What Causes the Engine Warning Light to Illuminate in a Passat?

[DiAlina]

Passat engine warning light illumination is primarily caused by severe cylinder carbon buildup or poor combustion conditions, as detailed below. Severe Cylinder Carbon Buildup: After prolonged use, engines inevitably accumulate carbon deposits. These deposits alter the engine's designed parameters and, due to their unstable nature and heat retention properties, can cause uncontrolled ignition within the engine, leading to knocking. This condition triggers the engine warning light. Poor Combustion Conditions: Suboptimal engine combustion is a major reason for the warning light activation. In automotive design, oxygen sensors are installed to monitor combustion efficiency, ensuring optimal engine performance and longevity. Poor combustion not only increases environmental pollution but also results in fuel wastage and accelerated engine wear.