What does it mean when the smart engine fault light is on in yellow?
2 Answers
Here are the reasons why the smart engine fault warning light stays on in yellow: 1. Poor engine combustion is the main reason for the engine fault light to come on. 2. Engine knocking. 3. Poor fuel quality, unclean engine cylinders, and accumulated carbon deposits. 4. If these factors are ruled out and the warning light remains on, the warning light itself may be faulty and can be repaired or replaced. 5. The engine fault light is a relatively common type of warning light. There are dozens of different types of sensors among engine components, and a fault in any one of them can cause the engine fault light to come on. In this case, it is necessary to identify the meaning of the fault light: a yellow light indicates that a fault has occurred, but the vehicle can continue to drive, though it requires inspection and repair as soon as possible; a red light indicates that a fault has occurred and the vehicle must be stopped immediately, as it cannot continue to drive to avoid danger.
The yellow engine warning light on the dashboard is your car's way of tattling, indicating potential minor issues with the emission system. Common causes include carbon buildup or damage to the oxygen sensor, leading to inaccurate engine data; a low-efficiency catalytic converter affecting environmental performance; or problems with ignition coils/spark plugs causing incomplete combustion. I remember once during a long drive when the light came on—turned out to be a loose fuel cap triggering the warning due to vapor leakage. If the light's yellow, the car remains drivable, but don't delay. It's best to scan for trouble codes using an OBD scanner to pinpoint the issue. Cars with neglected maintenance are prone to this—regular carbon cleaning and sensor replacements can prevent minor issues from escalating into costly repairs.
