Trailer towing is a excellent way to get the EGt's up. But pyrometer is a excellent way to see if you EGT's are just too cold.
The older Dodge didn't have any need for hot EGT's because there is technically no smog equipment. So now with the O2 sensors, DPF, and EGR valve you got to keep the temps up to control soot deposits.
OPERATION
The oxidation catalyst raises the exhaust gas temperatures to regenerate the DPF, which is passive regeneration. If the passive regeneration cannot keep up with the build up of soot in the DPF, the ECM will actively regenerate the DPF to burn off the soot. Residue remains inside the DPF in the form of non burnable ash. Ash comes from the oils and other materials that are trapped in the oils and are present in the soot. The catalyst contains a large number of parallel channels, which run in the axial direction and are separated by thin porous walls. The channels are alternatively open at one end, but plugged at the other. The exhaust gases flow through the walls and escape through the pores in the wall material. Particulates, however, are too large to escape and are trapped in the monolith walls. The ECM starts the regeneration of the DPF if the soot load exceeds a performance map value. The ECM determines the load condition of the DPF based upon the exhaust gas pressure upstream and downstream of the DPC/DPF. A pressure differential sensor provides the pressure input to the ECM. During the regeneration process, the ECM raises the temperature in the DOC/DPF to burn off the soot accumulated. Under normal operation, the engine does not produce enough heat to oxidize the soot inside the DOC/DPF. This process requires temperatures above 550°C (1,022°F). After regeneration, the ECM reads the actual pressure difference at the DOC/DPF and compares it with a reference value. From this comparison, the ECM determines the ash quantity inside the DOC/DPF.
