The National Highway Traffic Safety Administration is working with Stellantis to investigate potential high-pressure fuel pump failures in its 2018-2020 Ram trucks with the 6.7-liter Cummins diesel engine. According to an announcement by NHTSA Oct. 14, there have been 22 reports of pumps failing.
A diesel engine lives or dies, literally, by its high-pressure fuel pump, thanks to the massive pressures required to atomize diesel fuel sufficiently for efficient combustion. A failing or failed pump can cause stalling or a no-start condition. The NHTSA document states that so far all failures have happened at speeds over 25 mph.
This investigation hasn't yet been turned into a recall, nor is it clear how many vehicles would be affected if it gets elevated that far -- NHTSA estimates up to 604,651 -- but only time will tell for sure.