Over the last 10 years or so, EPA regulations for diesel engines have focused primarily on two emissions components—oxides of nitrogen (NOx) and particulate matter (PM). We in California seem to be a little ahead of the EPA reg. schedule. The first year the DMAX was produced (2001), all 50 states had the same engine. No CAT/EGR. To further reduce the level of NOx, in 2002 the CA DMAX diesel engines were equipped with cooled exhaust gas recirculation (EGR) systems and a CAT. The EGR system along with retarded timing of the injection system lowered the combustion chamber temperature and resulting NOx level but produced more soot (or particulate matter). To meet the EPA/CARB regulations for particulate matter, a CAT was added to the exhaust system to control the soot level. The CAT on our trucks is solely for reducing the particulate matter (soot) to much finer size particles. The CAT is passive, no power or control go to it. The CAT is very simple. It only interacts with the exhaust flow. The above is MY understanding of the situation.
How any dealer can VOID your vehicle warranty because the CAT is missing is beyond me. Because it interacts only with the exhaust gases(and in a very simple way), it has no impact on the engine or the other parts of the vehicle. What Mackin says above in his first sentence is true, it is illegal to modify any emission system (Fed law). That is a different issue than the warranty.
Zoom ahead a few years to the 2007 timeframe. At this point, EPA mandated emission requirements for ALL on-road diesel vehicles increases substantially. At this point, the CAT's on a diesel truck will be more like those on cars. Made of more exotic metals and possibly multi-stage. There is a lot of research underway right now trying to determine how to meet the emission standards.
So Shaydog24, living in California, you know what is going to happen (right?). The state for sure will begin to inspect diesel equipped vehicles. I am rea
