What are the consequences of running out of urea in a truck?
2 Answers
Here are the consequences of running out of urea in a truck: 1. Impact on the vehicle: If urea is not injected, nitrogen oxide emissions will be worse than those of a National III vehicle. Long-term absence of urea circulation can easily cause crystallization blockage or high-temperature damage to the nozzle, pipelines, and urea pump, resulting in very expensive repairs. Not adding urea, adding water, or diluting urea with water will trigger the emission warning light, limit torque, and make the vehicle very sluggish. However, it does not affect the engine's lifespan and performance, the catalyst carrier, or the exhaust temperature and NOx sensors. 2. Impact on fuel consumption: Manufacturers must input the urea sensor's data into the engine control unit (ECU) when producing National IV engines. Once the sensor data indicates that the urea is depleted or missing, the ECU will control the engine's operating conditions, making the engine feel underpowered. This lack of power requires more throttle input, naturally increasing fuel consumption. Even so, the engine still cannot achieve full-load power output.
When I drove a truck before, I didn’t notice the urea ran dry, and the vehicle immediately went into limp mode—power dropped, couldn’t go fast, and fuel consumption spiked. Without urea, the SCR system can’t process nitrogen oxides in the exhaust, leading to excessive emissions that may result in fines. Even worse, prolonged operation like this can damage the catalytic converter, costing thousands in repairs. My advice: check the urea tank before long trips, refill AdBlue regularly, and avoid sudden stops. The vehicle also has sensor warnings—act as soon as the light comes on. In short, running dry not only hurts your wallet but also compromises road safety.
