What are the reasons for the post-processing fault light to illuminate?
2 Answers
When the fault light illuminates, it indicates that there is a problem with the corresponding component's function. Common reasons for the SCR post-processing light to illuminate include: insufficient urea level, nitrogen oxide sensor failure, urea nozzle failure, urea nozzle blockage, urea pump failure, etc. Below is more detailed information about post-processing fault lights: 1. Introduction: On commercial vehicle dashboards, there are two common fault indicator lights: SYS and MIL. The SYS light usually refers to the engine fault indicator; MIL typically points to the post-processing system. 2. Explanation: Once it illuminates, it means there is an issue with the related post-processing system. It is necessary to understand the activation and deactivation rules of the post-processing fault light before clearing the fault code.
I've been driving a diesel vehicle for several years, and that post-treatment fault light always gives me a headache. Common causes include running out of urea or poor-quality urea, AdBlue system blockage, excessive carbon buildup in the Diesel Particulate Filter (DPF) leading to regeneration failure, malfunctioning sensors like NOx or temperature sensors, and aging wiring or blown fuses. I remember the last time the light came on was due to low urea fluid level, and it went away after refilling; but if regeneration fails frequently and the DPF gets severely clogged, it can affect engine power. If not addressed promptly, fuel consumption may increase or even lead to speed limitation. In such cases, I usually check the urea tank as soon as possible or take it to a repair shop for diagnosis. After all, poor maintenance of the emission system not only damages the vehicle but also results in fines. As a routine, I make it a habit to clean related components every 5,000 kilometers—prevention is better than cure, and driving safety comes first.
