DPF / Regen's

            The Diesel Aftertreatment system were designed and introduced with the best intentions as a solution of riding our ozone layer of these harmful diesel product gases (PM and Nox Emissions) by essentially injecting Diesel Exhaust Fluid that is catalyzed through a chemical process of induction thermal dynamics.


            This has been made possible by relatively recent advances in filtration technology and initiatives by federal and state agencies to make huge strides in removing harmful pollutants from Diesel Exhaust Filters. The heavy-duty diesel engine after treatment system has two main components; exhaust after treatment technology and the SCR System. The exhaust aftertreament systemis mainly comprised of the diesel oxidation catalyst (DOC) and diesel particulate filter (DPF) with the goal of reducing and mitigating PM. The SCR, Select Catalytic reduction, system main purpose is to reduce the NOx emissions.


 How do DPFs and SCRs and the over aftertreament system work?


The DOC changes the chemistry in the exhaust system via utilizing heat to burn the soot into and ash, and the DPF stores the ash until its time to clean and have it removed via manual or forced Regens. When Regens fail, the soot level is too high and the DOC filter and possible the SCR and DPF needs to be physically removed from truck and sent out to be baked and cleaned. If the filters still fail and not filtrating as designed then these filters need to be replaced and installed into the truck.


The SCR system, through a chemical reaction, by the introduction of the diesel exhaust fluid (DEF), changes the molecular chemistry and eliminates the NOx and the greenhouse gases, so that you have minimum water and nitrogen coming out of the tailpipe. Thus your not having carbon dioxide coming out that gives you the greenhouse gas.

Common Root Causes:


If the DPF system is not maintained and passive regens are skipped or not completed fully, then there is a strong possibility the truck can go into "D-RATE" mode, which typically shows a Red Regen light on the dashboard and/or a Stop Engine light on many trucks. This occurs when the DOC and DPF are compromised with excessive soot causing a restriction of airflow.  When this happens, the truck has no power/performance while hitting the accelerator pedal. CALL us, and our experienced certified technicians who can perform an on-site road call to perform a forced Regen which will allow increased airflow as a temporary repair. Once the truck arrives in our shop in West Hartford, we will perform a full evaluation utilizing our modern tools and equipment and advise you as to the repair(s) necessary to regain proper operations.

  1. Not properly managing/maintaining these systems

  2. Often issues with DPF can be caused by unresolved upstream engine issues

      such as air or oil/fluid leaks.

3. Excessive idling can also cause premature clogging of a DPF due to high exhaust 

      temps (>1000 degrees) are needed to burn off the soot - cleaning the filter by 

     burning off the accumulated soot - known as passive Regeneration (REGEN)


Preventative maintenance and measure such as replacing gaskets and clamps regularly, schedule DPF cleanings and using a smoke machine to check for air leaks can extend the life of the expensive DPF, SCR and DOC filters. Lastly, using engine heater to minimize cold starts can greatly help reduce the amount of soot generated.


Please don't hesitate to CALL US NOW ask our experienced IFS team any and all questions and to schedule a DPF /Aftertreatment system maintenance, diagnostics and repairs. We have the Dealer level software for ALL makes and models to expedite any and all DPF / Aftertreatment system issues.