They all cleared out and all the non-functioning components resumed their functionality. Things to consider for doing such repair: brake fluid for loosing the stubborn sensor, try working the top portion of sensor out first. Check the resistance value: the old faulty sensor measured 575 kOhms, whilst the new one was at 3.2 kOhms. Posted April 29, 2017. "Aftertreatment Hydrocarbon doser". Fmi 4: voltage is below or shorted circiut. Or ground is shorted. Possible symptoms are "regen not possible" check engine light and MIL light. It's says possible fixes are "check wire harness and/or replace doser. Quote. Experience: Volvo/Mack Master Tech, Certified with Cummins, Eaton, GM, Hino, Detroit Diesel. Verified. ... prostar 2008 with cummins isx engine and i have 3 codes Can you pls tell me what they are for and what they mean Spn 3556 fmi 31 sa0 Spn 3556 fmi 5 sa 0 S.