What Causes the Car Engine Malfunction Light to Flash?
2 Answers
The engine malfunction light may illuminate due to the following seven main reasons: Sensor malfunction: The sensors involved include those for coolant temperature, crankshaft position, air flow, intake air temperature, and oxygen sensors. When these sensors are damaged, have poor contact, or experience signal interruption, the vehicle's ECU cannot accurately obtain engine data, triggering the malfunction light. Fuel or oil quality issues: Failure to use the fuel and oil as specified by the manufacturer may cause engine wear, leading to the malfunction light turning on. Poor fuel mixture combustion: Poor combustion can result in engine carbon buildup or knocking. Once detected by the oxygen sensor and reported to the ECU, the malfunction light will illuminate as a warning. Issues such as faulty spark plugs, ignition coils, fuel pumps, or clogged fuel lines can all lead to poor fuel mixture combustion. Turbocharging problems: Issues with the intake boost pipes or turbocharger can also cause the engine malfunction light to illuminate. The most common issue is a damaged turbocharger, often accompanied by symptoms like oil leaks, excessive oil consumption, reduced power, metallic noises, or blue/black smoke from the exhaust. Intake problems: If the vehicle's intake system is compromised, it may lead to clogged engine pipes, and in severe cases, trigger the malfunction light. A dirty or uncleaned air filter can cause intake problems. Exhaust problems: Exhaust system faults can also cause the engine malfunction light to illuminate. Common causes include faulty rear oxygen sensors, catalytic converters, exhaust camshafts, or bearings. The catalytic converter is the most frequent culprit, often damaged by leaded gasoline, lead/silicon-based oil additives, physical impacts, or fuel system issues. Anti-theft system malfunction: If the vehicle's electronic anti-theft system fails or the anti-theft controller is incompatible with the engine ECU, the system may prevent the engine from operating correctly, accompanied by the malfunction light. If the engine malfunction light illuminates, follow these steps: First, check if the engine is running normally. Look for symptoms like shaking or black smoke. If present, avoid restarting the engine. Note: Never restart the engine if the light is red. If the engine can start, turn it off and wait 5-10 minutes. Without pressing the brake, press the start button once or turn the key halfway to the "ON" position (without engaging the clutch). The vehicle will perform a self-check. After 5-10 seconds, observe if the malfunction light turns off. If the light remains on, visit a service center as soon as possible. Technicians can use a portable diagnostic tool to read fault codes, identify the issue, and perform targeted repairs.
I've been driving for decades and have seen many instances of the engine malfunction indicator light flashing. The most common issue is misfiring, which means the engine's ignition in a certain cylinder is abnormal, possibly due to aging spark plugs or a faulty ignition coil. The car will noticeably shake, sounding like a tractor. Another possibility is a problem with the oxygen sensor, which monitors the oxygen content in the exhaust—if it detects an anomaly, the light will flash. The most serious scenario is prolonged engine misfiring, which can cause high temperatures to damage the catalytic converter, leading to repair costs of at least several thousand dollars. I remember one winter when the light flashed, and I kept driving anyway, only to end up with a ruined catalytic converter—something I deeply regret. My advice is to immediately find a safe place to stop when the light flashes and avoid continuing to drive. Have a mechanic use a diagnostic tool to read the trouble codes and pinpoint the issue. Regularly checking spark plugs and the fuel system can prevent many problems, as safe driving is ultimately the top priority.
