What does it mean when the SCR light in a car is on?
2 Answers
When the SCR light in a car is on, it indicates a malfunction in the Selective Catalytic Reduction system, which requires timely inspection and repair. Below is an extended introduction: 1. Introduction to SCR: SCR stands for Selective Catalytic Reduction system. Its function is similar to the three-way catalyst in gasoline vehicles. It uses a catalyst in the traditional muffler, along with a urea supply system and injection control system, primarily to treat NOx in diesel engines. Simply put, it processes exhaust gases. 2. Causes of the malfunction: The main causes of such malfunctions include sensor damage, loose or short-circuited sensor connectors, and related wiring harness faults. It is necessary to seek professional inspection and repair.
The SCR light being on indicates an issue with the vehicle's Selective Catalytic Reduction system, most likely due to low urea solution levels or a faulty sensor. Having driven a diesel SUV myself, I've encountered this several times. The first step is to pull over and check the AdBlue fluid level—top it up immediately if it's low, as the system relies on this to reduce exhaust pollution. If the light remains on after refilling, it could be a clogged pump or electrical problem, requiring a quick visit to the repair shop for a fault code scan. Ignoring this may lead to emission fines or even trigger the vehicle's speed-limiting mode, which is hazardous. Designed to purify harmful nitrogen oxides, neglecting the SCR light harms both the environment and performance. It's advisable to develop a habit of regularly checking AdBlue levels to prevent unexpected disruptions to your journey.
