BMW AdBlue system faults: symptoms and costs
Photo by Volodymyr Proskurovskyi on Unsplash The AdBlue warning appears on the iDrive screen. You top the fluid up. A week later, the warning is back, and this time it is not going away. The mileage countdown starts, telling you that the engine may not restart once the remaining range reaches zero. You have not necessarily run out of fluid. You may have an AdBlue or SCR system fault, which is an entirely different problem. BMW's AdBlue system is more complex than simply having a tank that needs topping up. On BMW diesels equipped with SCR, the system can include an AdBlue tank and heating system, pump and dosing components, BMW NOx sensors , an SCR catalyst and associated electronics. When one of these components develops a fault, adding more AdBlue will not necessarily clear the warning. Understanding the difference between a low-fluid warning and a genuine system fault can save you from repeatedly topping up a tank when the actual problem is a sensor, dosing component, wiring f...