B50D03 Mercedes Fault Code :
Read the description of B50D03 in ACM21T and the engine lights up for ACM21T Aftertreatment Control Module code, there are some possible causes for it.
The power supply for components 17B11: Exhaust pressure sensor upstream of diesel particulate filter (DPF) and (or) 17B12: Exhaust pressure sensor downstream of diesel particulate filter (DPF) has a short circuit to positive.