What Causes a Truck Not to Consume Urea?
2 Answers
If you notice that the vehicle's urea has not been consumed or the emission warning light is on, it may indicate that the SCR system is not functioning (commonly referred to as not "burning" urea). This issue cannot be resolved by DIY methods and requires immediate inspection and repair at a professional 4S shop. Possible specific causes include: damaged urea pump, blocked urea lines, or clogged nozzles. The impacts are as follows: 1. Environmental Pollution: Diesel vehicles without urea can severely harm the ecological environment, and it is also prohibited by national laws and regulations. 2. Reduced Power: This is not a direct result of not using urea, but rather because the engine's electronic control system limits torque output when it detects no urea injection and excessive tailpipe emissions. 3. Damage to the SCR Injection System: Long-term absence of urea may cause crystallization blockages in the SCR system's nozzles, lines, and urea pump, or damage due to high temperatures.
I've been driving trucks for over twenty years, and common issues with urea not being consumed mainly include the urea solution not being topped up, leading to system failure. Sensors are also prone to problems, such as faulty level sensors misjudging the presence of liquid, or nozzle blockages due to impurities, especially when using off-brand urea. Crystallization clogging the pipes is worse in winter. There are also cases where the engine control unit misjudges and assumes an error, preventing injection. Electrical faults like blown fuses or loose wiring can affect power supply. Exhaust system blockages can indirectly cause system activation failure. Not addressing these issues promptly can lead to the emission light coming on, the vehicle being speed-limited, insufficient power affecting delivery efficiency, and even fines. I've encountered these multiple times; timely checks on fluid levels and using genuine urea can avoid most troubles. Regular maintenance is key—replacing sensors or cleaning nozzles isn't hard to resolve. These small issues can add up over time during safe driving, so they should be taken seriously.