* Oxygen sensor: The oxygen sensor measures the amount of oxygen in the exhaust gas and helps the engine control module (ECM) adjust the air-fuel mixture to maintain optimal performance and fuel efficiency. A faulty oxygen sensor can cause the ECM to receive incorrect information and adjust the air-fuel mixture incorrectly, which can lead to various engine problems and illuminate the check engine light.
* Catalytic converter: The catalytic converter helps convert harmful pollutants in the exhaust gas into less harmful substances. A damaged or clogged catalytic converter can reduce the efficiency of the exhaust system and cause the check engine light to come on.
* Evaporative emissions (EVAP) system: The EVAP system helps prevent fuel vapors from escaping into the atmosphere. A leak in the EVAP system can cause a decrease in fuel efficiency and potentially trigger the check engine light.
* Mass airflow sensor (MAF): The MAF sensor measures the amount of air entering the engine and helps the ECM calculate the correct amount of fuel to inject. A faulty MAF sensor can provide inaccurate readings to the ECM, causing the engine to run too rich or too lean and result in the illumination of the check engine light.
* Spark plugs and/or ignition coils: Worn spark plugs or faulty ignition coils can cause misfires, which can trigger the check engine light. Misfires can occur for a variety of reasons, including worn spark plugs, faulty ignition coils, or problems with the fuel system or engine timing.
* Engine timing: If the engine's timing is off, it can cause various problems, including rough idling, hesitation, and reduced engine performance. Incorrect engine timing can also potentially prompt the check engine light to turn on.
