What are the reasons for fast consumption of urea?

[SawyerRose]

There are several main reasons for the fast consumption of urea: Nozzle issues: Problems with the urea nozzle, such as clogging, poor atomization, or direct leakage in the urea pipeline; Sensor malfunction: The exhaust temperature sensor sends a signal to the computer board at 180 degrees, prompting the nozzle to start spraying urea. If the exhaust temperature sensor malfunctions, the urea may start spraying before reaching 180 degrees, leading to excessive urea consumption; Urea pump problems: Internal failures in the urea pump can cause pressure build-up failure, or in the case of air-assisted urea pumps, it can more easily result in excessive urea consumption.

[VanBriella]

A few days ago, my neighbor Old Zhang also complained that his truck's urea was being consumed too quickly. After some discussion, we realized there are some key factors at play. The most common cause is prolonged heavy-load highway driving—the engine works harder and requires more urea injection to treat exhaust emissions. Last month, while helping my cousin inspect his tractor, I found the urea nozzle leaking like a faucet, wasting nearly half a bucket. Another often-overlooked issue is using cheap urea with insufficient concentration—the onboard computer detects substandard emissions and automatically doubles the injection rate. Finally, don’t forget to check the exhaust temperature sensor—if it’s faulty and falsely reports low temperatures, the system will keep injecting urea to maintain warmth!

[SanEllie]

When repairing vehicles, I often encounter drivers reporting abnormal urea consumption. The first step is to check these areas. A stuck pressure valve in the urea pump can double the injection volume—I encountered this situation when repairing a logistics company's vehicle last time. Sensor misreporting is also common, especially when the NOx sensor readings are high, causing the ECU to think pollution is severe and inject more urea. Don't assume it's only a hardware issue; improper software upgrades can also disrupt the injection program. Additionally, driving in mountainous areas like Yunnan, Guizhou, and Sichuan during summer causes engine temperatures to rise, leading to a surge in nitrogen oxides and naturally increasing urea consumption, which is a normal phenomenon.

[LilaFitz]

Don't panic if you find DEF (Diesel Exhaust Fluid) being consumed quickly, first check three key points. Substandard DEF with inadequate concentration is the primary culprit, as the system increases usage to meet emission standards. Clogged or leaking nozzles can waste your money. Poor engine combustion also contributes—excessive carbon deposits and inaccurate fuel injection increase exhaust pollution, forcing the DEF system to work overtime. Another detail: frequent short trips with repeated cold starts lead to excessive injection for rapid system warm-up, making urban delivery vehicles consume more DEF than long-haul trucks. Simple maintenance can save costs: inspect nozzles monthly, use certified DEF, and clean carbon deposits before long trips.