The engine warning light may illuminate due to the following 7 main reasons: Sensor malfunction: The sensors involved include those for coolant temperature, crankshaft position, air flow, intake temperature, oxygen levels, etc. When these sensors are damaged, have poor connections, or their signals are interrupted, the vehicle's ECU cannot accurately obtain engine data, triggering the engine warning light. Fuel and oil quality issues: Failure to use the fuel and oil types specified by the manufacturer may cause engine wear, leading to the warning light activation. Poor fuel mixture combustion: This can result in engine carbon buildup or knocking. Once detected by the oxygen sensor and reported to the ECU, the warning light will illuminate as an alert. Causes include faulty spark plugs, ignition coils, fuel pumps, or clogged fuel lines. Turbocharger problems: Issues with the intake boost pipes or turbocharger can also trigger the engine light. The most common is turbocharger damage, accompanied by symptoms like oil leaks, excessive oil consumption, reduced power, metallic noises, or blue/black smoke from the exhaust. Intake system issues: Problems with the car's intake can lead to engine pipe blockages, potentially causing the warning light to turn on. A dirty or uncleaned air filter is a frequent culprit. Exhaust system problems: Exhaust faults, such as malfunctions in the rear oxygen sensor, catalytic converter, exhaust camshaft, or bearings, can activate the engine light. The catalytic converter is most commonly affected, especially when using leaded gasoline or improper oil additives, or after physical damage. Anti-theft system malfunction: If the car's electronic anti-theft system fails or there's a mismatch between the anti-theft controller and the engine ECU, the engine may not operate correctly, and the warning light will illuminate. Steps to address an illuminated engine warning light: First, check if the engine is running normally—look for shaking, black smoke, etc. If abnormalities exist, avoid restarting the engine. Note: Never restart if the light is red. If the engine starts, turn it off and wait 5-10 minutes. Then, without pressing the brake, press the start button once or turn the key halfway to the 'on' position (without engaging the clutch). The car will perform a self-check; observe if the warning light turns off after 5-10 seconds. If the light remains on, visit a service center promptly. Technicians can use diagnostic tools to read fault codes, identify the issue, and perform targeted repairs.
