If the engine fault light comes on, follow these steps: First, check whether the engine is running normally, such as whether there is shaking, black smoke, or difficulty starting. If any of these issues occur, avoid restarting the engine. Note: If the light is red, do not restart the engine under any circumstances. If the engine is running normally and the vehicle can still be driven, visit a service station as soon as possible to diagnose the issue. The service station can easily read the fault code using a portable diagnostic tool, allowing for targeted repairs. If the engine is running normally, the owner can also try gently reconnecting all wiring harness connectors, as a loose connection may be the cause. Alternatively, repeatedly turning the key to the ON position may reset the light. Generally, the engine fault light may come on due to the following seven reasons: Sensor failure: Sensors such as the coolant temperature sensor, crankshaft position sensor, air flow sensor, intake temperature sensor, and oxygen sensor may become damaged, have poor connections, or lose signal transmission. When the ECU cannot accurately obtain engine data, the fault light will illuminate. Fuel or oil quality issues: If the recommended fuel or engine oil is not used as specified by the manufacturer, engine wear may occur, triggering the fault light. Poor combustion of the air-fuel mixture: Poor combustion can lead to engine carbon buildup or knocking. When detected by the oxygen sensor and reported to the ECU, the fault light will illuminate as a warning. Issues such as faulty spark plugs, ignition coils, fuel pumps, or clogged fuel lines can cause poor combustion. Turbocharger problems: Issues with the intake boost system or turbocharger can also trigger the engine fault light. The most common issue is turbocharger damage, often accompanied by oil leaks, excessive oil consumption, reduced power, metallic noises, or blue/black smoke from the exhaust. Intake problems: Clogged engine intake passages can lead to the fault light coming on. A dirty air filter that hasn’t been cleaned regularly can cause intake issues. Exhaust problems: Exhaust system faults, such as issues with the rear oxygen sensor, catalytic converter, exhaust camshaft, or bearings, can trigger the fault light. The catalytic converter is the most common culprit. Using leaded gasoline, lead/silicon-based oil additives, physical damage to the catalytic converter, or fuel system issues can cause catalytic converter failure. Anti-theft system malfunction: If the car’s electronic anti-theft system fails or the anti-theft controller is incompatible with the engine ECU, the engine may not function properly, and the fault light will illuminate.
