P246309 and P245328 point to the DPF differential pressure sensor on the OM651 diesel. The sensor measures soot levels inside the filter. When it fails or gives an incorrect reading the ECU cannot calculate soot load accurately. Most of the time it is the sensor that has failed, not the DPF itself. Get it diagnosed before spending money on a filter replacement.
The engine control unit calculates DPF soot load using the differential pressure sensor across the diesel particulate filter.
On this OM651 vehicle, fault codes P246309 and P245328 were stored, indicating excessive soot content and a pressure sensor signal offset.
Live data showed an implausible differential pressure reading compared to expected values at idle and under light load.
Pressure hoses to the sensor were inspected and confirmed to be clear with no visible blockage or restriction.
The fault was traced to the differential pressure sensor signal being out of specification.
The differential pressure sensor was replaced (A0009051119).
After replacement, live data returned to normal values and DPF monitoring operated correctly.
A guided regeneration may be required depending on soot load level stored in the ECU.
Do not replace the DPF before the sensor has been checked. A faulty pressure sensor is far more common and significantly cheaper to fix. Always get a proper diagnostic before committing to parts.