Originally Posted by MR.M
surely your not using the cruise going down steep grades or in snow , or even heavy rain ?
Each truck manufacturer has different strategies for controlling the VGT and the exhaust functions on their trucks.
Now this applies to the Ram diesel trucks with the latest generation of VGT software and how the trucks operate. I was in formed by the Ram engineers at the last TDR rally in Columbus IN. at the Cummins plant. The VGT software has a two stage exhaust brake the reason is too allow the truck to descend a grade with the cruise control on, the exhaust brake on and in T/H mode. This will maintain the set speed as you descend the said grade. This was tested when Ram was testing for the SAE J2807 Towing Requirments.
Times have changed and the computer controlled components on the newer trucks is truly amazing. Once upon the time the rules in the early days of vehicle controls is not the same as now.