1. Oxygen Sensor: A faulty oxygen sensor can cause the check engine light to come on. The oxygen sensor monitors the amount of oxygen in the exhaust gas and helps to regulate the fuel mixture. When the oxygen sensor fails, the engine may run rich or lean, causing emissions to increase and the check engine light to come on.
2. Catalytic Converter: A damaged or clogged catalytic converter can also cause the check engine light to come on. The catalytic converter is responsible for converting harmful pollutants in the exhaust gas into less harmful substances. When the catalytic converter fails, the check engine light will come on and the car may emit a foul odor.
3. Mass Air Flow Sensor: A faulty mass air flow sensor can cause the check engine light to come on. The mass air flow sensor measures the amount of air flowing into the engine. When the mass air flow sensor fails, the engine may run rough or stall and the check engine light will come on.
4. Faulty Spark Plugs: Worn or faulty spark plugs can cause the check engine light to come on. Spark plugs are responsible for igniting the fuel mixture in the engine. When spark plugs fail, the engine may run rough, stall, or have difficulty starting.
5. Vacuum Leaks: Vacuum leaks can also cause the check engine light to come on. Vacuum leaks can cause the engine to run lean, which can lead to increased emissions and the check engine light coming on.
6. Fuel Injector Issues: Faulty or clogged fuel injectors can cause the check engine light to come on. Fuel injectors are responsible for delivering fuel to the engine. When fuel injectors fail, the engine may run rough, stall, or have difficulty starting.
If the check engine light is on in your Volvo 850, it is important to have the vehicle inspected by a qualified mechanic to determine the cause and have the problem fixed.
