Failure mode - Cummins 6.7L ISB Diesel (Ram HD, 2019+ generation)

DPF/SCR aftertreatment problems (2019+ 6.7)

Reliability tier: verified - verify before ordering, see /disclosure/

Symptoms

'exhaust filter full' / regen messages; DEF quality warnings; speed-limiting derates
failed regens on short trips; NOx sensor faults

Compare with the other causes of the same sign on this engine: loss of power, limp mode or derate (4 causes) · def, dpf and regeneration warnings (2 causes)

Root cause

The 2019+ trucks run the full 2013+ aftertreatment family (EGR + DPF + SCR/DEF). Duty-cycle regen problems, DEF quality/freezing and NOx/DPF sensor faults drive the same inducement behaviour as the 2013-2018 trucks.

Diagnosis

read soot-load/DEF DTCs first; verify regen completes at highway load
rule out VGT/EGR faults that block regen conditions

Fixes

service the aftertreatment path: sensors, DEF quality, DPF cleaning/replacement as indicated ()

Prevalence

common

Parts for this repair run about $90-$1,200: see them next to the other repairs on this engine in repair costs.