What Causes the Yellow Engine Light to Illuminate?

[SaraMarie]

Car engine yellow light is on due to engine malfunction. There are various reasons that can cause the engine malfunction light to illuminate, including sensor-related faults such as coolant temperature sensor, crankshaft sensor, oxygen sensor, etc., as well as other issues like spark plug failure, ignition coil failure, fuel pump failure, fuel line blockage, etc. The engine fault signal is emitted by the ECU, which controls all electronic components of the engine, including electronic throttle, fuel injectors, alternator, fuel pump, etc., covering various systems such as intake, exhaust, fuel, ignition, timing, and more.