Why is the engine malfunction indicator light on?
4 Answers
The reasons for the engine malfunction indicator light being on: 1. Sensor damage, poor contact, or signal interruption; 2. Poor engine maintenance causing engine malfunction; 3. Failure to add fuel or engine oil as required, leading to severe engine wear; 4. Issues with the engine's spark plugs, ignition coils, fuel pump, or fuel system can cause poor combustion of the engine's air-fuel mixture; 5. The car's air filter is dirty and not cleaned regularly. The engine malfunction indicator light is a yellow light resembling an engine outline. If this warning light comes on or the pressure gauge indicates too high, the first step is to turn off the engine, pull out the engine oil dipstick, and check if the oil level is between the minimum and maximum marks. If the oil level is normal, a technician should be consulted to determine the cause of the light being on.
Last week I drove my car to the repair shop with the warning light on. The experienced mechanic said there could be many reasons for the engine warning light. It might be a fuel system issue, like clogged fuel injectors causing incomplete combustion; or an ignition system failure, such as worn spark plugs or faulty ignition coils. There could also be an oxygen sensor error - this component monitors exhaust conditions, and if broken, it affects fuel consumption. Severe carbon buildup can also trigger the computer's warning. The most troublesome issues involve short circuits in sensor circuits. I once encountered this problem due to poor fuel quality, and it resolved after switching gas stations. It's advisable not to delay and get it checked promptly to prevent major repairs.
With over ten years of experience in auto repair, I've encountered dozens of common scenarios where the engine warning light comes on. The most ordinary one is when the fuel tank cap isn't tightened properly, causing fuel vapor leakage and triggering the sensor alarm. There are numerous exhaust system issues—whether it's a clogged catalytic converter or a faulty oxygen sensor, they'll light up the warning. Problems with spark plugs or ignition coils can also trigger warnings, especially during cylinder misfires when the dashboard light flashes rapidly. Hidden issues like air intake system leaks or vacuum tube ruptures are also common. The most straightforward solution is to use a diagnostic scanner to read the trouble codes—targeted fixes are far better than random guesses.
Last month, the engine light in my SUV suddenly turned yellow, and I took it to the 4S dealership for a check-up that lasted half an hour. The technician said the sensor was overly sensitive, and it would trigger an alarm if the fuel quality was slightly poor or if low-quality gasoline was used. However, serious issues like timing chain misalignment or insufficient cylinder pressure could also cause the light to come on. A dirty electronic throttle or a faulty crankshaft sensor could also be the culprits. They recommended focusing on cleaning the fuel injectors and throttle during maintenance, and now, after two weeks of driving, the light hasn't come back on.
