What does the DEF light mean in Jiangling vehicles?

[LilyLynn]

Jiangling vehicle's DEF warning light indicates the auxiliary water tank indicator. When this light is on, it means the auxiliary water tank is low on water, and the fault can be resolved by adding water. The auxiliary water tank is a rectangular plastic box located under the driver's seat. Here's an introduction to the vehicle's auxiliary water tank: The main function of the automobile auxiliary water tank is that when the engine temperature is high, the liquid expands, and some coolant flows into the auxiliary tank through the radiator cap; when the temperature drops and the cooling system pressure becomes negative, the system draws coolant from the auxiliary tank back into the cooling system through the radiator cap. The auxiliary tank also has corresponding markings to indicate the fluid level.