Monitored Emission Control Systems

The OBD II System monitors all emission control systems that are on-board. Not all vehicles have a full complement of emission control systems. For example, a vehicle may not be equipped with secondary air injection (AIR) or exhaust gas recirculation (EGR). The OBD II regulations require monitoring of the following:

• The air conditioning system
• Catalytic converter efficiency
• Comprehensive component monitoring - Emission related inputs and outputs
• The evaporative emissions (EVAP) system
• The EGR system
• The fuel delivery system
• Heated catalyst monitoring
• Misfire monitoring
• The oxygen sensor system (O2S or HO2S)
• The oxygen sensor heater system (HO2S heater)
• The AIR system

For the specific DTCs required for each system, refer to Inspection/Maintenance (I/M) System DTC Table . Systems such as fuel delivery, misfire, and comprehensive components may not be listed in a system status list. These tests run continuously and do not require an I/M System Status indicator.