I followed the recommendation of a couple of drivers and a Cummins tech (which will remain nameless to protect him). It involved letting the engine sit overnight to cool completely. Then, turn key on without starting. Let sit like this for at least 10-15 seconds to ensure EGR valve in closed position. Then unplug the lower EGR plug wire. That's it. No need to repeat process at each start. Only if EGR plugged reconnected.
It did throw a fault code, but no CEL or "limp" or derate mode in the ECM. From others I have discussed this with, certain truck makes will react differently, i.e. throw a CEL or multiple faults. I am concluding that this is relative to the engine model year and how the engine communicates with the truck's vehicle information center. I have a '06 International 9400i with the ISX. Hardly any engine information is passed to the limited display info. From experience, I have seen Volvo trucks display everything up to almost including the last time the driver wiped his rear. Therefore, depending on the engine/vehicle/year combination, the results may be different.
That being said, there are a number of us that have tried this procedure with good results. It would appear that this not a viable option for those with the DPF systems. It seems limited to those with pre-07 EGR equipped ISX engines. The pre-07 engines seem to not have as many sensors giving detailed EGR data to the ECM like positioning and flow rates.
