Hogg presented this chart this year at the NASTC conference just as he did in 2023, an analysis of data from a variety of fault-code monitoring devices to determine the top five areas of trouble in modern diesels. It will come as no surprise that aftertreatment systems in general topped the rankings, accounting for a whopping 57% of all fault codes seen in the sample. Hogg's 2023 presentation about effective PM approaches for owners of SCR-equipped diesels you can sit in on via the Overdrive Radio podcast below or at this link.