I/M Test Preparation

Before having your vehicle tested, plan to perform recommended preventative maintenance. If the on-board diagnostics (OBD) check engine light is on, the PCM detects an emission system component or engine issue and the vehicle is guaranteed not to pass testing. Never cut off emission components like the catalytic converter – it is illegal and will cause emission test failure. Vehicles are designed to run properly with emission components and will emit large amounts of pollution if any of these components are disconnected or removed.