- Faulty oxygen sensor: The oxygen sensor measures the amount of oxygen in the exhaust gas, which is used by the engine control unit (ECU) to adjust the air-fuel mixture. A faulty oxygen sensor can send incorrect signals to the ECU, causing the engine to run rich or lean.
- Vacuum leaks: Vacuum leaks can cause the engine to run lean, which can also trigger the check engine light.
- Faulty fuel injector: A faulty fuel injector can cause the engine to run rich or lean, which can trigger the check engine light.
- Catalytic converter failure: A failed catalytic converter can cause the engine to run inefficiently, which can trigger the check engine light.
Diagnosis:
To diagnose the cause of the check engine light, a diagnostic scan tool is needed to read the diagnostic trouble codes (DTCs) stored in the ECU. The DTCs will indicate the specific component or system that is causing the problem.
Repair:
Once the cause of the check engine light has been diagnosed, the appropriate repairs can be made. In the case of a faulty oxygen sensor, the sensor will need to be replaced. If the cause is a vacuum leak, the leak will need to be found and repaired. If the cause is a faulty fuel injector, the injector will need to be replaced. If the cause is a failed catalytic converter, the converter will need to be replaced.
Maintenance:
To prevent future problems with the oxygen sensor and other emissions control components, it is important to keep up with regular maintenance. This includes changing the engine oil and filter at the recommended intervals, using high-quality fuel, and avoiding excessive idling and overloading.
