What Causes the Engine Warning Light to Illuminate in the Avalon?

[VanBrynlee]

The engine warning light in the Avalon may illuminate due to the following 7 main reasons: Sensor malfunction: Sensors such as coolant temperature, crankshaft position, air flow, intake temperature, and oxygen sensors may become damaged, have poor connections, or experience signal interruptions. When the car's ECU cannot accurately obtain engine data, the engine warning light will illuminate. Fuel or oil quality issues: If fuel or engine oil is not added according to the manufacturer's requirements, it may cause engine wear, leading to the warning light turning on. Poor combustion of the air-fuel mixture: Poor combustion can cause engine carbon buildup or knocking. When detected by the oxygen sensor and reported to the ECU, the warning 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 combustion. Turbocharger issues: Problems with the intake boost pipes or turbocharger can also trigger the engine warning light. The most common issue is a damaged turbocharger, accompanied by symptoms like oil leaks, excessive oil consumption, reduced power, metallic noises, or blue/black smoke from the exhaust. Intake issues: If the car's intake system is compromised, it may lead to clogged engine pipes, and in severe cases, the engine warning light will illuminate. A dirty or uncleaned air filter can cause intake problems. Exhaust issues: Exhaust system faults can also trigger the engine warning light. 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 lubricant additives, physical impacts, or fuel system malfunctions. Anti-theft system malfunction: If the car's electronic anti-theft system fails or the anti-theft controller does not match the engine ECU, the anti-theft system may prevent the engine from operating normally, and the warning light will illuminate. If the engine warning light is on, follow these steps: First, check if the engine is running normally, such as whether there is shaking or black smoke. If so, avoid restarting the engine. Note: Do not restart the engine if the red warning light is on. 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 pressing the clutch). The car will enter self-check mode. After 5-10 seconds, observe whether the warning light turns off. If the light remains on, visit a service center as soon as possible. Technicians can use a diagnostic tool to read the fault code and perform targeted repairs.