Mercedes-Benz S350 DEF refill issue with no start, suspected electrical problem on Mercedes-Benz S350

Some Mercedes-Benz S350 owners report experiencing issues related to DEF refill problems that prevent the car from starting, often linked to suspected electrical issues. These owners may find that even after topping off the DEF, the warning light remains on, indicating a potential DEF sensor problem. Additionally, failures within the AdBlue system can lead to a no-start condition if there are low DEF fluid levels or faults in the SCR system. Common no-start problems reported include the engine clicking without starting, dying shortly after starting, or turning over but failing to ignite. Owners should also be aware of potential component failures such as clogged diesel particulate filters, DEF-heater malfunctions, and issues with exhaust pressure sensors, which can complicate starting. It is highly recommended that owners seek prompt inspection at a dealership, especially for emissions-related concerns, to avoid receiving a "10 starts remaining" message that could limit warranty options.