P21B0 Code: Easy Steps to Solve It
The P21B0 trouble code is a diagnostic trouble code (DTC) that indicates an issue with the vehicle’s reductant level sensor circuit. Specifically, it signifies that the Reductant Level Sensor ‘C’ is reporting a high voltage condition. This sensor is critical in vehicles equipped with diesel engines that utilize Diesel Exhaust Fluid (DEF) to reduce emissions. Understanding this code is essential for vehicle owners and DIY