- Loose gas cap: The most common reason is a loose or missing gas cap. When you refuel your vehicle, the gas cap forms a seal to keep fuel vapors from escaping. If it's not properly tightened, it can cause the check engine light to come on.
- Faulty evaporative emissions system: The evaporative emissions system prevents gas vapors from being released into the atmosphere. It has several components such as the gas cap, fuel tank, fuel lines, and charcoal canister. If any of these components fail or are damaged, the check engine light may come on.
- Oxygen sensor issue: Oxygen sensors monitor the oxygen content in the exhaust gas to help ensure complete fuel combustion. If an oxygen sensor fails or becomes contaminated, it can cause the check engine light to come on.
- Fuel injector problem: Fuel injectors spray fuel into the engine's cylinders. If an injector fails or gets clogged, it can cause the engine to run lean, which can set off the check engine light.
- Catalytic converter issue: The catalytic converter is part of the exhaust system and helps to convert harmful pollutants into less harmful substances. If it becomes clogged or damaged, the check engine light may come on.
