Cummins isx 15 CM2250 silent derate

[JimT]

(03-09-2020 )krowbar91 Wrote:  I have a 2013 CM2250 Cummins in a Peterbilt 579 750,000 that has power loss. Engine was inframed 25,000 miles ago and deleted as well. Truck tripped a check engine light on and then derated. FMI codes 2346 and 2451 last week, 3/3/20.
Replaced with IMAP and turbo inlet temperature sensors. Check engine light has been cleared but truck is still derated with code 2346 staying inactive. FYI truck was fully serviced and a exhaust leak was repaired on DPF then the next day is when this issue happened. The VGT test was completed and passed as well. Intake and fuel system has been checked. Truck does well shifting through low side of transmission but has hardly any boost on the high gears. Any advised? Thanks

Not sure where or who did your demandate, but I'd venture to guess that is where the problem lies. Maybe they didn't properly hollow out ALL the cans (DOC, DPF and SCR). Or, maybe it's something bad in the programming itself. I'd lean toward the cans being clogged up since this started right after you fixed an exhaust leak. My guess is there is a good restriction in the exhaust that went unnoticed until the leak was fixed. Now the turbo is working overtime to try and overcome the backpressure.

But that is just a guess based on the little info you posted. If it wasn't demandated by someone mentioned on here then it's highly likely that it wasn't done correctly. If the cans are not 100% empty or if the SCR was left intact then it will reflect heat back toward the turbo and eventually the passages will clog up with soot, oil, or whatever is coming out of the engine.