manolumber Posted December 9, 2014 Share Posted December 9, 2014 Text says "mechanical system not responding". This is a code for the DPF aftertreatment system. The DPF injector is new, the fuel line is clear. Next step says to go after the DPF module which contains a couple of valves and a fuel pressure switch. Guided diagnostics red flagged the fuel pressure sensor so I changed that. I can run thru a successful manual regen but this produces the above code. Any advice? Thanks in advance! Quote Link to comment https://www.bigmacktrucks.com/topic/38041-2012-mp7-spn-5443-fmi-7-need-some-advice/ Share on other sites More sharing options...
wheeler73 Posted December 10, 2014 Share Posted December 10, 2014 What are your temps in the dpf and it sounds like you have a non catalyst dpf. I have seen the atomization modules go bad too. If it is a catalyst dpf the hydrocarbon dosing shut off modules go bad too. There are a lot of things it could be but those are the most common along with temp sensors. Quote Link to comment https://www.bigmacktrucks.com/topic/38041-2012-mp7-spn-5443-fmi-7-need-some-advice/#findComment-269847 Share on other sites More sharing options...
manolumber Posted December 13, 2014 Author Share Posted December 13, 2014 Thanks for the reply wheeler. It is a catalyzed system (SCR). A manual regen produces normal temps and the resulting soot reduction but trips the above code. Sounds like I may need the dpf dozer module? Thanks again for the reply Quote Link to comment https://www.bigmacktrucks.com/topic/38041-2012-mp7-spn-5443-fmi-7-need-some-advice/#findComment-270257 Share on other sites More sharing options...
wheeler73 Posted December 14, 2014 Share Posted December 14, 2014 Those are a common issue. How many hours are on the truck? Quote Link to comment https://www.bigmacktrucks.com/topic/38041-2012-mp7-spn-5443-fmi-7-need-some-advice/#findComment-270357 Share on other sites More sharing options...
manolumber Posted December 14, 2014 Author Share Posted December 14, 2014 Dont know how many hours but from memory I would guess about 200K miles. Is there ever an issue with the line from the dozer valve to the injector? Like an internal flap in the flex section of the line which blocks the line intermittently? Thanks again for sharing your experience! Quote Link to comment https://www.bigmacktrucks.com/topic/38041-2012-mp7-spn-5443-fmi-7-need-some-advice/#findComment-270375 Share on other sites More sharing options...
wheeler73 Posted December 15, 2014 Share Posted December 15, 2014 Not that I have seen. Stranger things have happened. Has the dpf been cleaned? They are supposed to be cleaned every 4500 hours. Quote Link to comment https://www.bigmacktrucks.com/topic/38041-2012-mp7-spn-5443-fmi-7-need-some-advice/#findComment-270482 Share on other sites More sharing options...
monstermatt Posted April 16, 2019 Share Posted April 16, 2019 Hello I have the same code sa 0 spn 5443 fm7 and have checked the hydrcarbon doser and its clean and clear! The soot level gauge says soot level s low. So would i still need to clean the dpf filters? ot is this just a hydro carbon doser module that is bad? and a notT to all the drivers out there. THERE IS TWO DIFFERENT DOSERS A DPF DOSER FOR DEF FLUID AND A HYDROCARBON OR DIESEL FUEL DOSER OR 7 TH INJECTOR IF YOU WILL.EACH RUN BY THEIR OWN MODULES.. Quote Link to comment https://www.bigmacktrucks.com/topic/38041-2012-mp7-spn-5443-fmi-7-need-some-advice/#findComment-420712 Share on other sites More sharing options...
Toyaa Posted October 8, 2021 Share Posted October 8, 2021 You need to clean filter in DPF , Definition : Fault In The DPF System - The Filter Is Plugged And Needs To Be Cleaned Out ( https://spnfmi.com/spn-5443-fmi-7 ) Quote Link to comment https://www.bigmacktrucks.com/topic/38041-2012-mp7-spn-5443-fmi-7-need-some-advice/#findComment-480982 Share on other sites More sharing options...
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