Have a SD115 Volvo smooth drum roller that has been having regen issues since i've been around here (2 1/2 years) Local Volvo dealer has been out on machine several times and usually runs 30-40 hrs and same code pops up again. Diagnostic code that shows up on dash is 326-14 aftertreatment system; special instruction. Only have the ability to see what the code is through the monitor, no testing functionality outside of the dealer, or so i'm told. Anyone have any similar experience or advice that could possibly lead us to a solution to the root cause of the issue? Machine has 3300 hrs on it. Has dpf filter and no DEF system.