Your Chevy Cavalier's On-Board Diagnostic system (OBDII) is designed to monitor all aspects of your engine's emission conditions and report this information to a central database within it's computer.
If a decision has been made to alert the driver of an emissions problem, the "Check Engine" or "Engine Malfunction" light will illuminate on the vehicle's dashboard. Along with the "Check Engine" light being illuminated, there are stored computer codes in your Chevy's ECC (engine control computer) which the smog station will be able to retrieve and use for diagnosing purposes.
In order to learn which emission system(s) need repairs you must have the trouble codes. Our recommendation is having a certified smog repair shop conduct a complete hands-on diagnosis. The retrieved trouble codes will more then often direct a smog technician to finding the fault.