This diagnostic function monitors the systems ability to maintain and regulate the DPF temperatures within acceptable limits based on current conditions like normal operation or during regenerations.

Conditions for diagnostic trouble code (DTC):
1) Automatic Regeneration, Only
2) During regeneration the temperature after the catalyst is too high for the existing conditions, above 800??C, (1472??F)

Observable symptoms
1) Automatic regeneration not possible
2) Regeneration aborted

Probable cause
1) Aftertreatment exhaust gas temperature (EGT) sensors installed in the incorrect location on the aftertreatment diesel particulate filter (DPF)
2) Aftertreatment Hydrocarbon Doser, over-fueling
3) Excessive smoke from the engine (High soot level)
4) Oil contamination, Excessive wear or damage to cylinder liners, piston, piston rings or turbocharger internal seals