Why does the engine light come on after an oil change?
2 Answers
There are usually the following reasons for the engine fault light to come on: 1. Poor fuel quality: If the engine fault light comes on shortly after an oil change, it is likely due to substandard gasoline causing incomplete combustion, which triggers the engine fault light. 2. Spark plug carbon deposits: Carbon buildup on the spark plugs or prolonged use of spark plugs can lead to poor engine performance, resulting in difficulties starting, unstable idling, poor idle quality, backfiring during acceleration, and excessive exhaust emissions, which can also cause the engine fault light to illuminate. 3. Other reasons: Faults in the oxygen sensor, knock sensor, or other engine electronic control systems can also cause the engine fault light to come on.
Last time I just changed the engine oil and the engine light came on, which was quite puzzling. It turns out that the oil pressure sensor might have been accidentally bumped during the oil change, causing it to falsely report a fault. Or the oil type was incorrect, such as using oil that was too thick or too thin, and the computer detected abnormal pressure, triggering the warning light. Another common reason was that I didn't tighten the oil pan bolt properly, resulting in oil leakage and a drop in oil pressure. I suggest first checking the oil dipstick to see if the oil level is normal; if it's low, quickly top it up with some new oil. If the light is still on, go to a repair shop to read the fault code with a diagnostic tool—it might be a damaged sensor that needs replacement. It's best not to disassemble the car yourself, as you might end up damaging more components. Regular maintenance with standard oil and avoiding random additives can prevent such problems.
