Monitored Emission Control Systems

WARNING: This page does not describe the selected car, but rather 13 other vehicles, including the 2002 GMC Yukon XL, 2002 GMC Sierra, 2002 GMC Savana Special, 2002 GMC Savana Camper Special, and 2002 GMC Savana. However, it is still accessible from the selected car via links, so may be relevant.

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:

Air conditioning system.
Catalytic converter efficiency.
Comprehensive component monitoring. Emission related inputs and outputs.
Evaporative (EVAP) emissions system.
Exhaust Gas Recirculation (EGR) system.
Fuel delivery system.
Heated catalyst monitoring.
Misfire monitoring.
Oxygen sensor system (O2S or HO2S).
Oxygen sensor heater system (HO2S heater).
Secondary Air Injection (AIR) system.

For the specific DTCs required for each system, see INSPECTION/MAINTENANCE SYSTEM DTCS table. Systems such as fuel delivery, misfire, and comprehensive components may not be listed in a system status list. These tests run continuously on some vehicles and may not require an indicator.