What are the reasons for the MIL malfunction indicator light to illuminate?
2 Answers
The malfunction (MIL) light or check engine warning light illuminates due to a fault in the engine system. Here is relevant information: 1. Surface contamination: The MIL light staying on could also be caused by 'false data,' such as dust accumulation on some sensors, dirty engine exterior surfaces, or internal damage. It is recommended to clean the surfaces of potentially faulty sensors and then attempt to reset the system. 2. Working principle: The onboard diagnostics system (OBD) monitors whether the exhaust emissions meet the standards corresponding to the engine's operating conditions. If the emissions exceed the standards, an alarm is triggered, and the fault information is stored in the powertrain control module (PCM).
There are several common reasons for the malfunction indicator light to come on. From my experience, the most frequent cause is an oxygen sensor issue—if it inaccurately detects exhaust composition, the light will illuminate. Another possibility is a loose fuel cap, leading to abnormal fuel tank pressure. Additionally, aging ignition coils can cause insufficient sparking, resulting in engine shaking and poor acceleration. Even a dirty mass airflow sensor can affect intake volume calculations. Although it's just a small light, ignoring it may lead to skyrocketing fuel consumption or severe pollution. I once drove hundreds of kilometers with it on and ended up spending thousands on major repairs. Therefore, it's crucial to visit a repair shop promptly for code diagnosis. Regular maintenance, such as using quality fuel and replacing filters periodically, can help reduce faults.
