When does check engine light come on 2005 vibe?

The check engine light in a 2005 Pontiac Vibe can illuminate for various reasons, including issues with the engine, emissions system, or other critical components. Common triggers include a loose or damaged gas cap, faulty oxygen sensors, or issues with the ignition system. It's important to use an OBD-II scanner to retrieve the trouble codes, which can help diagnose the specific problem. If the light stays on, it's advisable to have the vehicle inspected by a professional mechanic.