What Causes the Engine Yellow Light on the Tachometer to Illuminate?

[DelNevaeh]

There are two main reasons why the engine yellow light on the tachometer illuminates, with the primary reason being vehicle self-inspection. Below are the relevant explanations: 1. Vehicle Self-Inspection: When the car's power is turned on, the vehicle undergoes a self-inspection. During this time, not only the engine yellow light but also other fault lights will illuminate simultaneously before turning off together. 2. Engine Fault: If the engine's yellow fault light remains illuminated after the car is started, it indicates that the ECU is alerting to an engine fault. For instance, sensors such as those for water temperature, crankshaft position, air flow, intake temperature, and oxygen sensors, when damaged, have poor contact, or experience signal interruption, the car's ECU cannot accurately obtain engine data, leading to the illumination of the engine fault light.