What Causes the Persistent Illumination of the Engine Warning Light in the Chevrolet Cavalier?

[Boromir]

The persistent illumination of the engine warning light in the Chevrolet Cavalier can be attributed to the following 7 main reasons: Sensor Malfunction: The sensors in question include those for coolant temperature, crankshaft position, air flow, intake air temperature, and oxygen sensors. When these sensors are damaged, have poor connections, or experience signal interruptions, the vehicle's ECU cannot accurately obtain engine data, triggering the engine warning light. Fuel and Oil Quality Issues: Failure to adhere to the manufacturer's specifications for fuel and oil can lead to engine wear, causing the warning light to illuminate. Poor Combustion of Air-Fuel Mixture: Inefficient combustion can result in engine carbon buildup or knocking. Once detected by the oxygen sensor and reported to the ECU, the warning light will activate as an alert. Issues such as faulty spark plugs, ignition coils, fuel pumps, or clogged fuel lines can all lead to poor combustion. Turbocharger Problems: The intake boost piping and turbocharger can also cause the engine warning light to come on. The most common issue is turbocharger damage, often accompanied by symptoms like oil leaks, excessive oil consumption, reduced power, metallic noises, and blue or black smoke from the exhaust. Intake Issues: Problems with the vehicle's intake system can lead to clogged engine pipes, and in severe cases, trigger the engine warning light. A dirty air filter that hasn't been cleaned regularly can cause intake problems. Exhaust System Issues: Exhaust faults can also illuminate the engine warning light. Common causes include faulty rear oxygen sensors, catalytic converters, exhaust camshafts, and bearing wear, with the catalytic converter being the most frequent culprit. The use of leaded gasoline, lead or silicon-based lubricant additives, physical damage to the catalytic converter, or fuel system malfunctions can all contribute to catalytic converter failure. Anti-Theft System Malfunction: If the vehicle's electronic anti-theft system fails or if there is a mismatch between the anti-theft controller and the engine electronic controller, the anti-theft system can prevent the engine from operating normally, accompanied by the illumination of the engine warning light. Steps to Address the Illuminated Engine Warning Light: First, check if the engine is running normally and look for symptoms such as shaking or black smoke. If present, avoid restarting the engine. Note: Do not restart the engine if the red warning light is on. If the engine can be started, 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 depressing the clutch. The vehicle will enter self-diagnosis mode upon powering up. After 5-10 seconds, observe whether the warning light on the dashboard turns off. If the warning light remains on, proceed to a service center as soon as possible. Technicians can use a portable diagnostic tool to retrieve fault codes, identify the issue, and perform targeted repairs.