn on has not been recently detected (or corrected itself) by the engine control computer. The question is, are the "emission monitors" ready for the smog test? Having had the service engine soon light on meant there was a trouble code(s) stored in the computer. With any trouble code(s) in the system, the computer may have not been able to complete one or more emission monitors. Emission monitors are internal self-tests which the computer performs to ensure the engine is running efficiently and not polluting. The best way to know if the monitors are ready is by using a OBD-II scan tool to run a system check. You may visit a smog check station and explain to them that you recently had the engine service light on and that it turned off by itself. They will want to make sure the monitors are complete before they administer the smog inspection. So... although the service engine soon light is now off does not guarantee a passing smog test. The emission monitors must also be complete. There is no dash light to indicate the readiness status of the monitors, as such, a scan tool must be used. If any monitor (with the exception of the EVAP) is not ready or complete, your Pontiac Grand Am must be driven through a Drive Cycle. You may either follow the drive cycle specifically designed for the Pontiac Grand Am or you may simply drive your car for about 200 miles over the course of a few days and in both city and highway traffic in order to trigger the drive cycle and complete the monitors on their own.
posted by SmogTips Support
