What is an SCR Fault?
3 Answers
When the engine SCR fault light illuminates, it indicates a malfunction in the corresponding component functions. Below are the relevant details: Fault Causes: Insufficient urea level (you can check this yourself to see if the urea level is normal), nitrogen oxide sensor failure, urea injector failure, urea injector clogging, urea pump fault light. There are two scenarios for the engine fault light: A yellow symbol light indicates an engine fault that affects engine operation and requires maintenance. A red symbol light signifies a severe engine fault that requires immediate repair. In emergency driving situations on special road conditions, it's crucial to closely monitor the engine's operating status. Note: All electronically controlled injection engines come with self-protection control systems to prevent engine stalling.
I have dealt with many SCR fault situations, which mainly refer to problems with the Selective Catalytic Reduction system in diesel vehicles. The core issue is that the exhaust treatment device is not functioning properly. The most common causes include running out of AdBlue urea solution or using poor-quality fluid, which triggers system warnings. Nozzle clogging is also frequent, especially after driving in dusty environments. If not addressed promptly, the vehicle may enter a derate mode, where engine power is limited, resulting in poor performance and higher fuel consumption. Additionally, sensor failures, such as NOx sensors or temperature sensors, can also cause SCR issues. Accurate diagnosis requires reading fault codes with a diagnostic tool. It is recommended that vehicle owners regularly check urea levels, ensure the use of genuine AdBlue, and clean the nozzles every six months to prevent problems. If issues arise, seek professional repair services to avoid exceeding emission standards and violating environmental regulations. Paying attention to these small details during routine maintenance can save you from major troubles.
I remember encountering an SCR fault while driving a diesel pickup truck. The dashboard warning light came on, and the vehicle felt like it was being held back with reduced power. I immediately pulled over to check and found the urea tank was empty. I went to a gas station, bought a bottle of AdBlue, poured it in, and reset the system, which restored normal operation. Later, I consulted an experienced mechanic and learned that the SCR system relies on urea to break down exhaust gases. If the urea level is low or contaminated, the system will shut down. Sensor issues are also common, such as false fault codes. Prevention is key—glance at the dashboard before each trip to ensure the urea level is sufficient. Ignoring it could lead to emissions failure or power limitations, affecting driving safety. Develop good habits and don’t neglect refilling urea; it can prevent breakdowns on the road. Such faults aren’t overly complex, but they require attentive maintenance—don’t wait until the problem worsens to act.
