isx cm2250 enigne brake

[hct5]

we have checked almost all of this, this is the engine that was rebuilt by another shop. they had messed up installing one of the piston sleeves and it was leaking coolant into the oil. the head and injectors where tested when it was rebuilt maybe 1000 miles ago. not leaking turbo or doser, the decomp tube looks good. i just changed the temp sensor and try to do a DESA test and it stop saying the DOC outlet temp exceeded 1112 def. the dpf and doc are fairly new OEM. wondering if i should pull the doc and see what it looks like.